Central Heating help
Peter Parker
water heater which we want to replace with a wet system as the ducts
don't go all over the house and the water flow is rubbish.
Severn Trent have kindly put a 25mm section in from the main to the
stopcock which I need to extend into the house. Is there anything
particular i need to be aware of when doing this? How easy is 25mm
MDPE to work with?
Also once done, what boiler should I go for. I've done all the heat
loss calculations(we have a dormer bungalow) and it comes out at about
11Kw. We mostly use showers but need the bath for young children. As
we've got a dry loft, which decent flow rate combi's are reliable or
if I go for stored water what is the major benefit of an unvented
cylinder over a heat bank(a heat bank with no overflow or pressure
vent would be a lot easier to fit)?
I would prefer a condensing, modulating boiler but want reliability
and there are so many contradictory opinions on which ones are good
it's doing my head in!
Thanks.
Christian McArdle
>loss calculations(we have a dormer bungalow) and it comes out at about
>11Kw. We mostly use showers but need the bath for young children.
How many bathrooms?
The advantage of a stored mains pressure system over a combi is that it
fills the bath in no time, and will probably run several showers
simultaneously, if you have them. Your 25mm MDPE will almost certainly
provide lashings of water, although you should still test it, in case the
water main is no good.
However, if the bath is only used for young children, who generally have a
very low water level, a combi will probably surfice.
Christian.
Andy Hall
wrote:
I won't say much about the supply, other than to suggest that you
check the flow rate of the supply (not the static pressure) before you
commit to any form of mains pressure hot water system.
You could check that at the kitchen cold tap now by timing measured
quantities of water. If you can get 20 litres/min or more then you
are in good shape and improving the main from the stop cock and then
using 22mm pipe internally at least as far as the water heating device
will be good.
I did a boiler replacement last year and short listed down to MAN
Micromat, Keston Celsius 25 and Vaillant. I was looking for a
condensing, modulating boiler and not a combi. I already had stored
water and the mains flow is poor so I did't want to go the mains route
because upgrading would be expensive in my case. Several boilers
that might have been suitable were rejected on physical size.
In deciding whether a combi is good enough you need to look at your
present and projected needs. The main point would be whether you want
to fill a bath and run a shower at the same time or can live with the
restriction of one at a time. There are combis around that will do
20 litres/min, but this is marginal if you want to fill a bath and
shower simultaneously - once the kids are larger you may well.
Bear in mind also that the ratings for combis are for a 30 or 35
degree temperature rise from cold, so in the winter the *total*
throughput will be used to run a shower at 40 degrees.
With a pressurised HW cylinder, you are storing the water at 60
degrees and always mixing with some cold, so your rate of availability
will be more than with a combi. If the water supply will do it,
perhaps over 30 litres/min even in winter. This type of cylinder
and its safety equipment have to be fitted by a BBA approved
installer, however.
With a heat bank, the mass of water is not pressurised but is open
vented to a small tank in the top of the device or the loft. This
mass of water is heated through the boiler using a circulating pump
and then separate feeds are taken from it for the hot water and CH.
The DHW is heated using a stainless steel plate heat exchanger.
These can easily transfer heat at 100 or 200kW, so the limitation is
likely to be that of how much the mains water can supply.
Because they are not pressurised for the large volume of water, you
can DIY the installation.
Typically, a heat bank is run at 80 degrees, so more energy is stored
than with a pressurised HW cylinder. In effect, therefore, a shower
will run for longer. There is a caveat, however - later.
In practice, it becomes slightly more complex because the boiler will
be replacing energy in the cylinder almost as soon as you turn on the
hot tap. However, if you are using water at a high rate, then on a
net basis you will still be taking energy out faster than it goes in,
so ultimately the temperature at the tap will drop, or you will have
to reduce the flow rate. This principle applies to both a sealed
cylinder and a heat bank. The point is to design in enough storage
that you don't reach that stage.
Regarding condensing boilers, I don't know whether you have noticed
that efficiency improves with reducing return water temperature. This
is an important point. People get confused about the action and
effect that condensing has and it's important to realise that it is
not a Holy Grail where all the benefit happens at one point.
Condensing happens at the dew point (around 54 degrees on the return).
Heat is released from the flue gases which would otherwise go out of
the flue because the change of state from gas (steam) to liquid (water
or water vapour). The boiler is able to recover this heat usefully.
People think, and some manufacturers don't disavow them that all of
the useful gain in efficiency happens at the dew point and that there
is a step change in efficiency. This isn't the case. In fact, the
efficiency increases with reducing temperature from the top of the
operating temperature range (80) to the bottom (30). At the dew
point, the *rate* of increase improves with reducing temperature.
In other words, the lower you can get the temperature, the better -
it's not a case of stopping at the dew point. It's also fairly well
known that there is an inefficiency associated with turning the
burners on and off, which is why the idea of modulating has become
prevalent.
I did look at heat banks fairly thoroughly, before not being able to
use a mains system anyway. One of the problems I saw was that in
getting the temperature up to 82 degrees to maximise energy storage,
the boiler return temperature is going to be in the 62-65 degree
range. A condensing boiler will be on the lower efficiency curve at
that temperature. One therefore sees suggestions in manufacturers
information of running the cylinder cooler or using a mixing valve.
This implies running the store at, say, 74 degrees to reach the 54
degree return temperature which is the maximum for condense mode.
The suggestion given is that this is good enough because condensing
mode has been achieved when that really isn't the case. Logically,
reducing the temperature further is needed to maximise efficiency; and
at that point the advantage vs straight HW storage goes away.
So I was unconvinced about the case for partnering a condensing boiler
with a heatbank. A conventional boiler would be different because it
is designed to operate at the higher temperature.
One point worth mentioning is that there is nothing to stop you using
a combi *and* storage for different parts of the house.
I decided that I wanted to design for the best operating conditions
where I could also get a lot of hot water when required. Hence my
choice was a fairly large HW cylinder (210 litres) with fast recovery
heat exchanger, and then to design the heating to operate most
efficiently with the boiler.
If you have looked at the books or at radiator sizing software, in
most cases they help you to size everything for a conventional boiler
of 82 degree flow, 70 degree return, with -1 or -3 outside.
A condensing boiler will do these temperatures but not at it's most
efficient. Of course, when the weather is warmer, not so much heat
is required, so the boiler modulates down as does the temperature of
the return, so the boiler becomes more efficient. Hence, the
condensing boiler does OK in the replacement market because at least
in spring and autumn it will run in the more efficient range.
I had the opportunity of some redesign, and you do as well. A better
solution is to choose radiators on the basis of 70 degrees flow and 50
degrees return for the -1/-3 outside temperature. Then you will
always be operating on the condensing part of the curve. Basically
this involves uprating the radiators by about 40% on the values given
by a radiator sizing program or chart.
The remaining aspect is to have the boiler in modulation rather than
on/off as much as possible, so I looked for products that will do
this. The Keston will modulate down to 7kW and the MAN Micromat
down to 3kW. Some products will only modulate down to 10kW.
Considering your load (presumably calculated at 11kW for winter
conditions), the implication is that you won't be in modulating mode
for much of the time.
I eventually purchased the MAN Micromat 23kW model which meets all of
the requirements and also has outside temperature compensation and
linear modulation of the pump to match the load. This further
improves responsiveness. There is a combi version as well, but I
went for the non-combi.
Other factors I considered were build quality, programmability and
servicability. The German products have the edge here in my view.
The MAN products (same company that makes trucks and diesel engines)
are represented in the UK through MHS Boilers and Eco Hometec.
Both are distributors and supply direct.
Needless to say, they are not the least expensive make, but I was able
to obtain a 5 year parts and labour warranty.
Energy saving has been as predicted as well.
.andy
To email, substitute .nospam with .gl
abuse-imm@easy.com IMM
news:67ihav0t30b4enbp2...@4ax.com...
> We've inherited a Johnson & Starley warm air unit(J40) and Mersey
> water heater which we want to replace with a wet system as the ducts
> don't go all over the house and the water flow is rubbish.
Keep the warm-air unit. Install a combi with a good flowrate (e.g., the
Wickes Combi 102 gives 13 litres/min) in place of the main Mersey, and where
you don't have heat install rads run off the combi. Sorted. No cylinders,
tanks, etc. Simple to fit and pipe up and gives high pressure showers too.
Who wants rads on walls when you don't have to have them, as is the case
with you. This is the most cost effective way to get what you want.
> We mostly use showers but need the bath
> for young children.
Young children only have 1/2 filled baths anyhow, so no problem in filling
that with a combi.
> As we've got a dry loft,
> which decent flow rate combi's are reliable or
> if I go for stored water what is the major
> benefit of an unvented cylinder over a heat
> bank(a heat bank with no overflow or pressure
> vent would be a lot easier to fit)?
If you are doing it yourself then go heat bank as you need a BBA approved
fitter for the unvented cylinder.
> I would prefer a condensing, modulating
> boiler but want reliability and there are so
> many contradictory opinions on which ones are good
> it's doing my head in!
Anyone who says condensers are unreliable is talking balls.
I would keep the warm-air and go combi for DHW and heating the rest. This
gives heat backup too. If one drops out you at least have heat in the
house.
abuse-imm@easy.com IMM
"IMM" <abuse: abus...@easy.com> wrote in message
news:b8bk8s$t29$1...@newsg1.svr.pol.co.uk...
I forgot to mention that going warm air and combi will give two heat zones,
so gas savings there. The rads (assume heating bedrooms) can be off all day
and only come on at bedtimes.
Dave Plowman
IMM <abuse: abus...@easy.com> wrote:
> > We've inherited a Johnson & Starley warm air unit(J40) and Mersey
> > water heater which we want to replace with a wet system as the ducts
> > don't go all over the house and the water flow is rubbish.
> Keep the warm-air unit.
Perhaps you like part central heating. The OP obviously doesn't.
--
*Change is inevitable, except from a vending machine.
Dave Plowman dave....@argonet.co.uk London SW 12
RIP Acorn
abuse-imm@easy.com IMM
"Andy Hall" <an...@hall.nospam> wrote in message
news:cb8iav469k5rv0otv...@4ax.com...
> With a heat bank, the mass of water
> is not pressurised but is open
> vented to a small tank in the top
> of the device or the loft.
Some heat banks are pressurised.
> Typically, a heat bank is run at 80
> degrees, so more energy is stored
> than with a pressurised HW cylinder.
Untypical! most now store the hot water at 75-76C. FRom the range cylinder
web site:
How It Works - Hot Water
Flowmax differs from conventional cylinders in that the water stored is not
the same water that is delivered to the taps. It should be thought of as a
store of heat. This primary store is typically maintained at 75 degrees C. A
50mm layer of CFC free insulation keeps heat loss to a minimum.
The heat heart of the Flowmax is the plate heat exchanger. Mains pressure
cold water is heated instantaneously as it passes through this heat
exchanger. A flow switch detects the hot water demand and switches on the
store pump to assist heat exchange. Hot water can leave the plate heat
exchanger at over 60 degrees C. A thermostatic mixing valve ensures water is
delivered at a safe temperature.
The Store is vented via a feed and expansion tank. Only the inside of the
plate heat exchanger is at mains pressure. Flowmax electric units are heated
by two immersion heaters and provide hot water only. Boiler models are
heated by gas or oil and in addition to hot water can also provide heat
directly to space heating (typically radiators).
> In practice, it becomes slightly more complex
> because the boiler will be replacing energy in
> the cylinder almost as soon as you turn on the
> hot tap.
Uh! Most do not. Most wait untill the water in the store is well depleted
to give a long efficient burn on re-heat. Some use two cylinder stats to
achieve this, one top and one bottom. Well worth doing.
> However, if you are using water at
> a high rate, then on a net basis you
> will still be taking energy out faster
> than it goes in, so ultimately the
> temperature at the tap will drop,
> or you will have to reduce the flow rate.
You size the heat bank to overcome this.
> Regarding condensing boilers,
>
> In other words, the lower you can
> get the temperature, the better -
> it's not a case of stopping at the dew point.
> It's also fairly well known that there is
> an inefficiency associated with turning the
> burners on and off, which is why the idea
> of modulating has become prevalent.
Or using a heat bank that heats all the water in one go.
> I did look at heat banks fairly thoroughly,
> before not being able to use a mains
> system anyway. One of the problems
> I saw was that in getting the temperature
> up to 82 degrees to maximise energy storage,
Most use 75C now. See above.
> So I was unconvinced about the
> case for partnering a condensing boiler
> with a heatbank.
That is because you didn't know too much about them. You should have asked
me. :)
> A conventional boiler would be different because it
> is designed to operate at the higher temperature.
A good conventional boiler mated to a heat bank with two cylinder stats and
a blending valve on the flow and return will produce very high efficiencies.
In most cases above what some condensing boilers can achieve on conventional
systems. The "seasonal" efficiencies of SEDBUK give 8.4% for the best
non-condensing boiler. When mated to a heat bank, a boiler is operating at
maxium efficiency and to a set condition at all times. A regular boiler can
attain 90% efficiency at peak. Mated to a hgeat bank it is at peak 90%+ of
the time.
> The remaining aspect is to have the
> boiler in modulation rather than
> on/off as much as possible,
No, with a heat bank you don't. You want the burner full on. The good
thing about a heat banks is that you can use a simpler cheaper boiler. So,
when you price up a heat bank it is best to incorporate the heat bank and
boiler and compare it to a boiler/unvented cylinder or whatever in other
systems.
Andy Hall
wrote:
>
>> Typically, a heat bank is run at 80
>> degrees, so more energy is stored
>> than with a pressurised HW cylinder.
>
>Untypical! most now store the hot water at 75-76C.
Which makes it less interesting since the energy stored is less.
>
>> In practice, it becomes slightly more complex
>> because the boiler will be replacing energy in
>> the cylinder almost as soon as you turn on the
>> hot tap.
>
>Uh! Most do not. Most wait untill the water in the store is well depleted
>to give a long efficient burn on re-heat. Some use two cylinder stats to
>achieve this, one top and one bottom. Well worth doing.
This means that the system capacity will be reduced since you are not
starting to put energy back until it's almost used. In the case of HW
this will mean that the period during which hot water can be diluted
with cold will be shorter than if the boiler started almost
immediately.
>
>> However, if you are using water at
>> a high rate, then on a net basis you
>> will still be taking energy out faster
>> than it goes in, so ultimately the
>> temperature at the tap will drop,
>> or you will have to reduce the flow rate.
>
>You size the heat bank to overcome this.
Which along with running at 75 degrees somewhat negates the point.
>
>> Regarding condensing boilers,
>>
>> In other words, the lower you can
>> get the temperature, the better -
>> it's not a case of stopping at the dew point.
>> It's also fairly well known that there is
>> an inefficiency associated with turning the
>> burners on and off, which is why the idea
>> of modulating has become prevalent.
>
>Or using a heat bank that heats all the water in one go.
>
>> I did look at heat banks fairly thoroughly,
>> before not being able to use a mains
>> system anyway. One of the problems
>> I saw was that in getting the temperature
>> up to 82 degrees to maximise energy storage,
>
>Most use 75C now. See above.
This is marketing to try and convince people that this
means that a condensing boiler will be operating at good efficiency
which is misleading.
>
>> So I was unconvinced about the
>> case for partnering a condensing boiler
>> with a heatbank.
>
>That is because you didn't know too much about them. You should have asked
>me. :)
My own research was based on sound principles of physics, which have
always served me well. I didn't think that you could improve on
them.......
>
>> A conventional boiler would be different because it
>> is designed to operate at the higher temperature.
>
>A good conventional boiler mated to a heat bank with two cylinder stats and
>a blending valve on the flow and return will produce very high efficiencies.
>In most cases above what some condensing boilers can achieve on conventional
>systems. The "seasonal" efficiencies of SEDBUK give 8.4% for the best
>non-condensing boiler. When mated to a heat bank, a boiler is operating at
>maxium efficiency and to a set condition at all times. A regular boiler can
>attain 90% efficiency at peak. Mated to a hgeat bank it is at peak 90%+ of
>the time.
To have really meaningful results, one has to look at system
efficiencies which take into account all the components including the
thermal behaviour of the house and the control systems.
>
>> The remaining aspect is to have the
>> boiler in modulation rather than
>> on/off as much as possible,
>
>No, with a heat bank you don't.
> You want the burner full on. The good
>thing about a heat banks is that you can use a simpler cheaper boiler. So,
>when you price up a heat bank it is best to incorporate the heat bank and
>boiler and compare it to a boiler/unvented cylinder or whatever in other
>systems.
I was talking about condensing boilers, since this was the question
asked.
abuse-imm@easy.com IMM
> >> Typically, a heat bank is run at 80
> >> degrees, so more energy is stored
> >> than with a pressurised HW cylinder.
> >
> >Untypical! most now store the hot water at 75-76C.
>
> Which makes it less interesting since
> the energy stored is less.
Duh! Then you have a larger store.
> >> In practice, it becomes slightly more complex
> >> because the boiler will be replacing energy in
> >> the cylinder almost as soon as you turn on the
> >> hot tap.
> >
> >Uh! Most do not. Most wait untill the water
> >in the store is well depleted to give a long
> >efficient burn on re-heat. Some use two
> >cylinder stats to achieve this, one top and
> >one bottom. Well worth doing.
>
> This means that the system capacity will
> be reduced
No it will not.
> since you are not
> starting to put energy back until it's
> almost used. In the case of HW
> this will mean that the period during
> which hot water can be diluted
> with cold will be shorter than if the
> boiler started almost immediately.
You set it up to suit, so that you don't run out of DHW in nornal usage.
You can also have the energy of the store and the energy of the boiler
"combined" to give very high flow rates and/or a smaller store. One that
will fit under a worktop and still do the average house.
> >> However, if you are using water at
> >> a high rate, then on a net basis you
> >> will still be taking energy out faster
> >> than it goes in, so ultimately the
> >> temperature at the tap will drop,
> >> or you will have to reduce the flow rate.
> >
> >You size the heat bank to overcome this.
>
> Which along with running at 75 degrees
> somewhat negates the point.
You obviously don't understand this.
> >> Regarding condensing boilers,
> >>
> >> In other words, the lower you can
> >> get the temperature, the better -
> >> it's not a case of stopping at the dew point.
> >> It's also fairly well known that there is
> >> an inefficiency associated with turning the
> >> burners on and off, which is why the idea
> >> of modulating has become prevalent.
> >
> >Or using a heat bank that heats all the
> >water in one go.
> >> I did look at heat banks fairly thoroughly,
> >> before not being able to use a mains
> >> system anyway. One of the problems
> >> I saw was that in getting the temperature
> >> up to 82 degrees to maximise energy storage,
> >
> >Most use 75C now. See above.
>
> This is marketing to try and convince
> people that this means that a condensing
> boiler will be operating at good efficiency
> which is misleading.
It is not a marketing ploy. They adjusted heat banks to accommodate
condensing boilers. Simple!
> >> So I was unconvinced about the
> >> case for partnering a condensing boiler
> >> with a heatbank.
> >
> >That is because you didn't know too
> >much about them. You should have asked
> >me. :)
>
> My own research was based on sound
> principles of physics, which have
> always served me well. I didn't think that
> you could improve on them.......
You could improve by understanding heat banks and what they can give you.
> >> The remaining aspect is to have the
> >> boiler in modulation rather than
> >> on/off as much as possible,
> >
> >No, with a heat bank you don't.
> >You want the burner full on. The good
> >thing about a heat banks is that you can
> >use a simpler cheaper boiler. So,
> >when you price up a heat bank it is best
> >to incorporate the heat bank and
> >boiler and compare it to a boiler/unvented
> >cylinder or whatever in other systems.
>
> I was talking about condensing boilers,
..and heat banks. And I am stating the ways of getting max efficiency from
them.
Andy Hall
wrote:
>"Andy Hall" <an...@hall.nospam> wrote in message
>news:615javka23rh560cp...@4ax.com...
>
>> >> Typically, a heat bank is run at 80
>> >> degrees, so more energy is stored
>> >> than with a pressurised HW cylinder.
>> >
>> >Untypical! most now store the hot water at 75-76C.
>>
>> Which makes it less interesting since
>> the energy stored is less.
>
>Duh! Then you have a larger store.
At 75 degrees you are only storing 25% more energy than if you
used the same sized HW cylinder whatever the size. What's the point?
You might as well have a condensing boiler and a fast recovery
cylinder and done with it.....
>> >
>> >Uh! Most do not. Most wait untill the water
>> >in the store is well depleted to give a long
>> >efficient burn on re-heat. Some use two
>> >cylinder stats to achieve this, one top and
>> >one bottom. Well worth doing.
>>
>> This means that the system capacity will
>> be reduced
>
>No it will not.
>
Of course it will but let me be clear about what I mean by capacity in
this context to avoid a wild goose chase. I'm talking about the
amount of DHW at the temperature at which it will be used - 40-50
degrees and at the required rate. If you have a HW cylinder or a
heat bank and you start taking energy from it but don't replace it
until what is stored is almost depleted, then the volume of useful hot
water will be less than if the boiler is turned on earlier during the
usage of water. Eventually, whatever you have, the stored energy
will have run out and the heat being pushed into the water will equal
what the boiler can provide. At this stage you are left in effect
with an instantaneous heater - not very useful.
>> since you are not
>> starting to put energy back until it's
>> almost used. In the case of HW
>> this will mean that the period during
>> which hot water can be diluted
>> with cold will be shorter than if the
>> boiler started almost immediately.
>
>You set it up to suit, so that you don't run out of DHW in nornal usage.
>You can also have the energy of the store and the energy of the boiler
>"combined" to give very high flow rates and/or a smaller store.
The "combining" effect only happens if the boiler is running while you
are pulling energy from the store. If you wait to start the boiler
until the store or cylinder is nearly depleted then there is very
little combining effect.
>One that
>will fit under a worktop and still do the average house.
That's complete nonsense. If you take a 600mm^2 footprint under a
worktop of 800mm height you can fit approx. an 80 litre store - and
that's without allowing for the mass of pumps, valves and assorted
bits and pieces required for a heatbank.
If this is run at 75 degrees, it will be equivalent to a standard HW
cylinder of 100 litres at 60 degrees. This is not enough for an
average house by 30-40%.
>
>> >> However, if you are using water at
>> >> a high rate, then on a net basis you
>> >> will still be taking energy out faster
>> >> than it goes in, so ultimately the
>> >> temperature at the tap will drop,
>> >> or you will have to reduce the flow rate.
>> >
>> >You size the heat bank to overcome this.
>>
>> Which along with running at 75 degrees
>> somewhat negates the point.
>
>You obviously don't understand this.
I obviously do - it's simple physics.
Fact 1: If you store water at 75 degrees you get only 25% more energy
out of it than at 60 degrees.
Fact 2: If you don't begin replacing energy immediately you start to
take it out, the supply capacity of the system is reduced compared
with if you did.
>>
>> This is marketing to try and convince
>> people that this means that a condensing
>> boiler will be operating at good efficiency
>> which is misleading.
>
>It is not a marketing ploy. They adjusted heat banks to accommodate
>condensing boilers. Simple!
Dropping the temperature of the store to 75 degrees so that the return
to the boiler can be at 55 degrees is purely so that the manufacturer
can claim that the boiler is in "condensing mode". This is a
complete con. The efficiency of the boiler doesn't suddenly jump
when you reduce the return temperature to 54 degrees and it is
condensing vs. 56 and it's not. If you follow this logic, you hould
be running the store at 50 degrees and a return of 30 to get more out
of the boiler.
>
>> >> So I was unconvinced about the
>> >> case for partnering a condensing boiler
>> >> with a heatbank.
>> >
>> >That is because you didn't know too
>> >much about them. You should have asked
>> >me. :)
>>
>> My own research was based on sound
>> principles of physics, which have
>> always served me well. I didn't think that
>> you could improve on them.......
>
>You could improve by understanding heat banks and what they can give you.
I know that you would like to have things defy physics, operate like
the Tardis and get more out than you put in, but sadly physics doesn't
support you in it in the present state of our knowledge.
>
>> >> The remaining aspect is to have the
>> >> boiler in modulation rather than
>> >> on/off as much as possible,
>> >
>> >No, with a heat bank you don't.
>> >You want the burner full on. The good
>> >thing about a heat banks is that you can
>> >use a simpler cheaper boiler. So,
>> >when you price up a heat bank it is best
>> >to incorporate the heat bank and
>> >boiler and compare it to a boiler/unvented
>> >cylinder or whatever in other systems.
>>
>> I was talking about condensing boilers,
>
>..and heat banks. And I am stating the ways of getting max efficiency from
>them.
>
But there's little or no value in it. You don't get the max
efficiency out of a condensing boiler by pairing it with a heat bank,
because it has to run hotter than if you simply let it run the
radiators directly - when it can drop down as low as 50/30.
If you use the heatbank only in connection with producing hot water,
it does nothing that you can't achieve much more simply by having a HW
cylinder 25% larger than the equivalent heatbank.
If you want to pair a conventional boiler with a peak efficiency of 80
degrees with a heatbank, that may be a different discussion.
Peter Parker
I didn't mean to spark the Andy/IMM debate again.
It's just that that hot air doesn't supply the bathroom downstairs or
another bathroom with sink & shower and 2 more rooms upstairs since it
was a converted loft.
I want rid of the hot air heater as it sits in the middle of the house
and the flue cuts straight through the room upstairs. I would have
liked to have sited a new boiler & cylinder in the same cupboard as it
has a gas supply, but as it's in the middle of the house I can't
plumb a condensate drain or flue it easily. Likewise I think I need a
pressure/temperature relief valve on an unvented cylinder discharging
outside which I can't do from there either?
I can't really have any feed/expansion tanks for an unvented system
upstairs which is why I mention heat banks which can incorporate one
or not need one.
I like the idea of a modulating condenser and think I can get away
with siting it in the kitchen but finding room for the cylinder is the
problem.
The existing mains pipe is only 15mm but the water man says it's 3 bar
and should be alright for flow with a bigger pipe.
Andy Hall
wrote:
>Sorry,
>I didn't mean to spark the Andy/IMM debate again.
Let's look at what options you have. Sometimes the logistics affect
the choices.
>It's just that that hot air doesn't supply the bathroom downstairs or
>another bathroom with sink & shower and 2 more rooms upstairs since it
>was a converted loft.
This also has some implications on running the CH circuit. If you
can't put a small header tank at about a metre above upstairs
radiators you would need to run the CH circuit sealed and pressurised.
>I want rid of the hot air heater as it sits in the middle of the house
>and the flue cuts straight through the room upstairs. I would have
>liked to have sited a new boiler & cylinder in the same cupboard as it
>has a gas supply, but as it's in the middle of the house I can't
>plumb a condensate drain or flue it easily.
Is there no toilet or bathroom on the ground floor in the centre of
the house? If so, you could run the condensate drain to there. It
doesn't have to go to the outside. For the flue, some boilers like
the Keston Celsius use 50mm muPVC (high temperature waste pipe) for
inlet and outlet. Others (like the MAN) can have adaptors to
accomodate this type of pipe. If that's really no good, then a
spot at the outside of the house will be needed, and you will need to
provide gas, condensate drain and pressure relief valve drain.
A combi large enough to give a decent flow rate is going to be harder
to find a home for than a small system boiler like the Keston.
> Likewise I think I need a
>pressure/temperature relief valve on an unvented cylinder discharging
>outside which I can't do from there either?
Yes you do and there are tight rules in the Building Regulations
section G on sizes and slopes for the discharge pipe.
>I can't really have any feed/expansion tanks for an unvented system
>upstairs which is why I mention heat banks which can incorporate one
>or not need one.
An unvented system wouldn't need feed/expansion tanks - the problem
you have is not wanting to have any overflows or pressure relief
discharges in your cupboard.
My point regarding heatbanks was not that they are a bad idea but that
with a condensing boiler they aren't going to perform more efficiently
than a normal cylinder. The main effect of using one is to store the
energy and release it quickly through the plate heat exchanger - to
much better effect than a combi in terms of HW flow rate. In your
situation it could be a useful solution to get around the
overflow/discharge issues.
As you say, there are models which incorporate an unpressurised
expansion vessel.
Coming back to the issue of the need to have the CH circuit sealed;
the implication with a heat bank is that you would need an indirect
one. These have a primary coil (akin to the coil on a sealed
cylinder). This coil, the CH circuit, the boiler and all the rest
of the primary would be sealed and pressurised. Some boilers
incorporate an expansion vessel, whereas with others you need a
separate one. Note that you could put the expansion vessel for the
primary circuit in your cupboard but have the pressure relief valve
and filling loop near the boiler if you like.
The mass of water in the heatbank would be heated to an appropriate
temperature - e.g. 75-80 degrees - the trade off being amount of
energy stored vs. efficiency. You could always vary it seasonally of
course. Since the water in the heatbank is only used within the
appliance itself, there are no issues of pressure head for the floor
above.
The cold water would be heated by a plate heat exchanger using water
pumped from the store.
>I like the idea of a modulating condenser and think I can get away
>with siting it in the kitchen
So do I, and I have saved the predicted amount of energy of 25-30%.
Having the primary indirect means that the boiler will modulate right
down when feeding the CH circuit when there is little demand. You
will get the real condensing boiler savings then. WHen switched to
the store to heat the water, the boiler will run at a much higher
level, which is not its most efficient, but generally performance for
HW is more important. There is nothing to stop you reducing the store
temperature further if you wish.
>but finding room for the cylinder is the
>problem.
The cupboard? As I mentioned before, I wouldn't go for the small
under worktop stores. I think you would be disappointed with the
capacity.
>The existing mains pipe is only 15mm but the water man says it's 3 bar
>and should be alright for flow with a bigger pipe.
It's really the flow rather than static pressure that matters. Did
you measure the flow rate as it is today.
?
abuse-imm@easy.com IMM
> On Sat, 26 Apr 2003 13:55:43 +0100, "IMM" <abuse: abus...@easy.com>
> wrote:
>
> >"Andy Hall" <an...@hall.nospam> wrote in message
> >news:615javka23rh560cp...@4ax.com...
> >
> >> >> Typically, a heat bank is run at 80
> >> >> degrees, so more energy is stored
> >> >> than with a pressurised HW cylinder.
> >> >
> >> >Untypical! most now store the hot water at 75-76C.
> >>
> >> Which makes it less interesting since
> >> the energy stored is less.
> >
> >Duh! Then you have a larger store.
>
> At 75 degrees you are only storing
> 25% more energy than if you
> used the same sized HW cylinder
> whatever the size. What's the point?
> You might as well have a condensing
> boiler and a fast recovery
> cylinder and done with it.....
You can then have a heat bank that "combines" the heat of the store "and"
the boiler and keep the store size down.
> >> >Uh! Most do not. Most wait untill the water
> >> >in the store is well depleted to give a long
> >> >efficient burn on re-heat. Some use two
> >> >cylinder stats to achieve this, one top and
> >> >one bottom. Well worth doing.
> >>
> >> This means that the system capacity will
> >> be reduced
> >
> >No it will not.
>
> Of course it will but let me be clear
> about what I mean by capacity in
> this context to avoid a wild goose chase.
> I'm talking about the amount of DHW at
> the temperature at which it will be used - 40-50
> degrees and at the required rate. If you
> have a HW cylinder or a heat bank and you
> start taking energy from it but don't replace it
> until what is stored is almost depleted,
> then the volume of useful hot water will be
> less than if the boiler is turned on earlier during the
> usage of water.
Then you set the controls to bring in the boiler earlier. Simple. I did say
that, read below.
> >> since you are not
> >> starting to put energy back until it's
> >> almost used. In the case of HW
> >> this will mean that the period during
> >> which hot water can be diluted
> >> with cold will be shorter than if the
> >> boiler started almost immediately.
> >
> >You set it up to suit, so that you
> >don't run out of DHW in nornal usage.
> >You can also have the energy of the
> >store and the energy of the boiler
> >"combined" to give very high flow rates
> >and/or a smaller store.
>
> The "combining" effect only happens
> if the boiler is running while you
> are pulling energy from the store.
Obviously!
> If you wait to start the boiler
> until the store or cylinder is nearly
> depleted then there is very
> little combining effect.
You can:
1. Have two cyl stats that ensure the store is depleted "enough" to bring in
the boiler for an efficient long burn.
2. Have the boiler and store "combine" to give high outputs.
3. A mixture of the two above in that the store will be depleted somewhat
and then the boiler cuts in.
You have the choice.
> >One that
> >will fit under a worktop and still
> >do the average house.
>
> That's complete nonsense.
Please!! There is only so much I will take from a rank amateur. If I say
so, it is so. If you don't understand then ask, if you still don't then
just accept.
> Fact 2: If you don't begin replacing energy
> immediately you start to
> take it out, the supply capacity of the
> system is reduced compared with if you did.
You can do, if you set the controls to do so. The store acts a "store" and
a "buffer"
> >> This is marketing to try and convince
> >> people that this means that a condensing
> >> boiler will be operating at good efficiency
> >> which is misleading.
> >
> >It is not a marketing ploy. They adjusted
> >heat banks to accommodate
> >condensing boilers. Simple!
>
> Dropping the temperature of the store
> to 75 degrees so that the return
> to the boiler can be at 55 degrees is
> purely so that the manufacturer
> can claim that the boiler is in "condensing
> mode".
Some boilers can drop below 20c delta T.
> This is a complete con.
It is not. It is engineering the heat bank to accommodate a condensing
boiler and create more efficiencies.
> >> My own research was based on sound
> >> principles of physics, which have
> >> always served me well. I didn't think that
> >> you could improve on them.......
> >
> >You could improve by understanding heat
> >banks and what they can give you.
>
> I know that you would like to have things
> defy physics,
You should have understood heat banks, how they work and how you can
accomodate one to suit your needs, not look at O level phyics books. You
failed.
> >> >> The remaining aspect is to have the
> >> >> boiler in modulation rather than
> >> >> on/off as much as possible,
> >> >
> >> >No, with a heat bank you don't.
> >> >You want the burner full on. The good
> >> >thing about a heat banks is that you can
> >> >use a simpler cheaper boiler. So,
> >> >when you price up a heat bank it is best
> >> >to incorporate the heat bank and
> >> >boiler and compare it to a boiler/unvented
> >> >cylinder or whatever in other systems.
> >>
> >> I was talking about condensing boilers,
> >
> >..and heat banks. And I am stating the ways
> > of getting max efficiency from them.
>
> But there's little or no value in it.
> You don't get the max
> efficiency out of a condensing boiler
> by pairing it with a heat bank,
> because it has to run hotter than if
> you simply let it run the radiators
> directly - when it can drop down as low as 50/30.
You can have a DHW only heat bank on mains pressure DHW and still have the
condensing boiler on the rads if you want. A condenser with 22C delta T
will work very efficient on a heat bank as it never operates a low
efficiency at any time. "Overall" more efficient.
> If you use the heatbank only in
> connection with producing hot water,
> it does nothing that you can't achieve
> much more simply by having a HW
> cylinder 25% larger than the equivalent heatbank.
A heat bank can be a lot "smaller" than any unvented cylinder when you
combine the boiler and heat banks outputs. Also it can have no overflow
too.
> If you want to pair a conventional boiler
> with a peak efficiency of 80
> degrees with a heatbank, that may be
> a different discussion.
You didn't read again. A conventional boiler can maintain efficiencies of
90% when coupled to a heat bank. When the Powermax was a thermal store (now
an unvented cylinder) it was the only non-condensing unit that entered the
efficiency bands of the condensing boilers in SEDBUK database. And there
was still lots of room for efficiency improvements in that unit too. And
that is at seasonal efficiencies.
abuse-imm@easy.com IMM
> Sorry,
> I didn't mean to spark the
> Andy/IMM debate again.
Not a debate. Me attempting educate the man.
> It's just that that hot air doesn't supply
> the bathroom downstairs or
> another bathroom with sink & shower
> and 2 more rooms upstairs since it
> was a converted loft.
> I want rid of the hot air heater as it
> sits in the middle of the house
> and the flue cuts straight through
> the room upstairs.
So space saving is the key point?
> I would have liked to have sited
> a new boiler & cylinder in the same
> cupboard as it has a gas supply,
> but as it's in the middle of the house I can't
> plumb a condensate drain or flue it easily.
> Likewise I think I need a pressure/temperature
> relief valve on an unvented cylinder discharging
> outside which I can't do from there either?
> I can't really have any feed/expansion tanks
> for an unvented system upstairs which is why
> I mention heat banks which can incorporate one
> or not need one.
"Some" Heat banks do no require an overflow and are ideal for the centre of
the house fitting. Some Qs: Are you to remove the warm-air cupboard? Is it
big enough for a boiler and warm-air unit with a flue up to the roof?
You talk about put a cylinder in the cupboard, which gains nothing. Is it
really house space you want to claw back? Where is the Main multi-point
water heater?
Answer these and I might help you more, otherwise it is going around the
bushes.
Andy Hall
wrote:
>>
>> At 75 degrees you are only storing
>> 25% more energy than if you
>> used the same sized HW cylinder
>> whatever the size. What's the point?
>> You might as well have a condensing
>> boiler and a fast recovery
>> cylinder and done with it.....
>
>You can then have a heat bank that "combines" the heat of the store "and"
>the boiler and keep the store size down.
It's no different except that the starting temperature is higher.
If you have a fast recovery cylinder and the boiler runs while the
cylinder is being emptied then the stored heat in the water is
combined with that being added by the boiler. The only difference is
that with the store the initial amount of energy stored is a bit
higher.
>
> If you
>> have a HW cylinder or a heat bank and you
>> start taking energy from it but don't replace it
>> until what is stored is almost depleted,
>> then the volume of useful hot water will be
>> less than if the boiler is turned on earlier during the
>> usage of water.
>
>Then you set the controls to bring in the boiler earlier. Simple. I did say
>that, read below.
Which takes us full circle back to where we started. Either you
start the boiler early or late or somewhere in between. The trade off
is between available hot water and efficiency.
>
>> If you wait to start the boiler
>> until the store or cylinder is nearly
>> depleted then there is very
>> little combining effect.
>
>You can:
>
>1. Have two cyl stats that ensure the store is depleted "enough" to bring in
>the boiler for an efficient long burn.
>2. Have the boiler and store "combine" to give high outputs.
>3. A mixture of the two above in that the store will be depleted somewhat
>and then the boiler cuts in.
>
>You have the choice.
Exactly, but you can't have it all as you were implying.
>
>> >One that
>> >will fit under a worktop and still
>> >do the average house.
>>
>> That's complete nonsense.
>
>Please!! There is only so much I will take from a rank amateur. If I say
>so, it is so. If you don't understand then ask, if you still don't then
>just accept.
I never accept things without considering likely validity and this
one, even without checking is obviously out. If you take the
requirement of filling a bath, running a power shower and the amounts
for a sink etc. it works out to about 200 litres of 60 degree water
in a conventional cylinder. Even if you use the calculator on
www.heatweb.com (which is optimistic) to work out a store size, it
comes to 190 litres. A 100 litre store is not going to hack it. I
don't accept the argument that putting in a bigger boiler compensates.
It does to a point, but if you are going to do that you might as well
simply go for a combi and forget the storage all together.
>
>> Fact 2: If you don't begin replacing energy
>> immediately you start to
>> take it out, the supply capacity of the
>> system is reduced compared with if you did.
>
>You can do, if you set the controls to do so. The store acts a "store" and
>a "buffer"
Sure, but then you don't have the efficiency. It's a trade off.
>
>> Dropping the temperature of the store
>> to 75 degrees so that the return
>> to the boiler can be at 55 degrees is
>> purely so that the manufacturer
>> can claim that the boiler is in "condensing
>> mode".
>
>Some boilers can drop below 20c delta T.
Which only makes it worse.
>
>> This is a complete con.
>
>It is not. It is engineering the heat bank to accommodate a condensing
>boiler and create more efficiencies.
Fact 1: To maximise the efficiency of a condensing boiler it must be
run at as low a temperature as possible.
Fact2: To get the best advantage from a heat store in terms of
energy storage it needs to be run at as high a temperature as
possible.
These two are contradictory and so a compromise has to be used.
If the store wer run at 60 degrees there would be no point in having
it since it would be the same as a normal cylinder. The specific
figure of 75 degrees has no basis in terms of achieving either the
storage or the efficiency goal and is chosen only so that it can be
said that the boiler is condensing. It's misleading. The user
might as well run the thing at 82 and have the storage advantage.
>
>You should have understood heat banks, how they work and how you can
>accomodate one to suit your needs, not look at O level phyics books. You
>failed.
This is actually first form grammar school science. I know you would
like to make it more complicated and add mystique, but there is none
to be added - it's simply the relationship between the mass of the
water, its specific heat and the temperature rise or fall.
>
.
>>
>> But there's little or no value in it.
>> You don't get the max
>> efficiency out of a condensing boiler
>> by pairing it with a heat bank,
>> because it has to run hotter than if
>> you simply let it run the radiators
>> directly - when it can drop down as low as 50/30.
>
>You can have a DHW only heat bank on mains pressure DHW and still have the
>condensing boiler on the rads if you want.
That would b sensible.
>A condenser with 22C delta T
>will work very efficient on a heat bank as it never operates a low
>efficiency at any time. "Overall" more efficient.
That I don't buy. In driving a heatbank, certainly an indirect one,
it will have to operate at high temperature, the same as for a fast
recovery cylinder
>
>> If you use the heatbank only in
>> connection with producing hot water,
>> it does nothing that you can't achieve
>> much more simply by having a HW
>> cylinder 25% larger than the equivalent heatbank.
>
>A heat bank can be a lot "smaller" than any unvented cylinder when you
>combine the boiler and heat banks outputs. Also it can have no overflow
>too.
It can be 25% smaller. Combining happens in both cases.
>
>> If you want to pair a conventional boiler
>> with a peak efficiency of 80
>> degrees with a heatbank, that may be
>> a different discussion.
>
>You didn't read again.
No you didn't. The question was in relation to condensing boilers.
Andy Hall
wrote:
>"Peter Parker" <spi...@no.spam> wrote in message
>news:uvmlav08cj1pvtg1c...@4ax.com...
>
>> Sorry,
>> I didn't mean to spark the
>> Andy/IMM debate again.
>
>Not a debate. Me attempting educate the man.
>
Would this be in science, engineering or English grammar?
abuse-imm@easy.com IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> On Sun, 27 Apr 2003 13:22:09 +0100, "IMM" <abuse: abus...@easy.com>
> wrote:
>
> >"Peter Parker" <spi...@no.spam> wrote in message
> >news:uvmlav08cj1pvtg1c...@4ax.com...
> >
> >> Sorry,
> >> I didn't mean to spark the
> >> Andy/IMM debate again.
> >
> >Not a debate. Me attempting educate the man.
> >
> Would this be in science, engineering or English grammar?
In: science, engineering, irony, tango dancing, English and life in general.
abuse-imm@easy.com IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> >> If you wait to start the boiler
> >> until the store or cylinder is nearly
> >> depleted then there is very
> >> little combining effect.
> >
> >You can:
> >
> > 1. Have two cyl stats that ensure the store
> > is depleted "enough" to bring in
> > the boiler for an efficient long burn.
> > 2. Have the boiler and store "combine"
> > to give high outputs.
> > 3. A mixture of the two above in that the
> > store will be depleted somewhat
> > and then the boiler cuts in.
> >
> >You have the choice.
>
> Exactly, but you can't have it all as
> you were implying.
You can. You can even switch between the two main modes above if you want
to. Just a simple switch:
1. Have two cyl stats that ensure the store
is depleted "enough" to bring in
the boiler for an efficient long burn.
2. Have the boiler and store "combine"
to give high outputs.
> >> Fact 2: If you don't begin replacing energy
> >> immediately you start to
> >> take it out, the supply capacity of the
> >> system is reduced compared with if you did.
> >
> >You can do, if you set the controls to do so.
> >The store acts a "store" and a "buffer"
>
> Sure, but then you don't have the efficiency. It's a trade off.
No it is not. The efficiency is still very high.
> >> Dropping the temperature of the store
> >> to 75 degrees so that the return
> >> to the boiler can be at 55 degrees is
> >> purely so that the manufacturer
> >> can claim that the boiler is in "condensing
> >> mode".
> >
> >Some boilers can drop below 20c delta T.
>
> Which only makes it worse.
Sorry, above 20C, such as 22 or 24.
> Fact 1: To maximise the efficiency
> of a condensing boiler it must be
> run at as low a temperature as possible.
This true. But when coupled to a normal rad system much of the time it is
running in a high temp inefficient mode.
> Fact2: To get the best advantage
> from a heat store in terms of
> energy storage it needs to be run
> at as high a temperature as
> possible.
Not true. You size the store to suit many factors.
> These two are contradictory
one is not true so irrelevant.
> >You should have understood heat
> >banks, how they work and how you can
> >accomodate one to suit your needs,
> >not look at O level phyics books. You
> >failed.
>
> This is actually first form grammar school
> science.
I was never taught about heat banks at school.
> That would b sensible.
In some situations, yes.
> >A condenser with 22C delta T
> >will work very efficient on a heat
> >bank as it never operates a low
> >efficiency at any time. "Overall" more efficient.
>
> That I don't buy.
You will just have to accept it.
geoff
<abuse@?.?.com.invalid> writes
--
geoff
Andy Hall
wrote:
>>
>> Exactly, but you can't have it all as
>> you were implying.
>
>You can. You can even switch between the two main modes above if you want
>to. Just a simple switch:
>
>1. Have two cyl stats that ensure the store
> is depleted "enough" to bring in
> the boiler for an efficient long burn.
>2. Have the boiler and store "combine"
> to give high outputs.
In other words, a trade off.
>
>> >> Fact 2: If you don't begin replacing energy
>> >> immediately you start to
>> >> take it out, the supply capacity of the
>> >> system is reduced compared with if you did.
>> >
>> >You can do, if you set the controls to do so.
>> >The store acts a "store" and a "buffer"
>>
>> Sure, but then you don't have the efficiency. It's a trade off.
>
>No it is not. The efficiency is still very high.
Depends on your definition of very high....
>
>> >> Dropping the temperature of the store
>> >> to 75 degrees so that the return
>> >> to the boiler can be at 55 degrees is
>> >> purely so that the manufacturer
>> >> can claim that the boiler is in "condensing
>> >> mode".
>> >
>> >Some boilers can drop below 20c delta T.
>>
>> Which only makes it worse.
>
>Sorry, above 20C, such as 22 or 24.
This is more of the same - playing games with numbers.
>
>> Fact 1: To maximise the efficiency
>> of a condensing boiler it must be
>> run at as low a temperature as possible.
>
>This true. But when coupled to a normal rad system much of the time it is
>running in a high temp inefficient mode.
You just said that the temperature that we would be talking about here
(75+) was still very efficient.
If you read the original post, it was for the replacement of a hot air
system - i.e. new radiators. With this in mind, it is possible to
size the radiators larger so that there is enough heat output at lower
temperatures and thus to improve condensing boiler efficiency.
>
>> Fact2: To get the best advantage
>> from a heat store in terms of
>> energy storage it needs to be run
>> at as high a temperature as
>> possible.
>
>Not true. You size the store to suit many factors.
Of course it's true. The main point of a heat bank is to be able to
store more energy than can be achieved in a conventional cylinder of
the same size or to store the same amount in a smaller size. The
closer the temperatures are, the less the advantage.
>
>
>> >A condenser with 22C delta T
>> >will work very efficient on a heat
>> >bank as it never operates a low
>> >efficiency at any time. "Overall" more efficient.
>>
>> That I don't buy.
>
>You will just have to accept it.
>
>
On the information that you have provided, I don't think that's very
likely, do you?
abuse-imm@easy.com IMM
"geoff" <ge...@ntlworld.com> wrote in message
news:JgbM0IZ7...@81.100.119.82...
I am brilliant at English too.
abuse-imm@easy.com IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> On Mon, 28 Apr 2003 10:44:18 +0100, "IMM" <abuse: abus...@easy.com>
> wrote:
>
>
> >>
> >> Exactly, but you can't have it all as
> >> you were implying.
> >
> >You can. You can even switch between the two main modes above if you
want
> >to. Just a simple switch:
> >
> >1. Have two cyl stats that ensure the store
> > is depleted "enough" to bring in
> > the boiler for an efficient long burn.
> >2. Have the boiler and store "combine"
> > to give high outputs.
>
> In other words, a trade off.
Uh!! NO!!! Yoiu have the choice of operation. Very simple.
> >> >> Fact 2: If you don't begin replacing energy
> >> >> immediately you start to
> >> >> take it out, the supply capacity of the
> >> >> system is reduced compared with if you did.
> >> >
> >> >You can do, if you set the controls to do so.
> >> >The store acts a "store" and a "buffer"
> >>
> >> Sure, but then you don't have the efficiency. It's a trade off.
> >
> >No it is not. The efficiency is still very high.
>
> Depends on your definition of very high....
About the highest you will get.
> >> >> Dropping the temperature of the store
> >> >> to 75 degrees so that the return
> >> >> to the boiler can be at 55 degrees is
> >> >> purely so that the manufacturer
> >> >> can claim that the boiler is in "condensing
> >> >> mode".
> >> >
> >> >Some boilers can drop below 20c delta T.
> >>
> >> Which only makes it worse.
> >
> >Sorry, above 20C, such as 22 or 24.
>
> This is more of the same - playing games with numbers.
NO!!! Making it more efficient.
> >> Fact 1: To maximise the efficiency
> >> of a condensing boiler it must be
> >> run at as low a temperature as possible.
> >
> >This true. But when coupled to a normal
> >rad system much of the time it is
> >running in a high temp inefficient mode.
>
> You just said that the temperature that we
> would be talking about here
> (75+) was still very efficient.
Please read again: "This true. But when coupled to a normal rad system much
of the time it is running in a high temp inefficient mode."
> If you read the original post, it
> was for the replacement of a hot air
> system - i.e. new radiators. With
> this in mind, it is possible to
> size the radiators larger so that there
> is enough heat output at lower
> temperatures and thus to improve
> condensing boiler efficiency.
This is possible. But, the DHW can be a heat bank. Or cheaper still, use an
"integrated" heat bank (DHW & CH) and use a cheaper regular boiler, which
will give efficiencies.
> >> Fact2: To get the best advantage
> >> from a heat store in terms of
> >> energy storage it needs to be run
> >> at as high a temperature as
> >> possible.
> >
> >Not true. You size the store to suit many factors.
>
> Of course it's true.
You have been told, no it is not!
> The main point of a heat bank
> is to be able to store more
> energy than can be achieved
> in a conventional cylinder of
> the same size
No it is not. There are many points about heat banks with no principal
point.
> >> >A condenser with 22C delta T
> >> >will work very efficient on a heat
> >> >bank as it never operates a low
> >> >efficiency at any time. "Overall" more efficient.
> >>
> >> That I don't buy.
> >
> >You will just have to accept it.
> On the information that you have
> provided, I don't think that's very
> likely, do you?
Very likely.
You missed out. You should have gone to a heat bank and used a cheap
non-modulating condensing boiler. Great efficiencies, cheaper capital cost,
etc, etc.
BTW, the energy white paper of last month, indicates that only boilers of
SEDBUK bands A & B will be accepted for sale in a few years time. Then only
condensing and no-flame boilers will be available.
Andy Hall
wrote:
>> >
>> >You can. You can even switch between the two main modes above if you
>want
>> >to. Just a simple switch:
>> >
>> >1. Have two cyl stats that ensure the store
>> > is depleted "enough" to bring in
>> > the boiler for an efficient long burn.
>> >2. Have the boiler and store "combine"
>> > to give high outputs.
>>
>> In other words, a trade off.
>
>Uh!! NO!!! Yoiu have the choice of operation. Very simple.
Black is clearly white today.
>
>> >> >> Fact 2: If you don't begin replacing energy
>> >> >> immediately you start to
>> >> >> take it out, the supply capacity of the
>> >> >> system is reduced compared with if you did.
>> >> >
>> >> >You can do, if you set the controls to do so.
>> >> >The store acts a "store" and a "buffer"
>> >>
>> >> Sure, but then you don't have the efficiency. It's a trade off.
>> >
>> >No it is not. The efficiency is still very high.
>>
>> Depends on your definition of very high....
>
>About the highest you will get.
Not from a condensor which was the subject under discussion since it
is operating above optimal temperatures.
>
>> >> >> Dropping the temperature of the store
>> >> >> to 75 degrees so that the return
>> >> >> to the boiler can be at 55 degrees is
>> >> >> purely so that the manufacturer
>> >> >> can claim that the boiler is in "condensing
>> >> >> mode".
>> >> >
>> >> >Some boilers can drop below 20c delta T.
>> >>
>> >> Which only makes it worse.
>> >
>> >Sorry, above 20C, such as 22 or 24.
>>
>> This is more of the same - playing games with numbers.
>
>NO!!! Making it more efficient.
But still nowhere near optimal conditions.
>
>>
>> You just said that the temperature that we
>> would be talking about here
>> (75+) was still very efficient.
>
>Please read again: "This true. But when coupled to a normal rad system much
>of the time it is running in a high temp inefficient mode."
We're talking about a new installation where it would be possible to
size radiators for lower temperatures.
>
>> If you read the original post, it
>> was for the replacement of a hot air
>> system - i.e. new radiators. With
>> this in mind, it is possible to
>> size the radiators larger so that there
>> is enough heat output at lower
>> temperatures and thus to improve
>> condensing boiler efficiency.
>
>This is possible. But, the DHW can be a heat bank. Or cheaper still, use an
>"integrated" heat bank (DHW & CH) and use a cheaper regular boiler, which
>will give efficiencies.
But we're talking about a condensing boiler, used efficiently and the
heatbank for HW only.
>
>> >> Fact2: To get the best advantage
>> >> from a heat store in terms of
>> >> energy storage it needs to be run
>> >> at as high a temperature as
>> >> possible.
>> >
>> >Not true. You size the store to suit many factors.
>>
>> Of course it's true.
>
>You have been told, no it is not!
Then that tells me for sure that it is.
>
>> The main point of a heat bank
>> is to be able to store more
>> energy than can be achieved
>> in a conventional cylinder of
>> the same size
>
>No it is not. There are many points about heat banks with no principal
>point.
There are many points about cylinders as well but this is the
principal difference.
>
>> >> >A condenser with 22C delta T
>> >> >will work very efficient on a heat
>> >> >bank as it never operates a low
>> >> >efficiency at any time. "Overall" more efficient.
>> >>
>> >> That I don't buy.
>> >
>> >You will just have to accept it.
>
>> On the information that you have
>> provided, I don't think that's very
>> likely, do you?
>
>Very likely.
You must be somewhat naive.
>
>You missed out. You should have gone to a heat bank and used a cheap
>non-modulating condensing boiler. Great efficiencies, cheaper capital cost,
>etc, etc.
No I shouldn't. For my application the complexity outweighed the
advantage, not that we were talking about that particularly anyway.
>
>BTW, the energy white paper of last month, indicates that only boilers of
>SEDBUK bands A & B will be accepted for sale in a few years time. Then only
>condensing and no-flame boilers will be available.
>
>
It will be interesting to see how storage systems can be used to make
the most of that. The obvious way will be larger volumes at lower
temperatures to better match boiler behaviour.
abuse-imm@easy.com IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> >> >You can. You can even switch between the
> >> >two main modes above if you
> >> >want to. Just a simple switch:
> >> >
> >> >1. Have two cyl stats that ensure the store
> >> > is depleted "enough" to bring in
> >> > the boiler for an efficient long burn.
> >> >2. Have the boiler and store "combine"
> >> > to give high outputs.
> >>
> >> In other words, a trade off.
> >
> >Uh!! NO!!! You have the choice of operation. Very simple.
>
> Black is clearly white today.
Then clear the sleep from your eyes.
> >> >> >> Fact 2: If you don't begin replacing energy
> >> >> >> immediately you start to
> >> >> >> take it out, the supply capacity of the
> >> >> >> system is reduced compared with if you did.
> >> >> >
> >> >> >You can do, if you set the controls to do so.
> >> >> >The store acts a "store" and a "buffer"
> >> >>
> >> >> Sure, but then you don't have the efficiency. It's a trade off.
> >> >
> >> >No it is not. The efficiency is still very high.
> >>
> >> Depends on your definition of very high....
> >
> >About the highest you will get.
>
> Not from a condensor which was
> the subject under discussion since it
> is operating above optimal temperatures.
You have this thing about condensers. A no-flame boiler mated to a heat
bank gives brilliant efficiencies. a regular boiler mated to one also gets
the best running from it.
> >> >> >> Dropping the temperature of the store
> >> >> >> to 75 degrees so that the return
> >> >> >> to the boiler can be at 55 degrees is
> >> >> >> purely so that the manufacturer
> >> >> >> can claim that the boiler is in "condensing
> >> >> >> mode".
> >> >> >
> >> >> >Some boilers can drop below 20c delta T.
> >> >>
> >> >> Which only makes it worse.
> >> >
> >> >Sorry, above 20C, such as 22 or 24.
> >>
> >> This is more of the same - playing games with numbers.
> >
> >NO!!! Making it more efficient.
>
> But still nowhere near optimal conditions.
Yes it is.
> >> You just said that the temperature that we
> >> would be talking about here
> >> (75+) was still very efficient.
> >
> >Please read again: "This true. But when
> >coupled to a normal rad system much
> >of the time it is running in a high temp inefficient mode."
>
> We're talking about a new installation where
> it would be possible to size radiators for lower
> temperatures.
That only makes matters better a little.
> >> If you read the original post, it
> >> was for the replacement of a hot air
> >> system - i.e. new radiators. With
> >> this in mind, it is possible to
> >> size the radiators larger so that there
> >> is enough heat output at lower
> >> temperatures and thus to improve
> >> condensing boiler efficiency.
> >
> >This is possible. But, the DHW can
> >be a heat bank. Or cheaper still, use an
> >"integrated" heat bank (DHW & CH) and
> >use a cheaper regular boiler, which
> >will give efficiencies.
>
> But we're talking about a condensing
> boiler,
You are. I am taking about the most efficient setup in which a boiler is
only one point.
> >> >> Fact2: To get the best advantage
> >> >> from a heat store in terms of
> >> >> energy storage it needs to be run
> >> >> at as high a temperature as
> >> >> possible.
> >> >
> >> >Not true. You size the store to suit many factors.
> >>
> >> Of course it's true.
> >
> >You have been told, no it is not!
>
> Then that tells me for sure that it is.
From where do you gain this aricle of faith?
> >> The main point of a heat bank
> >> is to be able to store more
> >> energy than can be achieved
> >> in a conventional cylinder of
> >> the same size
> >
> >No it is not. There are many points
> >about heat banks with no principal
> >point.
>
> There are many points about cylinders
> as well but this is the principal difference.
?????
> >> >> >A condenser with 22C delta T
> >> >> >will work very efficient on a heat
> >> >> >bank as it never operates a low
> >> >> >efficiency at any time. "Overall" more efficient.
> >> >>
> >> >> That I don't buy.
> >> >
> >> >You will just have to accept it.
> >
> >> On the information that you have
> >> provided, I don't think that's very
> >> likely, do you?
> >
> >Very likely.
>
> You must be somewhat naive.
You clearly have experience of HVAC whatsoever.
> >You missed out. You should have
> >gone to a heat bank and used a cheap
> >non-modulating condensing boiler.
> >Great efficiencies, cheaper capital cost,
> >etc, etc.
>
> No I shouldn't. For my application
> the complexity outweighed the
> advantage, not that we were talking
> about that particularly anyway.
complexity? You know little. A heat bank does not have high pressure
regulating controls. the boiler needed be only a cheap, simple, regular or
condensing boiler or better still a no-flame boiler. No super expensive,
modulating, computer controlled boilers at all need be used.
> >BTW, the energy white paper of last
> >month, indicates that only boilers of
> >SEDBUK bands A & B will be accepted
> >for sale in a few years time. Then only
> >condensing and no-flame boilers will be available.
> It will be interesting to see how storage
> systems can be used to make
> the most of that. The obvious way will
> be larger volumes at lower
> temperatures to better match boiler behaviour.
You are obviously referring to condensing boilers. No-flame boilers will
enter more, especially in flats, as they have no plume and can still operate
efficiently at high water temps. A no-flame with heat bank gives excellent
benefits all around.
Simple condensing boilers mated to heat banks will give high efficiencies.
Makers may go back to the original idea of the Powermax models of thermal
store (now heat banks) and high efficiency regular boilers. A regular
boiler will not make band B, mated with a heat bank all in one case (CPSU)
it will (heat banks promote efficient boiler operation). Then they can just
get into sedbuk band B with some tweaking.
Andy Hall
wrote:
>
>You have this thing about condensers. A no-flame boiler mated to a heat
>bank gives brilliant efficiencies. a regular boiler mated to one also gets
>the best running from it.
I don't have any "things". Condensing boilers were part of the
original subject. You introduced all the other obfuscation.
>
>> >> >> >> Dropping the temperature of the store
>> >> >> >> to 75 degrees so that the return
>> >> >> >> to the boiler can be at 55 degrees is
>> >> >> >> purely so that the manufacturer
>> >> >> >> can claim that the boiler is in "condensing
>> >> >> >> mode".
>> >> >> >
>> >> >> >Some boilers can drop below 20c delta T.
>> >> >>
>> >> >> Which only makes it worse.
>> >> >
>> >> >Sorry, above 20C, such as 22 or 24.
>> >>
>> >> This is more of the same - playing games with numbers.
>> >
>> >NO!!! Making it more efficient.
>>
>> But still nowhere near optimal conditions.
>
>Yes it is.
I'm not going to play pantomime games. Just take a look at condensor
boiler data sheets of efficiency vs. temperature. These all show an
increased rate of change below the dew point, therefore it follow that
it makes sense to operate on that part of the curve if possible.
This can happen with direct coupling to appropriately sized radiators
and underfloor systems for heating. It won't be achieved with a heat
store if used for space heating. It also won't be optimal with a
heat store or a conventional cylinder used for DHW.
>
>> We're talking about a new installation where
>> it would be possible to size radiators for lower
>> temperatures.
>
>That only makes matters better a little.
It makes a substantial difference - look at the performance graphs and
figures.
>>
>> But we're talking about a condensing
>> boiler,
>
>You are. I am taking about the most efficient setup in which a boiler is
>only one point.
This was the original question.
>
>> >
>> >You have been told, no it is not!
>>
>> Then that tells me for sure that it is.
>
>From where do you gain this aricle of faith?
From the University that I originally attended and the one that I
continue to attend called the University of Life.
Put simply, if somebody makes a point without being able to justify
it, but with increasing fervour, there is a higher than average chance
that it is wrong.
>
>
>You clearly have experience of HVAC whatsoever.
You're certainly correct there - from researching, designing properly
and implementing, finally to achieve results as required and
predicted.
>
>
>
>Simple condensing boilers mated to heat banks will give high efficiencies.
Not for space heating.
>Makers may go back to the original idea of the Powermax models of thermal
>store (now heat banks) and high efficiency regular boilers. A regular
>boiler will not make band B, mated with a heat bank all in one case (CPSU)
>it will (heat banks promote efficient boiler operation). Then they can just
>get into sedbuk band B with some tweaking.
>
Then they will have to employ Dr Who as chief designer. CPSUs may be
able to be accomodated in new build property, but are less easy to
accomodate for refit purposes because of the size.
abuse-imm@easy.com IMM
> >You have this thing about condensers.
> >A no-flame boiler mated to a heat
> >bank gives brilliant efficiencies. a regular
> >boiler mated to one also gets
> >the best running from it.
>
> I don't have any "things". Condensing
> boilers were part of the
> original subject. You introduced all
> the other obfuscation.
The original poster mentioned heat banks and condensers. nothing obtuse at
all.
> I'm not going to play pantomime games.
> Just take a look at condensor
> boiler data sheets of efficiency vs.
> temperature. These all show an
> increased rate of change below the
> dew point, therefore it follow that
> it makes sense to operate on that
> part of the curve if possible.
> This can happen with direct coupling
> to appropriately sized radiators
> and underfloor systems for heating.
Amd to a thermal store. But a no-flame boiler is a better option than a
condenser when used with a heat bank. The better regular boilers also give
high efficiencies too. don't go by SEDBUK, go by makers data on peak
efficiencies.
> It won't be achieved with a heat
> store if used for space heating.
You fail to note that, apart from underfloor heating, much of the time a
condensing boiler will be operating at a high inefficient temperature.
> It also won't be optimal with a
> heat store or a conventional cylinder
> used for DHW.
nonsense.
> >> We're talking about a new installation where
> >> it would be possible to size radiators for lower
> >> temperatures.
> >
> >That only makes matters better a little.
>
> It makes a substantial difference - look
> at the performance graphs and
> figures.
As I say: "apart from underfloor heating, much of the time a condensing
boiler will be operating at a high inefficient temperature. Saying that
they are more efficient than regular boilers as they have larger heat
exchangers.
> >> But we're talking about a condensing
> >> boiler,
> >
> >You are. I am taking about the most
> >efficient setup in which a boiler is
> >only one point.
>
> This was the original question.
It wasn't.
> >> >You have been told, no it is not!
> >>
> >> Then that tells me for sure that it is.
> >
> >From where do you gain this aricle of faith?
>
> From the University that I originally
> attended
What course? HVAC? if not then it is no better than these con CORGI
courses.
> and the one that I
> continue to attend called the University of Life.
Some uni, does it teach the tango?
> >You clearly have experience of HVAC whatsoever.
>
> You're certainly correct there
Thank you!!!
>- from researching, designing properly
> and implementing, finally to achieve
> results as required and predicted.
In HVAC?
> >Simple condensing boilers mated to
> >heat banks will give high efficiencies.
>
> Not for space heating.
overall they will.
> >Makers may go back to the original idea of the Powermax models of thermal
> >store (now heat banks) and high efficiency regular boilers. A regular
> >boiler will not make band B, mated with a heat bank all in one case
(CPSU)
> >it will (heat banks promote efficient boiler operation). Then they can
just
> >get into sedbuk band B with some tweaking.
>
> Then they will have to employ Dr Who as chief designer. CPSUs may be
> able to be accomodated in new build property, but are less easy to
> accomodate for refit purposes because of the size.
How silly. Have you see the size of the Glendhill? of course you have not!
Andy Hall
wrote:
>
>The original poster mentioned heat banks and condensers. nothing obtuse at
>all.
So why introduce all the other stuff
>
>> I'm not going to play pantomime games.
>> Just take a look at condensor
>> boiler data sheets of efficiency vs.
>> temperature. These all show an
>> increased rate of change below the
>> dew point, therefore it follow that
>> it makes sense to operate on that
>> part of the curve if possible.
>> This can happen with direct coupling
>> to appropriately sized radiators
>> and underfloor systems for heating.
>
>Amd to a thermal store.
No. Refer to http://www.keston.co.uk/downloads/pdf/cel25-b.pdf
which is typical of a condensing boiler.
If you look at the graph, you will note that the published efficiency
changes from about 88% at the 52 degree dew point to about 86% at 70
degrees - the operating range to charge a thermal store or a HW
cylinder.
Between 52 and 32 degrees it has gone from 88% to 95%.
This is the operating range for a new radiator system sized for
condensing boiler operation or for UFH.
>
>> It won't be achieved with a heat
>> store if used for space heating.
>
>You fail to note that, apart from underfloor heating, much of the time a
>condensing boiler will be operating at a high inefficient temperature.
It won't be if driving radiators sized to give enough output at lower
temperatures. In that case, the only time would be a HW cylinder or
thermal store heating cycle. The rest of the time, it can be
modulated right down during much of the year.
>
>> It also won't be optimal with a
>> heat store or a conventional cylinder
>> used for DHW.
>
>nonsense.
I've just demonstrated that my point is correct.
>
>> >> We're talking about a new installation where
>> >> it would be possible to size radiators for lower
>> >> temperatures.
>> >
>> >That only makes matters better a little.
>>
>> It makes a substantial difference - look
>> at the performance graphs and
>> figures.
>
>As I say: "apart from underfloor heating, much of the time a condensing
>boiler will be operating at a high inefficient temperature. Saying that
>they are more efficient than regular boilers as they have larger heat
>exchangers.
Say it if you like but demonstrably it is wrong.
>
>> and the one that I
>> continue to attend called the University of Life.
>
>Some uni, does it teach the tango?
>
>> >You clearly have experience of HVAC whatsoever.
>>
>> You're certainly correct there
>
>Thank you!!!
>
>>- from researching, designing properly
>> and implementing, finally to achieve
>> results as required and predicted.
>
>In HVAC?
I know that you would like the subject to be complicated, but in terms
of domestic systems it is really very simple.
>
>> >Makers may go back to the original idea of the Powermax models of thermal
>> >store (now heat banks) and high efficiency regular boilers. A regular
>> >boiler will not make band B, mated with a heat bank all in one case
>(CPSU)
>> >it will (heat banks promote efficient boiler operation). Then they can
>just
>> >get into sedbuk band B with some tweaking.
>>
>> Then they will have to employ Dr Who as chief designer. CPSUs may be
>> able to be accomodated in new build property, but are less easy to
>> accomodate for refit purposes because of the size.
>
>How silly. Have you see the size of the Glendhill? of course you have not!
>
>
Yes.
Gulfstream 2000. 1300mm high and footprint of 595 each way and need
1850 of cupboard height.
Boilermate - no boiler - 1140 - 1550 high by 595 square.
Pretty big for any useful capacity.
geoff
<abuse@?.?.com.invalid> writes
>
>> >> >
>> >> >Not a debate. Me attempting educate the man.
>> >> >
>> >> Would this be in science, engineering or English grammar?
>> >
>> >In: science, engineering, irony, tango dancing, English and life in
>general.
>> >
>> >
>> I noticed you missed the word "grammar" out
>
>I am brilliant at English too.
Wel yor trak rekord speeks for isselft
--
geoff
abuse-imm@easy.com IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> >The original poster mentioned heat banks and condensers. nothing obtuse
at
> >all.
>
> So why introduce all the other stuff
He needs to know the complete picture, not an expensive slanted look as you
give. He can use a heat bank and a cheap simple boiler and gain high
efficiency and mains pressure hot water that will virtually not run out.
Brilliant!
> >> I'm not going to play pantomime games.
> >> Just take a look at condensor
> >> boiler data sheets of efficiency vs.
> >> temperature. These all show an
> >> increased rate of change below the
> >> dew point, therefore it follow that
> >> it makes sense to operate on that
> >> part of the curve if possible.
> >> This can happen with direct coupling
> >> to appropriately sized radiators
> >> and underfloor systems for heating.
> >
> >And to a thermal store.
>
> No. Refer to http://www.keston.co.uk/downloads/pdf/cel25-b.pdf
> which is typical of a condensing boiler.
You missed the plot.
> If you look at the graph, you will note that the published efficiency
> changes from about 88% at the 52 degree dew point to about 86% at 70
> degrees - the operating range to charge a thermal store or a HW
> cylinder.
>
> Between 52 and 32 degrees it has gone from 88% to 95%.
> This is the operating range for a new radiator system sized for
> condensing boiler operation or for UFH.
But!! When the rad system is warmed up the return temp,mp do too, to rather
inefficient levels. So this 88-95% is not constant.
> >> It won't be achieved with a heat
> >> store if used for space heating.
> >
> >You fail to note that, apart from
> >underfloor heating, much of the time a
> >condensing boiler will be operating at
> >a high inefficient temperature.
>
> It won't be if driving radiators sized to
> give enough output at lower
> temperatures. In that case, the only
> time would be a HW cylinder or
> thermal store heating cycle. The rest
> of the time, it can be
> modulated right down during much of the year.
A heat bank can have different heat ranges at different levels of the
cylinder. So at the lower levels/temp range, this could be governed by the
outside temperature supplying the CH, cascading into a condensing boiler
operating at a much lower high efficient return temp. Simple.
When the top half of the heat bank calls for heat for DHW, the boiler goes
to maximum to supply, when satisfied it then supplies the lower half to the
outside weather compensator dictates.
> >> It also won't be optimal with a
> >> heat store or a conventional cylinder
> >> used for DHW.
> >
> >nonsense.
>
> I've just demonstrated that my point is correct.
You didn't.
> >> and the one that I
> >> continue to attend called the University of Life.
> >
> >Some uni, does it teach the tango?
> >
> >> >You clearly have experience of HVAC whatsoever.
> >>
> >> You're certainly correct there
> >
> >Thank you!!!
> >
> >>- from researching, designing properly
> >> and implementing, finally to achieve
> >> results as required and predicted.
> >
> >In HVAC?
>
> I know that you would like the subject
> to be complicated, but in terms
> of domestic systems it is really very simple.
Then why can't you grasp it? ths research you werte on about. Well you
failed on that.
> Gulfstream 2000. 1300mm high and footprint of 595 each way and need
> 1850 of cupboard height.
>
> Boilermate - no boiler - 1140 - 1550 high by 595 square.
>
> Pretty big for any useful capacity.
Performance is the word, NOT capacity. DPS have the GVX which is very small
and belts out the flowrates by combining the energy in the store and the
boiler. Brilliant!
abuse-imm@easy.com IMM
You need to learn to spoke proper.
Andy Hall
wrote:
>>
>> So why introduce all the other stuff
>
>He needs to know the complete picture, not an expensive slanted look as you
>give. He can use a heat bank and a cheap simple boiler and gain high
>efficiency and mains pressure hot water that will virtually not run out.
>Brilliant!
Since when was a Celsius expensive?
>
>> >> I'm not going to play pantomime games.
>> >> Just take a look at condensor
>> >> boiler data sheets of efficiency vs.
>> >> temperature. These all show an
>> >> increased rate of change below the
>> >> dew point, therefore it follow that
>> >> it makes sense to operate on that
>> >> part of the curve if possible.
>> >> This can happen with direct coupling
>> >> to appropriately sized radiators
>> >> and underfloor systems for heating.
>> >
>> >And to a thermal store.
>>
>> No. Refer to http://www.keston.co.uk/downloads/pdf/cel25-b.pdf
>> which is typical of a condensing boiler.
>
>You missed the plot.
You mean the obfuscation plot? I prefer to stick to the main one.
>
>> If you look at the graph, you will note that the published efficiency
>> changes from about 88% at the 52 degree dew point to about 86% at 70
>> degrees - the operating range to charge a thermal store or a HW
>> cylinder.
>>
>> Between 52 and 32 degrees it has gone from 88% to 95%.
>> This is the operating range for a new radiator system sized for
>> condensing boiler operation or for UFH.
>
>But!! When the rad system is warmed up the return temp,mp do too, to rather
>inefficient levels. So this 88-95% is not constant.
??? The return temperature may well start low - room temperature.
That's even better. The flow will be at around 20 above that. By
the time the return temperature reaches the required level, the burner
will be modulated down. For a UFH design that would be at around 30
degrees return, and for a typical radiator design optimised for the
purpose it would be 50 at full heat load requirement, less than that
during large parts of the year. For space heating, there is no
reason for anything in excess of 50, so in comparison with running the
same boiler at 75-80, it will be 7 or 8 points more efficient.
>
>> >> It won't be achieved with a heat
>> >> store if used for space heating.
>> >
>> >You fail to note that, apart from
>> >underfloor heating, much of the time a
>> >condensing boiler will be operating at
>> >a high inefficient temperature.
>>
>> It won't be if driving radiators sized to
>> give enough output at lower
>> temperatures. In that case, the only
>> time would be a HW cylinder or
>> thermal store heating cycle. The rest
>> of the time, it can be
>> modulated right down during much of the year.
>
>A heat bank can have different heat ranges at different levels of the
>cylinder.
You mean different temperatures. The phenomenon is called
stratification.
>So at the lower levels/temp range, this could be governed by the
>outside temperature supplying the CH, cascading into a condensing boiler
>operating at a much lower high efficient return temp. Simple.
Unnecessarily complicated when compared with simply driving the
radiators directly from the boiler and adds no value.
>
>When the top half of the heat bank calls for heat for DHW, the boiler goes
>to maximum to supply, when satisfied it then supplies the lower half to the
>outside weather compensator dictates.
This all makes it more pointless because you are reducing the energy
storage capacity for hot water. The effect is that this errs more and
more towards an instant HW system with its limitations.
>>
>> I know that you would like the subject
>> to be complicated, but in terms
>> of domestic systems it is really very simple.
>
>Then why can't you grasp it? ths research you werte on about. Well you
>failed on that.
There's nothing that I haven't already grasped, thanks. There is
nothing complex in any of this.
>
>> Gulfstream 2000. 1300mm high and footprint of 595 each way and need
>> 1850 of cupboard height.
>>
>> Boilermate - no boiler - 1140 - 1550 high by 595 square.
>>
>> Pretty big for any useful capacity.
>
>Performance is the word, NOT capacity. DPS have the GVX which is very small
>and belts out the flowrates by combining the energy in the store and the
>boiler. Brilliant!
>
So round we go again to a combi with a little store in a box. Hardly
revolutionary. We already saw, and demonstrated that this product is
too small for other than a small house or flat. Go to their web site
and add it up.
It doesn't matter how much you want to complicate the story but:
A) Energy out = energy in + energy stored
B) Heat gained or lost = mass x specific heat x temperature rise or
fall.
You can waffle as much as you like but those are the two
incontrovertible facts.
abuse-imm@easy.com IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> On Tue, 29 Apr 2003 23:43:02 +0100, "IMM" <abuse: abus...@easy.com>
> wrote:
>
> >>
> >> So why introduce all the other stuff
> >
> >He needs to know the complete picture, not an expensive slanted look as
you
> >give. He can use a heat bank and a cheap simple boiler and gain high
> >efficiency and mains pressure hot water that will virtually not run out.
> >Brilliant!
>
> Since when was a Celsius expensive?
A celsius "cannot" be mated to a heat bank or thermal store. A cheap
regular boiler can.
> >> >> I'm not going to play pantomime games.
> >> >> Just take a look at condensor
> >> >> boiler data sheets of efficiency vs.
> >> >> temperature. These all show an
> >> >> increased rate of change below the
> >> >> dew point, therefore it follow that
> >> >> it makes sense to operate on that
> >> >> part of the curve if possible.
> >> >> This can happen with direct coupling
> >> >> to appropriately sized radiators
> >> >> and underfloor systems for heating.
> >> >
> >> >And to a thermal store.
> >>
> >> No. Refer to http://www.keston.co.uk/downloads/pdf/cel25-b.pdf
> >> which is typical of a condensing boiler.
> >
> >You missed the plot.
>
> You mean the obfuscation plot?
> I prefer to stick to the main one.
You don't know what the plot is, to stick to.
> >> If you look at the graph, you will note that the published efficiency
> >> changes from about 88% at the 52 degree dew point to about 86% at 70
> >> degrees - the operating range to charge a thermal store or a HW
> >> cylinder.
> >>
> >> Between 52 and 32 degrees it has gone from 88% to 95%.
> >> This is the operating range for a new radiator system sized for
> >> condensing boiler operation or for UFH.
> >
> >But!! When the rad system is warmed up the return temp,mp do too, to
rather
> >inefficient levels. So this 88-95% is not constant.
>
> ??? The return temperature may well start low - room temperature.
> That's even better. The flow will be at around 20 above that. By
> the time the return temperature reaches the required level, the burner
> will be modulated down. For a UFH design that would be at around 30
> degrees return, and for a typical radiator design optimised for the
> purpose it would be 50 at full heat load requirement, less than that
> during large parts of the year. For space heating, there is no
> reason for anything in excess of 50, so in comparison with running the
> same boiler at 75-80, it will be 7 or 8 points more efficient.
A condenser mated to UFH can be highly efficient as the system runs of low
temps. To get the same high efficiency with rads you require very large
rads which adds even more expense.
> >> >> It won't be achieved with a heat
> >> >> store if used for space heating.
> >> >
> >> >You fail to note that, apart from
> >> >underfloor heating, much of the time a
> >> >condensing boiler will be operating at
> >> >a high inefficient temperature.
> >>
> >> It won't be if driving radiators sized to
> >> give enough output at lower
> >> temperatures. In that case, the only
> >> time would be a HW cylinder or
> >> thermal store heating cycle. The rest
> >> of the time, it can be
> >> modulated right down during much of the year.
> >
> >A heat bank can have different heat ranges
> >at different levels of the cylinder.
> You mean different temperatures.
No read above.
> >So at the lower levels/temp range, this
> >could be governed by the
> >outside temperature supplying the CH,
> >cascading into a condensing boiler
> >operating at a much lower high efficient
> >return temp. Simple.
>
> Unnecessarily complicated when
> compared with simply driving the
> radiators directly from the boiler
> and adds no value.
It is not complicated at all. Also the heat bank can be heated via a solid
fuel boiler as well , and solar panels. The solar gained heat is then used
for CH purposes, which doesn't happen with DHW only solar systems. You can
also have electrical backup of CH and DHW too. Gledhill have the SWITCH to
automatically switch in if the boiler is down. Another great advantage of
heat banks.
> >When the top half of the heat bank
> >calls for heat for DHW, the boiler goes
> >to maximum to supply, when satisfied
> >it then supplies the lower half to the
> >outside weather compensator dictates.
>
> This all makes it more pointless because
> you are reducing the energy
> storage capacity for hot water.
No you don't. You size it suit. Duh!!!
> The effect is that this errs more and
> more towards an instant HW system
> with its limitations.
It doesn't. A heat bank with this specification can be packaged all in one
unit. Then just couple up a cheapish boiler. Simple.
> >> I know that you would like the subject
> >> to be complicated, but in terms
> >> of domestic systems it is really very simple.
> >
> >Then why can't you grasp it? ths research you werte on about. Well you
> >failed on that.
>
> There's nothing that I haven't already grasped, thanks. There is
> nothing complex in any of this.
It is plain you were not ware of what a heat bank could do when you did your
"research". If you asked the right Qs I might have helped you instead of
thinking you knew it all.
> >Performance is the word, NOT capacity.
> >DPS have the GVX which is very small
> >and belts out the flowrates by combining
> >the energy in the store and the
> >boiler. Brilliant!
>
> So round we go again to a combi with
> a little store in a box.
No a heat bank. A combi is all in one box. I know of no combi that
combines the energy of stored water and the burner output.
> Hardly revolutionary.
Read above.
> We already saw, and demonstrated that this product is
> too small for other than a small house or flat.
You can size up if you want to to supply any sized house.
> You can waffle as much as you like
> but those are the two
> incontrovertible facts.
You should read more about heat banks instead of reading O levels physics
books.
Andy Hall
wrote:
>
>"Andy Hall" <an...@hall.nospam> wrote in message
>news:g41uavcnle8ii0fqa...@4ax.com...
>> On Tue, 29 Apr 2003 23:43:02 +0100, "IMM" <abuse: abus...@easy.com>
>> wrote:
>>
>> >>
>> >> So why introduce all the other stuff
>> >
>> >He needs to know the complete picture, not an expensive slanted look as
>you
>> >give. He can use a heat bank and a cheap simple boiler and gain high
>> >efficiency and mains pressure hot water that will virtually not run out.
>> >Brilliant!
>>
>> Since when was a Celsius expensive?
>
>
>A celsius "cannot" be mated to a heat bank or thermal store. A cheap
>regular boiler can.
For an indirect store, which is what the OP would need, there is no
reason why not - it will simply operate in the same way as for a
conventional cylinder.
>
>
>A condenser mated to UFH can be highly efficient as the system runs of low
>temps. To get the same high efficiency with rads you require very large
>rads which adds even more expense.
They do not need to be very large unless the rooms are very large or
the property has high heat loss. The derating factor is 40% for
running at 70/50, which would be for mid-winter -3 temperatures. At
times when it is warmer, which is almost all the year, this level of
output is not needed and the boiler can run at even lower
temperatures.
>
>> >
>> >A heat bank can have different heat ranges
>> >at different levels of the cylinder.
>
>> You mean different temperatures.
>
>No read above.
Heat is a form of energy so there is no concept of "heat ranges", only
temperature ranges.
>
>>
>> Unnecessarily complicated when
>> compared with simply driving the
>> radiators directly from the boiler
>> and adds no value.
>
>It is not complicated at all. Also the heat bank can be heated via a solid
>fuel boiler as well , and solar panels. The solar gained heat is then used
>for CH purposes, which doesn't happen with DHW only solar systems. You can
>also have electrical backup of CH and DHW too. Gledhill have the SWITCH to
>automatically switch in if the boiler is down. Another great advantage of
>heat banks.
This is just getting more complicated and involved and further away
from the original question as you go. Solar and solid fuel were not
even on the agenda. For the OP, the point of a heatbank was mainly
to avoid overflows which are logistically difficult and perhaps to be
able to store a bit more energy to put into the hot water, which was a
point reached several days ago.
>
>> >When the top half of the heat bank
>> >calls for heat for DHW, the boiler goes
>> >to maximum to supply, when satisfied
>> >it then supplies the lower half to the
>> >outside weather compensator dictates.
>>
>> This all makes it more pointless because
>> you are reducing the energy
>> storage capacity for hot water.
>
>No you don't. You size it suit. Duh!!!
You still don't get more out than you put in. One of your claimed
advantages for a heat store is reduction in size vs a conventional
cylinder. Fine, but that only works to the extent that it has water
stored at above 60 degrees. You can't have it both ways at the same
time.
>
>> The effect is that this errs more and
>> more towards an instant HW system
>> with its limitations.
>
>It doesn't. A heat bank with this specification can be packaged all in one
>unit. Then just couple up a cheapish boiler. Simple.
>
If you go for a small store to save space, it stores relatively little
energy. When this runs out, the situation changes to what is, in
effect a boiler indirectly heating a heat exchanger for instant hot
water - a combi with bits in the middle. The smaller the package,
the sooner that happens and then it isn't interesting.
>
>It is plain you were not ware of what a heat bank could do when you did your
>"research". If you asked the right Qs I might have helped you instead of
>thinking you knew it all.
I found out about all that was relevant to my requirements. I didn't
bother to look at putting energy into heat banks via solid fuel or
solar energy because I didn't want to use either of them. The
features of heatbank technology that would therefore be benefits
are then limited to what it fundamentally does which is storing water
at a higher temperature than a cylinder and therefore being able to
provide more energy in the same space.
I never claim to "know it all" on any subject. That would also be
pointless. The important issue is to identify the key points for
making decisions and to stick to them.
>
>> >Performance is the word, NOT capacity.
>> >DPS have the GVX which is very small
>> >and belts out the flowrates by combining
>> >the energy in the store and the
>> >boiler. Brilliant!
>>
>> So round we go again to a combi with
>> a little store in a box.
>
>No a heat bank. A combi is all in one box. I know of no combi that
>combines the energy of stored water and the burner output.
The Baxi Maxflow is an example of such a product. The 55 litre
integral cylinder is depleted when a tap is turned on and the burner
lights to supplement and recharge it. The only difference is that
the water is stored at no more than 60 degrees. Once the energy in
the cylinder is used, which at the manufacturer's suggest 16
litres/min is about 3 mins plus whatever the boiler can add, this
becomes a combi of limited performance.
In essence, this is the same as a boiler connected to a heatbank - all
that changes is the size of the store and the temperature.
>
>> Hardly revolutionary.
>
>Read above.
>
>> We already saw, and demonstrated that this product is
>> too small for other than a small house or flat.
>
>You can size up if you want to to supply any sized house.
Fine, but the size argument is a thin one.
>
>> You can waffle as much as you like
>> but those are the two
>> incontrovertible facts.
>
>You should read more about heat banks instead of reading O levels physics
>books.
>
This is first form.
abuse-imm@easy.com IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> >A celsius "cannot" be mated to a heat bank or thermal store. A cheap
> >regular boiler can.
>
> For an indirect store, which is what the
> OP would need, there is no
> reason why not - it will simply operate
> in the same way as for a
> conventional cylinder.
Yum don't know that he need an indirect yet. A condenser that can have the
load compensation control switched off is the one to go for. I belive Baxi
can.
> >A condenser mated to UFH can be
> >highly efficient as the system runs of low
> >temps. To get the same high efficiency
> >with rads you require very large
> >rads which adds even more expense.
>
> They do not need to be very large
They do and take up more space as well. A no-flame boiler is better.
> >> >A heat bank can have different heat ranges
> >> >at different levels of the cylinder.
> >
> >> You mean different temperatures.
> >
> >No read above.
> >> Unnecessarily complicated when
> >> compared with simply driving the
> >> radiators directly from the boiler
> >> and adds no value.
> >
> >It is not complicated at all. Also the heat bank can be heated via a
solid
> >fuel boiler as well , and solar panels. The solar gained heat is then
used
> >for CH purposes, which doesn't happen with DHW only solar systems. You
can
> >also have electrical backup of CH and DHW too. Gledhill have the SWITCH
to
> >automatically switch in if the boiler is down. Another great advantage
of
> >heat banks.
>
> This is just getting more complicated and involved and further away
> from the original question as you go.
Yet it shows the versitility and efficiency of a heat bank.
> >> >When the top half of the heat bank
> >> >calls for heat for DHW, the boiler goes
> >> >to maximum to supply, when satisfied
> >> >it then supplies the lower half to the
> >> >outside weather compensator dictates.
> >>
> >> This all makes it more pointless because
> >> you are reducing the energy
> >> storage capacity for hot water.
> >
> >No you don't. You size it suit. Duh!!!
>
> You still don't get more out than you put in.
> One of your claimed advantages for a heat
> store is reduction in size vs a conventional
> cylinder. Fine, but that only works to the
> extent that it has water stored at above 60
> degrees.
Not so.
> >> The effect is that this errs more and
> >> more towards an instant HW system
> >> with its limitations.
> >
> >It doesn't. A heat bank with this specification
> >can be packaged all in one
> >unit. Then just couple up a cheapish boiler.
> >Simple.
>
> If you go for a small store to save space,
> it stores relatively little energy.
Not so.
> When this runs out, the situation
> changes to what is, in effect a boiler
> indirectly heating a heat exchanger
> for instant hot water - a combi with
> bits in the middle. The smaller the package,
> the sooner that happens and then it
> isn't interesting.
Once again, you size to suit. You put in a 80 litre cylinder in a
conventional house with 2 baths you will run out of hot water - simple. You
size the store to suite demand (this simple thing is something you can't
figure out as you have repeatedly said this) and they still will be smaller
than unvented cylinders, as you are using all the energy available to you.
the stored hot water and the power of the boiler. The best way to go.
> >It is plain you were not ware of what a
> >heat bank could do when you did your
> >"research". If you asked the right Qs
> >I might have helped you instead of
> >thinking you knew it all.
>
> I found out about all that was relevant
> to my requirements.
You missd a lot.
> The features of heatbank technology
> that would therefore be benefits
> are then limited to what it fundamentally
> does which is storing water
> at a higher temperature than a cylinder
> and therefore being able to
> provide more energy in the same space.
Yet not much higher temps than a cylinder.
> I never claim to "know it all" on any subject.
You do on this one quoting O level school books too.
> >> >Performance is the word, NOT capacity.
> >> >DPS have the GVX which is very small
> >> >and belts out the flowrates by combining
> >> >the energy in the store and the
> >> >boiler. Brilliant!
> >>
> >> So round we go again to a combi with
> >> a little store in a box.
> >
> >No a heat bank. A combi is all in one box.
> >I know of no combi that
> >combines the energy of stored water
> >and the burner output.
>
> The Baxi Maxflow is an example of
> such a product.
Not so. It has an integral unvented cylinder containing "secondary" water.
> The 55 litre integral cylinder is depleted
> when a tap is turned on and the burner
> lights to supplement and recharge it.
The burner replenished the spent hot water. In a heat bank the energy from
the stored hot water "AND" the burner can be put to use "combined". Once
again you talk of what you know little, or nothing, of.
> In essence, this is the same
> as a boiler connected to a heatbank
Not at all. see above.
> >You should read more about heat banks
> >instead of reading O levels physics
> >books.
>
> This is first form.
Heat banks in O levels school books? you are jesting of course.
Andy Hall
wrote:
>
>"Andy Hall" <an...@hall.nospam> wrote in message
>news:vdbvavs9o897vqu91...@4ax.com...
>
>> >A celsius "cannot" be mated to a heat bank or thermal store. A cheap
>> >regular boiler can.
>>
>> For an indirect store, which is what the
>> OP would need, there is no
>> reason why not - it will simply operate
>> in the same way as for a
>> conventional cylinder.
>
>Yum don't know that he need an indirect yet.
We probably do. Go and look back through the thread.
The property is a bungalow with the space that could be used for the
cylinder on the ground floor. It has rooms in the roof -
dormer/chalet style and no space upstairs for tanks.
It is virtually impossible for him to run overflows or discharge pipes
from the cupboard where the cylinder/store could go because it's in
the middle of the house.
Heating is required for rooms in the roof.
So a self contained heat store could be used - e.g. one of DPS's ones
with the small tank in the top, but then that would have to be an
indirect model with the boiler heating a coil in the store. Reason
is that the primary is going to have to run sealed if there is no tank
option in the roof. Radiators running from the store aren't an option
either since they would be above the integral header tank. Either
that or the whole store would have to run pressurised, which is back
to the discharge problem again.
>A condenser that can have the
>load compensation control switched off is the one to go for. I belive Baxi
>can.
In the scenario required this isn't necessary. He can get the best
performance out of the condensing boiler with its controls fully
operational and driving a suitably sized set of radiators, then
driving the store as required.
>
>> >A condenser mated to UFH can be
>> >highly efficient as the system runs of low
>> >temps. To get the same high efficiency
>> >with rads you require very large
>> >rads which adds even more expense.
>>
>> They do not need to be very large
>
>They do and take up more space as well. A no-flame boiler is better.
I was easily able to handle this by swapping radiators without fins to
those with, or doubles where there were singles.
>>
>> This is just getting more complicated and involved and further away
>> from the original question as you go.
>
>Yet it shows the versitility and efficiency of a heat bank.
Versatility, possibly, but only if you need that. Efficiency would
depend on how it's used.
In this case the attraction is the possibility of not needing an
overflow and being able to store energy.
>>
>> You still don't get more out than you put in.
>> One of your claimed advantages for a heat
>> store is reduction in size vs a conventional
>> cylinder. Fine, but that only works to the
>> extent that it has water stored at above 60
>> degrees.
>
>Not so.
Of course it is. If I have a conventional cylinder and store water
in it at 60 degrees, it is precisiely the same amount of energy as if
I had stored it in a thermal store at 60 degrees.
If I store water in the store at 75 degrees then I could reduce the
capacity of the store to 80% of the original size and have stored the
same amount of energy.
>>
>> If you go for a small store to save space,
>> it stores relatively little energy.
>
>Not so.
So where does it store it? The heat storage capacity is directly
proportional to the volume of water.
>
>> When this runs out, the situation
>> changes to what is, in effect a boiler
>> indirectly heating a heat exchanger
>> for instant hot water - a combi with
>> bits in the middle. The smaller the package,
>> the sooner that happens and then it
>> isn't interesting.
>
>Once again, you size to suit. You put in a 80 litre cylinder in a
>conventional house with 2 baths you will run out of hot water - simple. You
>size the store to suite demand (this simple thing is something you can't
>figure out as you have repeatedly said this) and they still will be smaller
>than unvented cylinders, as you are using all the energy available to you.
>the stored hot water and the power of the boiler. The best way to go.
I haven't denied that a heatbank can be smaller than a conventional
cylinder - to be precise 80% of the size if you run it at 75 degrees.
The energy from the boiler can be added whether it's a store or a
cylinder.
I don't believe that for most people, having a 160 litre cylinder vs a
200 litre one in their airing cupboard makes a big difference,
especially when you have to account for the extra pumps, exchangers
and valves needed for a heatbank.
Having mains derived hot water in reasonable volumes, possibly not
needing overflows and being able to DIY would appear to be rather more
attractive.
The notion that a small heatbank that fits under a worktop, even if it
were desirable, can provide enough HW for the average house is
misleading at best. There are no wondrous gains to be had - just
simple proportions between temperatures.
>
>
>> I never claim to "know it all" on any subject.
>
>You do on this one quoting O level school books too.
Please point to where I have mentioned O levels or knowing everything
on the subject.
>
>>
>> The Baxi Maxflow is an example of
>> such a product.
>
>Not so. It has an integral unvented cylinder containing "secondary" water.
The effect is precisely the same
>
>> The 55 litre integral cylinder is depleted
>> when a tap is turned on and the burner
>> lights to supplement and recharge it.
>
>The burner replenished the spent hot water. In a heat bank the energy from
>the stored hot water "AND" the burner can be put to use "combined".
All that is happening is that energy is being taken from a store,
which because of the temperature has more energy stored than a
conventional cylinder - 25% more.
Energy can be added to this from the burner in either case and the
ultimate result is the same - hot water is available for longer than
if just the stored energy is depleted. That period will be longer
for a store, simply because more energy was stored in the first place.
In either case, once the stored energy is depleted, the limitation
will be the input power.
>Once
>again you talk of what you know little, or nothing, of.
It's simple physics and engineering - there's very little *to* know.
>
>> In essence, this is the same
>> as a boiler connected to a heatbank
>
>Not at all. see above.
Ultimately, it's just energy stored in a thermal mass.
>
>> >You should read more about heat banks
>> >instead of reading O levels physics
>> >books.
>>
>> This is first form.
>
>Heat banks in O levels school books? you are jesting of course.
>
>
Who said anything about O levels?
A heat bank works purely and simply on the principle of
energy in or out = mass x specific heat x temperature rise
A condensing boiler works mainly on the principle of the energy
released or absorbed, (latent heat) when a substance changes phase -
in this case from the gaseous to the liquid phase.
Liquids expanding with increasing temperature is also relevant.
I learned about all topics in first form grammar school.
All of the operational principles of heatbanks follow from this very
simple physics. There is nothing else to it. No magic.
Did you actually have a formal education?
abuse-imm@easy.com IMM
> >> >A condenser mated to UFH can be
> >> >highly efficient as the system runs of low
> >> >temps. To get the same high efficiency
> >> >with rads you require very large
> >> >rads which adds even more expense.
> >>
> >> They do not need to be very large
> >
> >They do and take up more space as well.
> >A no-flame boiler is better.
>
> I was easily able to handle this by swapping
> radiators without fins to
> those with, or doubles where there were singles.
A no-flame can run at 80C and still have high efficiencies, and smaller rads
too. A win, win.
> >Yet it shows the versitility and efficiency of a heat bank.
>
> Versatility, possibly, but only if you need that.
> Efficiency would
> depend on how it's used.
They are inherently efficient, and greatly misunderstood.
> >> If you go for a small store to save space,
> >> it stores relatively little energy.
> >
> >Not so.
>
> So where does it store it?
In the water.
> >Once again, you size to suit. You put in a 80 litre cylinder in a
> >conventional house with 2 baths you will run out of hot water - simple.
You
> >size the store to suite demand (this simple thing is something you can't
> >figure out as you have repeatedly said this) and they still will be
smaller
> >than unvented cylinders, as you are using all the energy available to
you.
> >the stored hot water and the power of the boiler. The best way to go.
>
> I haven't denied that a heatbank can be smaller than a conventional
> cylinder - to be precise 80% of the size if you run it at 75 degrees.
Less if at 80C. Have a no-flame boiler on it and high efficiencies all
around, as long as the insulation is very thick. A heat bank can be any
shape. So a square one can fit inside a under worktop cupboard.
> The energy from the boiler can be
> added whether it's a store or a
> cylinder.
Not so. There is a big difference between "replenishing" and "combining"
energy. A heat bank can do bath, merely by flicking a switch.
> I don't believe that for most people,
> having a 160 litre cylinder vs a
> 200 litre one in their airing cupboard
> makes a big difference,
Having an 80 Litre will. Also having a square heat bank will liberate most
of the cupboard.
> Having mains derived hot water
> in reasonable volumes, possibly not
> needing overflows and being able to
> DIY would appear to be rather more
> attractive.
Sounds like a heat bank.
> The notion that a small heatbank that
> fits under a worktop, even if it
> were desirable, can provide enough
> HW for the average house is
> misleading at best.
Nonsense. A square heat bank has more volume. A larger boiler more power.
Combine the outputs of the two and great flow.
> There are no wondrous gains to be had - just
> simple proportions between temperatures.
There wondrous gains to had if having a square heat bank and a powerful
boiler.
> >> The Baxi Maxflow is an example of
> >> such a product.
> >
> >Not so. It has an integral unvented cylinder
> >containing "secondary" water.
>
> The effect is precisely the same
It is NOT!!!
> >> The 55 litre integral cylinder is depleted
> >> when a tap is turned on and the burner
> >> lights to supplement and recharge it.
> >
> >The burner replenished the spent hot water.
> >In a heat bank the energy from
> >the stored hot water "AND" the burner
> >can be put to use "combined".
>
> All that is happening is that energy
> is being taken from a store,
In a Maxflow only hot water is being taken from the store, NOT ENERGY. A
heat bank stores hot water as energy as it is used to do something, which is
heat up cold water instantly.
> It's simple physics and engineering -
> there's very little *to* know.
Drop the O level books and undertsand heat banks.
> I learned about all topics in first form grammar school.
> Did you actually have a formal education?
Don't be silly!
Andy Hall
wrote:
>
>A no-flame can run at 80C and still have high efficiencies, and smaller rads
>too. A win, win.
Possibly, but this was not the topic of the thread.
>
>> >Yet it shows the versitility and efficiency of a heat bank.
>>
>> Versatility, possibly, but only if you need that.
>> Efficiency would
>> depend on how it's used.
>
>They are inherently efficient, and greatly misunderstood.
There is nothing *inherently* efficient about a tank of water.
That has to do with how it is used.
>
>> >> If you go for a small store to save space,
>> >> it stores relatively little energy.
>> >
>> >Not so.
>>
>> So where does it store it?
>
>In the water.
Precisely - so thje amount of storage is proportional to the size.
>
>> I haven't denied that a heatbank can be smaller than a conventional
>> cylinder - to be precise 80% of the size if you run it at 75 degrees.
>
>Less if at 80C. Have a no-flame boiler on it and high efficiencies all
>around, as long as the insulation is very thick. A heat bank can be any
>shape. So a square one can fit inside a under worktop cupboard.
Once again you are attempting to move the goal posts. The thread
mentioned condensing boilers. There appears to be only one
manufacturer using no-flame technology in domestic boilers at present
- an Italian company called NST - so this is a long way from being
widely used mainstream technology. While the UK Is retiscent about new
things, at least condensing technology has been used for more than 15
years in Germany and Holland.
As far as square heatbanks are concerned you appear to be having a
laugh or more likely making up ideas as you go along.
The volume of a rectangular solid is given by the area of the base
multiplied by the height. For example, a cube of one metre side has
a volume of one cubic metre.
The volume of a cylinder is given by the area of the base multiplied
by the height. The area is given by pi multiplied by the square of
the radius.
Thus a cylinder to fit inside a one metre cube will have a radius of
0.5m. The area of the base will be 0.785 square metres and the
volume 0.785 cubic metres. There is only 11% difference between the
two, which is hardly significant. Also, if you entirely fill the
space under the worktop with a rectangular solid, where are the other
pieces like the heat exchanger, pumps and valves going to go? At
least with a cylinder they can fit into the empty spaces.
You need to come up with a better one than that :-)
>
>> The energy from the boiler can be
>> added whether it's a store or a
>> cylinder.
>
>Not so. There is a big difference between "replenishing" and "combining"
>energy. A heat bank can do bath, merely by flicking a switch.
This is waffle. Heat is heat is heat. Energy out = energy stored +
energy in. The only difference is that a heatbank has the potential
to store more in a given space.
>
>> I don't believe that for most people,
>> having a 160 litre cylinder vs a
>> 200 litre one in their airing cupboard
>> makes a big difference,
>
>Having an 80 Litre will. Also having a square heat bank will liberate most
>of the cupboard.
An 80 litre store will hold the energy equivalent of a 100 litre
conventional cylinder - this is marginally adequate for a small house.
>
>> The notion that a small heatbank that
>> fits under a worktop, even if it
>> were desirable, can provide enough
>> HW for the average house is
>> misleading at best.
>
>Nonsense. A square heat bank has more volume.
11% - not significant.
> A larger boiler more power.
>Combine the outputs of the two and great flow.
You can always add more boiler capacity. A small heatbank is a small
heatbank, a small cylinder is a small cylinder. Each can only store
energy proportional to their size and temperature. If you have a
small storage capacity of either type, the "great flow" will run out
very quickly and you are left with what the boiler can do.
Taken to its logical conclusion, you might just as well do away with
it and use a combi because that is effectively what has been created -
energy out = energy in with no energy stored.
>
>> There are no wondrous gains to be had - just
>> simple proportions between temperatures.
>
>There wondrous gains to had if having a square heat bank and a powerful
>boiler.
If you want to believe that fine, but it doesn't have any basis in
reality.
>
>> >> The Baxi Maxflow is an example of
>> >> such a product.
>> >
>> >Not so. It has an integral unvented cylinder
>> >containing "secondary" water.
>>
>> The effect is precisely the same
>
>It is NOT!!!
Energy is the same. All that is different is that here it is a 60
degree store, whereas a CPSU is a 75 or 80 degree store.
In terms of what the user gets in practice the only difference is a
20% longer running time at a given flow rate and heat input.
>
>
>In a Maxflow only hot water is being taken from the store, NOT ENERGY. A
>heat bank stores hot water as energy as it is used to do something, which is
>heat up cold water instantly.
I have news for you. Energy stored in secondary hot water is no
different from energy stored in a primary or intermediate store.
In the case of the store, the stored energy in the primary or
intermediate hot water is used to heat the secondary water instantly.
In the case of secondary water stored, it is used directly.
The only difference is that with the heatbank, assuming 100%
efficiency of transfer of heat, you will get 20% more secondary hot
water for the same size of appliance. It is still energy and that is
the only difference.
>
>> It's simple physics and engineering -
>> there's very little *to* know.
>
>Drop the O level books and undertsand heat banks.
There's nothing to understand. As far as the square shaped ones are
concerned, we are talking about primary school mathematics.
>
>> I learned about all topics in first form grammar school.
>
>> Did you actually have a formal education?
>
>Don't be silly!
>
>
Considering that you can't see that the only principle here is storage
of energy in a volume of water at different temperatures and that you
think that there is a significant difference in volume between a
rectangular solid and a cylinder, I really begin to wonder.
abuse-imm@easy.com IMM
> >A no-flame can run at 80C and still have
> >high efficiencies, and smaller rads
> >too. A win, win.
>
> Possibly, but this was not the topic of the thread.
It is. the OP is requesting info on what to do. He now has lots of it.
> >They are inherently efficient, and greatly misunderstood.
>
> There is nothing *inherently* efficient
> about a tank of water.
> That has to do with how it is used.
And that is where a heat bank comes in.
> >> I haven't denied that a heatbank can be smaller than a conventional
> >> cylinder - to be precise 80% of the size if you run it at 75 degrees.
> >
> >Less if at 80C. Have a no-flame boiler on it and high efficiencies all
> >around, as long as the insulation is very thick. A heat bank can be any
> >shape. So a square one can fit inside a under worktop cupboard.
>
> Once again you are attempting to move the goal posts.
The OP wanted to know what is the best solution. That is simple and clear.
> The thread mentioned condensing boilers.
> There appears to be only one
> manufacturer using no-flame technology
> in domestic boilers at present
> - an Italian company called NST - so this
> is a long way from being widely used
> mainstream technology.
It is not in commercial circles. New government regs will mean only high
efficient boilers, which will exclude all current non-condensing boilers.
The no-flame will then come into its own as it does not give a nuisance
plume. The importers are targeting flats in cities, where a plume could be
a total nuisance. Other makers are looking at no-flame technology.
> While the UK Is retiscent about new
> things, at least condensing technology
> has been used for more than 15
> years in Germany and Holland.
We are in for a shock.
> As far as square heatbanks are
> concerned you appear to be having a
> laugh or more likely making up ideas
> as you go along.
A heat bank, which is pumped using a plate heat exchanger, can be any shape,
unlike a coiled thermal store. The store at the bottom of the Worcester
HighFlow is a strange shape, and nothing like cylindrical. Look at the DPS
site, I think they have a piccie of a square heat bank. They will make one
to order.
> The volume of a rectangular solid
> is given by the area of the base
> multiplied by the height.
10/10.
> For example, a cube of one metre side has
> a volume of one cubic metre.
Which is 1000 litres. A lot of storage for a such a small space taken.
Drop it by 1/8 in height to give 125 litres, put the plate and pump on top,
put it in an airing cupboard and a shelf above that, and all the cupboard is
used above. A lot of storge for such a small footprint.
> The volume of a cylinder is given by
> the area of the base multiplied
> by the height. The area is given by
> pi multiplied by the square of
> the radius.
10/10
> You need to come up with a better one than that :-)
See above. Sorted.
> >> The energy from the boiler can be
> >> added whether it's a store or a
> >> cylinder.
> >
> >Not so. There is a big difference
> >between "replenishing" and "combining"
> >energy. A heat bank can do both, merely
> >by flicking a switch.
>
> This is waffle. Heat is heat is heat. Energy out = energy stored +
> energy in. The only difference is that a heatbank has the potential
> to store more in a given space.
No the hot water inside a heat bank is energy that is to be used for another
purpose. You have been told that. In a cylinder secondary hot water is,
well just hot water for washing, the end product.
> >> I don't believe that for most people,
> >> having a 160 litre cylinder vs a
> >> 200 litre one in their airing cupboard
> >> makes a big difference,
> >
> >Having an 80 Litre will. Also having a
> >square heat bank will liberate most
> >of the cupboard.
>
> An 80 litre store will hold the energy
> equivalent of a 100 litre
> conventional cylinder - this is marginally
> adequate for a small house.
"combine" the output of the boiler and the stored energy and it sings. Why
waste that energy potential in a boiler. If it is there USE IT.
> >> The notion that a small heatbank that
> >> fits under a worktop, even if it
> >> were desirable, can provide enough
> >> HW for the average house is
> >> misleading at best.
> >
> >Nonsense. A square heat bank has more volume.
>
> 11% - not significant.
See above and O level maths books.
> > A larger boiler more power.
> >Combine the outputs of the
> >two and great flow.
>
> You can always add more boiler capacity.
> A small heatbank is a small
> heatbank, a small cylinder is a small cylinder.
Yet when a heat bank combines the two it sings.
> Taken to its logical conclusion,
> you might just as well do away with
> it and use a combi because that is
> effectively what has been created -
> energy out = energy in with no energy stored.
No combi has the flow rate of a "combined" boiler heat store heat bank. A
large boiler, which takes up no more space than a small one, can be mated to
the heat bank and even greater performance.
> >There wondrous gains to had if having
> >a square heat bank and a powerful
> >boiler.
>
> If you want to believe that fine,
> but it doesn't have any basis in
> reality.
These are real. They have been made. I think DPS made a raft for a local
authority in their council house refurbs. DO NOT contradict me in field you
know nothing. If you want to know ask.
> >> >> The Baxi Maxflow is an example of
> >> >> such a product.
> >> >
> >> >Not so. It has an integral unvented cylinder
> >> >containing "secondary" water.
> >>
> >> The effect is precisely the same
> >
> >It is NOT!!!
>
> Energy is the same.
You are still confused.
> >In a Maxflow only hot water is being
> >taken from the store, NOT ENERGY. A
> >heat bank stores hot water as energy as
> >it is used to do something, which is
> >heat up cold water instantly.
>
> I have news for you. Energy stored
> in secondary hot water is no
> different from energy stored in a primary
> or intermediate store.
If it is for washing then it is not useful energy at all. It is the product
of an energy train.
> >> It's simple physics and engineering -
> >> there's very little *to* know.
>
> >Drop the O level books and undertsand heat banks.
>
> There's nothing to understand.
Well only someone who doesn't understand them would say that.
> Considering that you can't see
> that the only principle here is storage
> of energy in a volume of water at
> different temperatures and that you
> think that there is a significant
> difference in volume between a
> rectangular solid and a cylinder, I
> really begin to wonder.
It is how the energy is used and "combined" with other energy sources (a
boiler) that makes the difference. You stop looking at the O level books
and listen to a pro.
Andy Hall
wrote:
>"Andy Hall" <an...@hall.nospam> wrote in message
>news:l3uvav0i91dt1r71a...@4ax.com...
>
>> >A no-flame can run at 80C and still have
>> >high efficiencies, and smaller rads
>> >too. A win, win.
>>
>> Possibly, but this was not the topic of the thread.
>
>It is. the OP is requesting info on what to do. He now has lots of it.
That's for sure.
>
>
>The OP wanted to know what is the best solution. That is simple and clear.
But not based on most of the factors that you have introduced - rather
much simpler ones like logistics.
>
>> The thread mentioned condensing boilers.
>> There appears to be only one
>> manufacturer using no-flame technology
>> in domestic boilers at present
>> - an Italian company called NST - so this
>> is a long way from being widely used
>> mainstream technology.
>
>It is not in commercial circles. New government regs will mean only high
>efficient boilers, which will exclude all current non-condensing boilers.
>
>The no-flame will then come into its own as it does not give a nuisance
>plume. The importers are targeting flats in cities, where a plume could be
>a total nuisance. Other makers are looking at no-flame technology.
That's over-stated. Pluming is not a big issue and with small 50mm
flues is easily dealt with.
>
>> While the UK Is retiscent about new
>> things, at least condensing technology
>> has been used for more than 15
>> years in Germany and Holland.
>
>We are in for a shock.
Undoubtedly.
>
>> As far as square heatbanks are
>> concerned you appear to be having a
>> laugh or more likely making up ideas
>> as you go along.
>
>
>Which is 1000 litres. A lot of storage for a such a small space taken.
>Drop it by 1/8 in height to give 125 litres, put the plate and pump on top,
>put it in an airing cupboard and a shelf above that, and all the cupboard is
>used above. A lot of storge for such a small footprint.
There are not many airing cupboards that I've seen that will
accomodate a footprint of 1m^2. Even fewer kitchen spaces.
>
>> The volume of a cylinder is given by
>> the area of the base multiplied
>> by the height. The area is given by
>> pi multiplied by the square of
>> the radius.
>
>10/10
>
>> You need to come up with a better one than that :-)
>
>See above. Sorted.
In your dreams.
>
>> >> The energy from the boiler can be
>> >> added whether it's a store or a
>> >> cylinder.
>> >
>> >Not so. There is a big difference
>> >between "replenishing" and "combining"
>> >energy. A heat bank can do both, merely
>> >by flicking a switch.
>>
>> This is waffle. Heat is heat is heat. Energy out = energy stored +
>> energy in. The only difference is that a heatbank has the potential
>> to store more in a given space.
>
>No the hot water inside a heat bank is energy that is to be used for another
>purpose. You have been told that. In a cylinder secondary hot water is,
>well just hot water for washing, the end product.
Oh I see. So there's a difference between "primary" heat and
"secondary" heat. It's curious that both are measured using the
same units and have exactly the same characteristics. You'll be
telling us next that a different kind of water is needed for heat
stores because of this different kind of energy. Heavy water for
example. That's thicker and gloopier so it should work better.
Is there a special thermometer for measuring the temperature of heat
store water? I assume there must be since it's so special and can do
things that ordinary water can't, even varying its physical behaviour
to suit the discussion at hand. Do you have to add mojo as well?
>
>>
>> An 80 litre store will hold the energy
>> equivalent of a 100 litre
>> conventional cylinder - this is marginally
>> adequate for a small house.
>
>"combine" the output of the boiler and the stored energy and it sings. Why
>waste that energy potential in a boiler. If it is there USE IT.
>
Absolutely, but let's not kid ourselves or be kidded by your good self
that anything fundamentally clever is happening that is different
between storing water at 60 degrees or at 75. Only the amounts and
timings change.
>> >> The notion that a small heatbank that
>> >> fits under a worktop, even if it
>> >> were desirable, can provide enough
>> >> HW for the average house is
>> >> misleading at best.
>> >
>> >Nonsense. A square heat bank has more volume.
>>
>> 11% - not significant.
>
>See above and O level maths books.
11+ you mean.
>
>> > A larger boiler more power.
>> >Combine the outputs of the
>> >two and great flow.
>>
>> You can always add more boiler capacity.
>> A small heatbank is a small
>> heatbank, a small cylinder is a small cylinder.
>
>Yet when a heat bank combines the two it sings.
In the same way as adding boiler input to a conventional cylinder will
as water from it is used. In terms of what comes out there is no
difference.
>
>> Taken to its logical conclusion,
>> you might just as well do away with
>> it and use a combi because that is
>> effectively what has been created -
>> energy out = energy in with no energy stored.
>
>No combi has the flow rate of a "combined" boiler heat store heat bank.
More gobbledygook
>A
>large boiler, which takes up no more space than a small one, can be mated to
>the heat bank and even greater performance.
All you have said here can be described by
Energy out = energy stored + energy in
This is what happens when you increase energy in. Guess what - energy
out increases. When energy out increases you can have more HW for
longer. Energy stored defines how long energy out lasts before it
drops to the energy in level.
Ever thought of applying to NASA?
>
>> >There wondrous gains to had if having
>> >a square heat bank and a powerful
>> >boiler.
>>
>> If you want to believe that fine,
>> but it doesn't have any basis in
>> reality.
>
>These are real. They have been made.
Quite possibly but it is not really of any importance.
No doubt they have been made in all sorts of shapes and sizes, but
still the energy stored is defined by the volume.
> I think DPS made a raft for a local
>authority in their council house refurbs.
Sinking were they?
>DO NOT contradict me in field you
>know nothing. If you want to know ask.
There's nothing to contradict. You persist in pulling all sorts of
irrelevant nonsense out of thin air, that you are unable to
substantiate, and which in fact can't be substantiated because to do
so would defy basic laws of physics. When challenged, you change
the content of the discussion in an attempt to add further mystery and
appearance of sophisticated knowledge on what is fundamentally a
trivial technology.
Why you would think that anyone would be taken in by that rather than
a simple explanation of what is happening I have no idea.
>
>> >In a Maxflow only hot water is being
>> >taken from the store, NOT ENERGY. A
>> >heat bank stores hot water as energy as
>> >it is used to do something, which is
>> >heat up cold water instantly.
>>
>> I have news for you. Energy stored
>> in secondary hot water is no
>> different from energy stored in a primary
>> or intermediate store.
>
>If it is for washing then it is not useful energy at all.
You like washing in cold?
> It is the product
>of an energy train.
The 4.52 to Penzance?
>
>> >> It's simple physics and engineering -
>> >> there's very little *to* know.
>>
>> >Drop the O level books and undertsand heat banks.
>>
>> There's nothing to understand.
>
>Well only someone who doesn't understand them would say that.
The special energy inside or the mystical powers?
>
>> Considering that you can't see
>> that the only principle here is storage
>> of energy in a volume of water at
>> different temperatures and that you
>> think that there is a significant
>> difference in volume between a
>> rectangular solid and a cylinder, I
>> really begin to wonder.
>
>It is how the energy is used and "combined" with other energy sources (a
>boiler) that makes the difference.
The only difference is that with a store, the stored water is at a
higher temperature than a normal cylinder. Because of this, more
energy can be stored in a given space. The energy can also be
transferred through a heat exchanger to secondary water that will be
used directly. With an efficient plate heat exchanger, I can transfer
that energy from one to the other rapidly and achieve almost as high a
flow rate as using the water directly - certainly an adequate one.
If I add energy back into the store from a boiler, I can go on taking
it out for longer to heat the secondary water than if I don't.
With a cylinder I simply use the water directly and require about a
20% larger cylinder. I can also add energy back from a boiler and
combine with what's stored in the secondary water to give output for a
longer time.
That's it.
>You stop looking at the O level books
>and listen to a pro.
>
>
Did you ever do O levels? What exactly is your HVAC qualification?
IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> >The OP wanted to know what
> >is the best solution. That is simple and clear.
>
> But not based on most of the factors
> that you have introduced
Because you never knew them.
> >The no-flame boiler will then come into
> >its own as it does not give a nuisance
> >plume. The importers are targeting
> >flats in cities, where a plume could be
> >a total nuisance. Other makers are
> >looking at no-flame technology.
>
> That's over-stated. Pluming is not a big
> issue
IT IS! In flats in towns and cities.
> >> As far as square heatbanks are
> >> concerned you appear to be having a
> >> laugh or more likely making up ideas
> >> as you go along.
> >
> >Which is 1000 litres. A lot of storage for a such a small space taken.
> >Drop it by 1/8 in height to give 125 litres, put the plate and pump on
top,
> >put it in an airing cupboard and a shelf above that, and all the cupboard
is
> >used above. A lot of storge for such a small footprint.
>
> There are not many airing cupboards that I've seen that will
> accomodate a footprint of 1m^2. Even fewer kitchen spaces.
Read the O level maths book again. You can make it 0.75 x 0.75 and raise the
height. Duh!!
> >No the hot water inside a heat bank is energy that is to be used for
another
> >purpose. You have been told that. In a cylinder secondary hot water is,
> >well just hot water for washing, the end product.
>
> Oh I see. So there's a difference
> between "primary" heat and
> "secondary" heat.
Yes!! One is the end result, the product of the energy train, the other is
energy to be used.
> >"combine" the output of the boiler
> >and the stored energy and it sings. Why
> >waste that energy potential in a boiler.
> >If it is there USE IT.
>
> Absolutely,
Is the penny dropping?
> but let's not kid ourselves
> or be kidded by your good self
> that anything fundamentally clever
> is happening that is different
> between storing water at 60 degrees
> or at 75. Only the amounts and
> timings change.
I don't change physics. A heat bank uses energy in an efficient manner.
> >> > A larger boiler more power.
> >> >Combine the outputs of the
> >> >two and great flow.
> >>
> >> You can always add more boiler capacity.
> >> A small heatbank is a small
> >> heatbank, a small cylinder is a small cylinder.
> >
> >Yet when a heat bank combines the two it sings.
>
> In the same way as adding
> boiler input to a conventional cylinder
NONSENSE!!!!
> >> Taken to its logical conclusion,
> >> you might just as well do away with
> >> it and use a combi because that is
> >> effectively what has been created -
> >> energy out = energy in with no energy stored.
> >
> >No combi has the flow rate of a "combined" boiler heat store heat bank.
>
> More gobbledygook
That is clear. I will put an and in for you.
No combi has the flow rate of a "combined" boiler and heat store heat bank.
> >A large boiler, which takes up no
> >more space than a small one, can be mated to
> >the heat bank and even greater performance.
>
> All you have said here can be described by
>
> Energy out = energy stored + energy in
>
> This is what happens when you increase
> energy in.
I will repeat. If I say it often enough it may sink in. A heat bank is the
"ONLY" setup on the market that can "combine" the outputs of a boiler and
the heat store of a heat bank to give very high flow rates. The larger the
system boiler used the less in size the store needs be. As larger output
wall mounted boilers are not much bigger or expensive than the smaller
versions, it makes sense to use as large a boiler as possible in size and
economics.
It can also be switched to a replenishement mode in which the boiler only
cuts in when the store is near depleted to give a long efficient no boiler
cycle burn. DO YOU UNDERSTAND?
> Ever thought of applying to NASA?
They keep trying to poach me.
> >> >There wondrous gains to had if having
> >> >a square heat bank and a powerful
> >> >boiler.
> >>
> >> If you want to believe that fine,
> >> but it doesn't have any basis in
> >> reality.
> >
> >These are real. They have been made.
>
> Quite possibly
Actually!!!!
> but it is not really of any importance.
Very were very important to those who used them.
> No doubt they have been made
> in all sorts of shapes and sizes, but
> still the energy stored is defined by the volume.
Go away???? You don't say????
> >DO NOT contradict me in field you
> >know nothing. If you want to know ask.
>
> There's nothing to contradict.
You have done nothing else, and implied lies.
> You persist in pulling all sorts of
> irrelevant nonsense out of thin air,
> that you are unable to
> substantiate,
You can't understand something fundamentally simple.
> >> >In a Maxflow only hot water is being
> >> >taken from the store, NOT ENERGY. A
> >> >heat bank stores hot water as energy as
> >> >it is used to do something, which is
> >> >heat up cold water instantly.
> >>
> >> I have news for you. Energy stored
> >> in secondary hot water is no
> >> different from energy stored in a primary
> >> or intermediate store.
> >
> >If it is for washing then it is not useful energy at all.
>
> You like washing in cold?
Hot water for washing is an end product
> The special energy inside or the mystical powers?
You are a fool!!! You think you fully researched a market you know nothing
of to update your boiler/heating system. You never did and failed, as a
better and cheaper solution is available. You are foolishly attempting to
justify a flawed decision.
Christian McArdle
>is the "ONLY" setup on the market that can "combine" the outputs of
>a boiler and the heat store of a heat bank to give very high flow
>rates.
A rapid recovery mains hot water cylinder also does this. Unless, of course,
you take the term "heat store of a heat bank" literally. That would be like
saying the only way to get to Edinburgh quickly by train is to take the
train! Correct, but a useless statement.
However, with a simple modification of your sentence, a rapid recovery mains
hot water cylinder (or, alternatively, a heat bank) is a setup on the market
that can "combine" the outputs of a boiler and the energy stored in an
insulated hot water storage vessel to give very high flow rates.
The mains pressure hot water cylinder can also do so using lower temperature
storage suited to the efficient use of commonly available condensing boiler
technology. The heat bank requires a higher temperature suited to older
non-condensing boiler technology and the promising future no-flame
technology boilers, that may allow a reduced footprint in the storage vessel
and the use of anti-corrosive chemicals in the vessel itself.
Is that settled then? ;-)
Christian.
IMM
"Christian McArdle" <cmcar...@nospam.yahooxxxx.co.uk> wrote in message
news:3eb1282a$0$4862$ed9e...@reading.news.pipex.net...
> >I will repeat. If I say it often enough it
> >may sink in. A heat bank is the "ONLY"
> >setup on the market that can "combine"
> >the outputs of a boiler and the heat store
> >of a heat bank to give very high flow
> >rates.
>
> A rapid recovery mains hot water
> cylinder also does this.
It does NOT, it replenishes hot water not "combine". Read above again.
> Is that settled then? ;-)
Read the thread. It is not a debate, it is me eduacting a man. What I say
is how it is.
Christian McArdle
The means of maintaining the output is immaterial and of no concern to the
user. The effect at the taps will be the same. If the draw of hot water is
less than the maximum boiler power (assuming correctly sized coil), the hot
water will not run out. This is the same whether it is a combi, heat bank or
hot water cylinder.
However, if by "replenishment" you mean that the boiler will only fire after
the water is no longer being drawn and can play no part in maintaining hot
water supply continuously, you are wrong.
Christian.
Andy Hall
<cmcar...@nospam.yahooxxxx.co.uk> wrote:
>>I will repeat. If I say it often enough it may sink in. A heat bank
>>is the "ONLY" setup on the market that can "combine" the outputs of
>>a boiler and the heat store of a heat bank to give very high flow
>>rates.
>
>A rapid recovery mains hot water cylinder also does this. Unless, of course,
>you take the term "heat store of a heat bank" literally. That would be like
>saying the only way to get to Edinburgh quickly by train is to take the
>train! Correct, but a useless statement.
Quite.
>
>However, with a simple modification of your sentence, a rapid recovery mains
>hot water cylinder (or, alternatively, a heat bank) is a setup on the market
>that can "combine" the outputs of a boiler and the energy stored in an
>insulated hot water storage vessel to give very high flow rates.
Exactly.
>
>The mains pressure hot water cylinder can also do so using lower temperature
>storage suited to the efficient use of commonly available condensing boiler
>technology. The heat bank requires a higher temperature suited to older
>non-condensing boiler technology and the promising future no-flame
>technology boilers, that may allow a reduced footprint in the storage vessel
>and the use of anti-corrosive chemicals in the vessel itself.
Yes.
>
>Is that settled then? ;-)
That's basically all that I have been pointing out, apart from to say
that there may be other decision criteria such as routing of discharge
pipes (or not being able to), that would influence what to use. In the
case of the OP, this and the likely need for a pressurised indirect
primary probably makes the decision.
>
>Christian.
Andy Hall
>
>"Andy Hall" <an...@hall.nospam> wrote in message
>news:onc0bvomspd4okole...@4ax.com...
>
>> >The OP wanted to know what
>> >is the best solution. That is simple and clear.
>>
>> But not based on most of the factors
>> that you have introduced
>
>Because you never knew them.
No, because only a few very specific ones were important.
>
>>
>> That's over-stated. Pluming is not a big
>> issue
>
>IT IS! In flats in towns and cities.
It's very simple to flue the boiler upwards or through the roof.
This is how it is done, very effectively in Germany.
Even on horizontal flues it's very easy to add a 45 degree terminal
and direct the output up and away from the building. If pluming is
then of nuisance value it is likely that the terminal is not installed
in a location deemed as appropriate by the gas safety legislation
anyway.
>
>> >No the hot water inside a heat bank is energy that is to be used for
>another
>> >purpose. You have been told that. In a cylinder secondary hot water is,
>> >well just hot water for washing, the end product.
>>
>> Oh I see. So there's a difference
>> between "primary" heat and
>> "secondary" heat.
>
>Yes!! One is the end result, the product of the energy train, the other is
>energy to be used.
From the perspective of what comes out as the end product to fill the
bath, it makes no difference. All that is achieved at best is a
slightly smaller storage appliance.
>
>> but let's not kid ourselves
>> or be kidded by your good self
>> that anything fundamentally clever
>> is happening that is different
>> between storing water at 60 degrees
>> or at 75. Only the amounts and
>> timings change.
>
>I don't change physics. A heat bank uses energy in an efficient manner.
This is more waffle. The only place where efficiency could be
increased is if the heat store is matched to a boiler with peak or
equal efficiency at the storage temperature. This certainly isn't
the case with condensing technology. It might be with a no-flame
boiler, assuming the manufacturer's data of 95-96% gross efficiency is
correct across the temperature range. This all ignores
inefficiencies in the plate heat exchanger and the elevated storage
temperature.
>
>> >> > A larger boiler more power.
>> >> >Combine the outputs of the
>> >> >two and great flow.
>> >>
>> >> You can always add more boiler capacity.
>> >> A small heatbank is a small
>> >> heatbank, a small cylinder is a small cylinder.
>> >
>> >Yet when a heat bank combines the two it sings.
>>
>> In the same way as adding
>> boiler input to a conventional cylinder
>
>NONSENSE!!!!
Sorry, but it isn't. In terms of the end result, energy is combined.
The only difference is thatin one case it is energy relating to
storage at 75 to 80 degrees vs. 60.
>
>> >> Taken to its logical conclusion,
>> >> you might just as well do away with
>> >> it and use a combi because that is
>> >> effectively what has been created -
>> >> energy out = energy in with no energy stored.
>> >
>> >No combi has the flow rate of a "combined" boiler heat store heat bank.
>>
>> More gobbledygook
>
>That is clear. I will put an and in for you.
>No combi has the flow rate of a "combined" boiler and heat store heat bank.
That much is obvious, which means that to achieve a worthwhile effect
from combining, a store large enough for the required running time
with boiler energy added is needed. Exactly the same as for a
conventional cylinder.
>
>> >A large boiler, which takes up no
>> >more space than a small one, can be mated to
>> >the heat bank and even greater performance.
>>
>> All you have said here can be described by
>>
>> Energy out = energy stored + energy in
>>
>> This is what happens when you increase
>> energy in.
>
>I will repeat. If I say it often enough it may sink in. A heat bank is the
>"ONLY" setup on the market that can "combine" the outputs of a boiler and
>the heat store of a heat bank to give very high flow rates.
Obviously a heat bank is the only set up that combine the output of a
boiler and the heat store of a heat bank - that's an obvious
statement.
However, a conventional cylinder can combine boiler energy output with
that already stored in the secondary water and provide the same effect
which is to increase the flow rate and/or running time before the
stored energy is depleted.
>The larger the
>system boiler used the less in size the store needs be. As larger output
>wall mounted boilers are not much bigger or expensive than the smaller
>versions, it makes sense to use as large a boiler as possible in size and
>economics.
This is the instant hot water argument. You already said, quite
rightly that no combi can match the combined output of a store and a
boiler. As you make the store smaller, you have less stored energy
to play with and have to rely on the boiler. The fact that a combi
doesn't come near, and if you do require substantial output, it
follows that the store can't be made that small. If the requirements
are more modest then a store might not be needed and a combi adequate.
>
>It can also be switched to a replenishement mode in which the boiler only
>cuts in when the store is near depleted to give a long efficient no boiler
>cycle burn. DO YOU UNDERSTAND?
Perfectly. The downside of that mode is that there will then be
little energy left in the store and not much left to combine. Also,
to run successive baths or showers it means that the system overall is
effectively working like a combi with an indirect circuit in the
middle.
I did actually do a test like this and compared how much gas was used
if I let the boiler fire up soon after starting to draw water vs.
preventing it until I had almost used up the cylinder contents.
There was very little difference - I suspect because the burner
modulates when the cylinder is almost replenished.
>
>> Ever thought of applying to NASA?
>
>They keep trying to poach me.
I'll put in a word for you....
>
>> >DO NOT contradict me in field you
>> >know nothing. If you want to know ask.
>>
>> There's nothing to contradict.
>
>You have done nothing else, and implied lies.
I've implied nothing of the sort - only to bring a lengthy list of
irrelevancies back to fundamental principles of physics which then
make obvious what is going to achieved and what is not.
>
>
>Hot water for washing is an end product
which is what the system is being installed to produce.
>
>
>You are a fool!!! You think you fully researched a market you know nothing
>of to update your boiler/heating system.
That I did, taking into account the criteria for selection that I had.
I know that you would like to make the whole thing far more
complicated than it actually is, but the fact is that none of this is
sophisticated technology and it is very easy to see past the claims of
manufacturers to identify what really is going to happen.
Since you have never been able to substantiate any claims to
professional expertise in the HVAC field, you are not really in a
position to comment.
> You never did and failed, as a
>better and cheaper solution is available.
I still have the notes and calculations that I made. For my criteria
(which incidentally I have not introduced here), there was no
advantage in the use of a thermal store vs. a conventional fast
recovery cylinder from an operational or from a cost perspective.
>You are foolishly attempting to
>justify a flawed decision.
>
For my criteria, the decisions were correct and the results entirely
as predicted.
IMM
> If the draw of hot water is
> less than the maximum boiler
> power (assuming correctly sized coil),
> the hot water will not run out. This
> is the same whether it is a combi, heat bank or
> hot water cylinder.
>
> However, if by "replenishment"
NO. 1, unvented cylinders do not have particularly high efficiency coils, so
boiler size is limited. With a heat bank any sized boiler can be fitted if
it is direct. You can have a 200,000 btus boiler on a 80 litre heat bank if
you want. The output of the boiler goes directly to heat the incoming mains
cold water, it does not in an unvented cylinder. In a heat bank it can be
combined with the stored waters energy, which it cannot with an unvented
cylinder. In an unvented cylinder if the cylinder runs cold and the flow is
reduced to match the input of the boiler you will never get hot water as it
will be attempting to heat the mass of water which is being cooled by
incoming water. You will have to wait for replenishment and then attempt to
match the flow with the boilers load. With a heat bank if the store runs
cold the output will what the boiler delivers (approx 10-11 litres/min with
a 90-100,000 btus boiler). You will always have hot water. With a heat
bank if the flow is less than what the boiler delivers then it adds the heat
to the mass of stored water. Also with a heat bank you can switch the mode
from "combined" to replenishment to give a long efficient no boiler cycle
burn. So in normal use you replenish and when there is high demand, when
say visitors are in use "combined". A win, win, win. Got it? I don't
think you have.
IMM
"Andy Hall" <an...@hall.nospam> wrote in message
Amazing! The blind leading the blind.
IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> >> That's over-stated. Pluming is not a big
> >> issue
> >
> >IT IS! In flats in towns and cities.
>
> It's very simple to flue the boiler
> upwards or through the roof.
> This is how it is done,
Have you ever been in flats? especially the old converted Victorian ones?
< snip uninformed drivel >
Andy Hall
>
>"Christian McArdle" <cmcar...@nospam.yahooxxxx.co.uk> wrote in message
>news:3eb1436e$0$4863$ed9e...@reading.news.pipex.net...
>
>> If the draw of hot water is
>> less than the maximum boiler
>> power (assuming correctly sized coil),
>> the hot water will not run out. This
>> is the same whether it is a combi, heat bank or
>> hot water cylinder.
>>
>> However, if by "replenishment"
>
>NO. 1, unvented cylinders do not have particularly high efficiency coils, so
>boiler size is limited. With a heat bank any sized boiler can be fitted if
>it is direct.
That's a big *if*. The placement of the store, whether or not it can
be self contained and the design of the primary CH arrangements all
depend on it.
> You can have a 200,000 btus boiler on a 80 litre heat bank if
>you want.
A 58kW boiler heating 80 litres. A very well proportioned system.
>The output of the boiler goes directly to heat the incoming mains
>cold water, it does not in an unvented cylinder.
No it doesn't. It heats the water in the store which in turn heats
the cold mains water via a plate heat exchanger. I think you are
thinking of a combi here.
> In a heat bank it can be
>combined with the stored waters energy, which it cannot with an unvented
>cylinder.
As described already it obviously can.
> In an unvented cylinder if the cylinder runs cold and the flow is
>reduced to match the input of the boiler you will never get hot water as it
>will be attempting to heat the mass of water which is being cooled by
>incoming water. You will have to wait for replenishment and then attempt to
>match the flow with the boilers load. With a heat bank if the store runs
>cold the output will what the boiler delivers (approx 10-11 litres/min with
>a 90-100,000 btus boiler). You will always have hot water.
This is complete nonsense. First of all the cylinder should be sized
so that this doesn't happen. Secondly, in the case of the cylinder,
heat will be transferred to the water according to the capabilities of
the coil and the match of the boiler to that.
>With a heat
>bank if the flow is less than what the boiler delivers then it adds the heat
>to the mass of stored water.
The same as with a cylinder.
>Also with a heat bank you can switch the mode
>from "combined" to replenishment to give a long efficient no boiler cycle
>burn. So in normal use you replenish and when there is high demand, when
>say visitors are in use "combined".
The same can be achieved by positioning and switching the thermostat
on the cylinder. I can do it in software on my boiler. No
significant difference that I could measure.
>A win, win, win. Got it? I don't
>think you have.
>
>
That's because it isn't.
IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> >> If the draw of hot water is
> >> less than the maximum boiler
> >> power (assuming correctly sized coil),
> >> the hot water will not run out. This
> >> is the same whether it is a combi, heat bank or
> >> hot water cylinder.
> >>
> >> However, if by "replenishment"
> >
> >NO. 1, unvented cylinders do not
> >have particularly high efficiency coils, so
> >boiler size is limited. With a heat bank
> >any sized boiler can be fitted if
> >it is direct.
>
> That's a big *if*.
If "if" is the boiler and it is 200,000 Btus, then that "if" is big.
> > You can have a 200,000 btus boiler
> > on a 80 litre heat bank if you want.
>
> A 58kW boiler heating 80 litres.
> A very well proportioned system.
A very effective one too.
> >The output of the boiler goes
> >directly to heat the incoming mains
> >cold water, it does not in an unvented cylinder.
>
> No it doesn't.
It does. You have told!
> It heats the water in the store
> which in turn heats the cold mains
> water via a plate heat exchanger.
The water in the boiler goes straight to the plate heat exchanger across the
top of a flat topped store. It can also bypassthe store if the pipoewrok is
arranged so. DO YOU UNDERSTAND?
> > In an unvented cylinder if the cylinder runs cold and the flow is
> >reduced to match the input of the boiler you will never get hot water as
it
> >will be attempting to heat the mass of water which is being cooled by
> >incoming water. You will have to wait for replenishment and then attempt
to
> >match the flow with the boilers load. With a heat bank if the store runs
> >cold the output will what the boiler delivers (approx 10-11 litres/min
with
> >a 90-100,000 btus boiler). You will always have hot water.
>
> This is complete nonsense.
< snip more drivel by an ...well.... re-read al the thread 4 times >
Andy Hall
>
>> >
>> >NO. 1, unvented cylinders do not
>> >have particularly high efficiency coils, so
>> >boiler size is limited. With a heat bank
>> >any sized boiler can be fitted if
>> >it is direct.
>>
>> That's a big *if*.
>
>If "if" is the boiler and it is 200,000 Btus, then that "if" is big.
Too right.
>
>> > You can have a 200,000 btus boiler
>> > on a 80 litre heat bank if you want.
>>
>> A 58kW boiler heating 80 litres.
>> A very well proportioned system.
>
>A very effective one too.
Almost like a combi if you were to take the store away.
With a 58kW boiler, a small store like this is not going to contribute
a lot.
>
>> >The output of the boiler goes
>> >directly to heat the incoming mains
>> >cold water, it does not in an unvented cylinder.
>>
>
>> No it doesn't.
>
>It does. You have told!
In English please.
>
>> It heats the water in the store
>> which in turn heats the cold mains
>> water via a plate heat exchanger.
>
>The water in the boiler goes straight to the plate heat exchanger across the
>top of a flat topped store. It can also bypassthe store if the pipoewrok is
>arranged so. DO YOU UNDERSTAND?
There will be a mixing effect, because there is one pump circulating
between pump and store and another between store and heat exchanger.
I had also thought of the redirect the boiler water through the plate
exchanger idea. However, do you know of a product that implements
this in practice? It would in any case only work for a direct store
and in effect you have created a combi - not very interesting.
IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> >> >NO. 1, unvented cylinders do not
> >> >have particularly high efficiency coils, so
> >> >boiler size is limited. With a heat bank
> >> >any sized boiler can be fitted if
> >> >it is direct.
> >>
> >> That's a big *if*.
> >
> >If "if" is the boiler and it is 200,000
> >Btus, then that "if" is big.
>
> Too right.
And why not. If a boiler(s) is/are cost effective to buy then use one/them.
Two combi's can be had for £800 that deliver 200,000 Btus. Then you also
have back up if is down. Have then heat a heat bank and the performance is
staggering for little outlay and full backup.
> >> > You can have a 200,000 btus boiler
> >> > on a 80 litre heat bank if you want.
> >>
> >> A 58kW boiler heating 80 litres.
> >> A very well proportioned system.
> >
> >A very effective one too.
>
> Almost like a combi if you were
> to take the store away.
But the store is there giving all its benefits. It is using all the
available energy available. It is there so use it.
> With a 58kW boiler, a small store like
> this is not going to contribute a lot.
It will. It will provide a bath and more and the boiler supplying energy
ensuring the store will last a long time.
> >> It heats the water in the store
> >> which in turn heats the cold mains
> >> water via a plate heat exchanger.
> >
> >The water in the boiler goes straight
> >to the plate heat exchanger across the
> >top of a flat topped store. It can also
> >bypass the store if the pipoewrok is
> >arranged so. DO YOU UNDERSTAND?
>
> There will be a mixing effect, because
> there is one pump circulating
> between pump and store and another
> between store and heat exchanger.
But the boiler will deliver hot water at say 80C, so mixing will be minimal
as the store has a flat top and the flow pipe from the boiler is opposite
the flow pipe to the plate heat exchanger. The hot boiler supplied water
will go straight across the top and mixing will be so minimal it is not
worth talking about. You can also have the boiler feed the plate heat
exchanger direct and bypass the store. Did you read that bit in the last
post? If you did you didn't understand.
> I had also thought of the redirect
> the boiler water through the plate
> exchanger idea.
Please do not think. Just read and understand.
> However, do you know of a
> product that implements
> this in practice?
The DPS GVX. Can be sized up to what you want. The standard product is 80
litres as it is aimed at a one bathroom house. I believe it does CH & DHW.
They give test performance data using a 50-60,000 Btus boiler. Having
supply DHW only and the performance is even better. You can put a larger
boiler on and the performance is even better. A GVX and two combi's used a
system boilers would be less than you paid for your boiler. Also a 80 litre
GVX and Baxi 130,000 Btus condenser is still less than you paid for your
boiler as is a GVX and two Glow Worm 95,000 Btus condensing boilers. Two
boilers and back up too.
> It would in any case only work
> for a direct store and in effect
> you have created a combi - not
> very interesting.
Once again it is NOT A COMBI. A combi is all inside one casing, hence the
word "combi", meaning "combination" boiler, combining DHW and CH. Read the
above 10 times, it might sink in.
Andy Hall
>
>> >
>> >If "if" is the boiler and it is 200,000
>> >Btus, then that "if" is big.
>>
>> Too right.
>
>And why not. If a boiler(s) is/are cost effective to buy then use one/them.
>Two combi's can be had for £800 that deliver 200,000 Btus.
.... which won't run from a standard domestic supply.
> Then you also
>have back up if is down. Have then heat a heat bank and the performance is
>staggering for little outlay and full backup.
This doesn't make sense.
>>
>> Almost like a combi if you were
>> to take the store away.
>
>But the store is there giving all its benefits. It is using all the
>available energy available. It is there so use it.
With only 85 litres stored, the energy in comparison to the boiler is
small
>
>> With a 58kW boiler, a small store like
>> this is not going to contribute a lot.
>
>It will. It will provide a bath and more and the boiler supplying energy
>ensuring the store will last a long time.
85 litres of water dropping in temperature from 75 to 60 degrees will
release
85 x 4200 x 15 = 5,355,000 Joules
200kW of boiler produces 200,000 joules per second
It will have produced the same amount of energy in 26.775 seconds
as was stored in the store.
Like I said, a pointless exercise, and one that demonstrates that you
are just pulling ideas out of the air that have no sound foundation in
science or engineering.
>
>> >> It heats the water in the store
>> >> which in turn heats the cold mains
>> >> water via a plate heat exchanger.
>> >
>> >The water in the boiler goes straight
>> >to the plate heat exchanger across the
>> >top of a flat topped store. It can also
>> >bypass the store if the pipoewrok is
>> >arranged so. DO YOU UNDERSTAND?
>>
>> There will be a mixing effect, because
>> there is one pump circulating
>> between pump and store and another
>> between store and heat exchanger.
>
>But the boiler will deliver hot water at say 80C, so mixing will be minimal
>as the store has a flat top and the flow pipe from the boiler is opposite
>the flow pipe to the plate heat exchanger. The hot boiler supplied water
>will go straight across the top and mixing will be so minimal it is not
>worth talking about. You can also have the boiler feed the plate heat
>exchanger direct and bypass the store. Did you read that bit in the last
>post? If you did you didn't understand.
I understood it all perfectly and commented on it. There will be
mixing, but who is to say how much. For certain the heat transfer
rate will be reduced compared with a direct connection.
Having the boiler feed the heat exchanger just creates a combi which
is a big yawn.
>
>> I had also thought of the redirect
>> the boiler water through the plate
>> exchanger idea.
>
>Please do not think. Just read and understand.
That really is a scary suggestion.
>
>> However, do you know of a
>> product that implements
>> this in practice?
>
>The DPS GVX. Can be sized up to what you want. The standard product is 80
>litres as it is aimed at a one bathroom house. I believe it does CH & DHW.
Questionable with a condensing boiler for reasons already clearly
stated.
>They give test performance data using a 50-60,000 Btus boiler. Having
>supply DHW only and the performance is even better. You can put a larger
>boiler on and the performance is even better.
The "performance" isn't better. See explanation above.
>A GVX and two combi's used a
>system boilers would be less than you paid for your boiler. Also a 80 litre
>GVX and Baxi 130,000 Btus condenser is still less than you paid for your
>boiler as is a GVX and two Glow Worm 95,000 Btus condensing boilers. Two
>boilers and back up too.
That couldn't be run from a domestic gas supply and achieve virtually
nothing in performance. The store would be exhausted in a very short
time and the behaviour would be equivalent to a combi.
>
>> It would in any case only work
>> for a direct store and in effect
>> you have created a combi - not
>> very interesting.
>
>Once again it is NOT A COMBI. A combi is all inside one casing, hence the
>word "combi", meaning "combination" boiler, combining DHW and CH. Read the
>above 10 times, it might sink in.
>
I fully realise that it isn't a combi in the sense of being the 21st
century answer to the Ascot, but the system reduces down to burner
heats primary water in heat exchanger - energy in primary water
transferred instantly to secondary water in secondary plate heat
exchanger.
Put another way - energy out (almost) equals energy in + energy stored
where energy stored = 0.
i.e. what comes out = what is going in, and there is no storage once
the store is depleted moments after switching on the water.
Did you ever study specific heat at school? If you did, and had been
paying attention in class that day, all of this would be glaringly
obvious. It is only first form physics. Even latent heat, which you
need to be aware of to understand why a condensing boiler behaves as
it does is only two lessons further on.
We aren't even going as far as the principles of DuLong and Petit,
otherwise known as the long and the short of it which give us that
specific heat capacities of solids and liquids are constant over a
wide temperature range. That was the following week.
IMM
> >> >If "if" is the boiler and it is 200,000
> >> >Btus, then that "if" is big.
> >>
> >> Too right.
> >
> >And why not. If a boiler(s) is/are cost effective to buy then use
one/them.
> >Two combi's can be had for Ł800 that deliver 200,000 Btus.
>
> .... which won't run from a standard domestic supply.
200,000 Btus (approx 200 cu foot/hr will do). The max is 212 for a domestic
supply.
> With only 85 litres stored, the energy
> in comparison to the boiler is small
It doesn't matter, the result is what it is about.
> Like I said, a pointless exercise,
> and one that demonstrates that you
> are just pulling ideas out of the air
> that have no sound foundation in
> science or engineering.
You know nothing of HVAC so how do you know. Oh, I know you looked an O
level maths book. Duh!!
> >> >> It heats the water in the store
> >> >> which in turn heats the cold mains
> >> >> water via a plate heat exchanger.
> >> >
> >> >The water in the boiler goes straight
> >> >to the plate heat exchanger across the
> >> >top of a flat topped store. It can also
> >> >bypass the store if the pipoewrok is
> >> >arranged so. DO YOU UNDERSTAND?
> >>
> >> There will be a mixing effect, because
> >> there is one pump circulating
> >> between pump and store and another
> >> between store and heat exchanger.
> >
> >But the boiler will deliver hot water at say 80C, so mixing will be
minimal
> >as the store has a flat top and the flow pipe from the boiler is opposite
> >the flow pipe to the plate heat exchanger. The hot boiler supplied water
> >will go straight across the top and mixing will be so minimal it is not
> >worth talking about. You can also have the boiler feed the plate heat
> >exchanger direct and bypass the store. Did you read that bit in the last
> >post? If you did you didn't understand.
>
> I understood it all perfectly and commented
> on it. There will be mixing, but who is to
> say how much.
Me. And not much at all.
> For certain the heat transfer
> rate will be reduced compared
> with a direct connection.
> Having the boiler feed the heat
> exchanger just creates a combi which
> is a big yawn.
You must find out what a combi is. Reread and move your lips too.
> >> I had also thought of the redirect
> >> the boiler water through the plate
> >> exchanger idea.
> >
> >Please do not think. Just read and understand.
>
> That really is a scary suggestion.
I know the thought of you thinking.
> >> However, do you know of a
> >> product that implements
> >> this in practice?
> >
> >The DPS GVX. Can be sized up
> >to what you want. The standard product is 80
> >litres as it is aimed at a one bathroom house.
> >I believe it does CH & DHW.
>
> Questionable
Not Questionable, it does it.
> >Once again it is NOT A COMBI. A combi is all inside one casing, hence
the
> >word "combi", meaning "combination" boiler, combining DHW and CH. Read
the
> >above 10 times, it might sink in.
> I fully realise that it isn't a combi
Then why do keep saying it is?
> Did you ever study specific
> heat at school?
Yes, and it is clear you never studied any HVAC.
What amazed me about your type on these groups, is that you do actually
think you know what you are talking about, although a total amateur. A
prime example of a little knowledge is dangerous - in your case in your
pocket as you bought all that expensive needless kit.
IMM
"IMM" <abus...@easy.com> wrote in message
news:b8u7nt$v42$1...@newsg2.svr.pol.co.uk...
> > >The DPS GXV. Can be sized up
> > >to what you want. The standard product is 80
> > >litres as it is aimed at a one bathroom house.
> > >I believe it does CH & DHW.
> >
> > Questionable
>
> Not Questionable, it does it.
And I found this on DPS's web site. 170 litres of water at 45C in one go
from a 80 litre heat bank!!! Now if they had used an even larger boiler the
figures would be even better:.......
During a demonstration conducted using a GXV Heat Bank in conjunction with
the Vaillant VU186EH condensing boiler, the following procedure was
followed, and readings taken:
1.. The boiler was fired and left to fully heat up the stored water.
2.. The hot water outlet into the bath was fully opened.
3.. 120 litres was drawn at an average of 50°C and an average flow rate of
25 litres per minute.
4.. Without pause, a further 50 litres was drawn, to make a total of 170
litres of water at 45°C.
5.. The hot water outlet was closed and the system left for only 3 minutes
to recover.
6.. The hot water outlet into the bath was then opened again.
7.. A further 15 litres of 45°C water was drawn – sufficient for a basin
or sink.
8.. The hot water outlet was closed and the GXV Heat Bank left for 23
minutes to recover.
9.. The hot water outlet into the bath was again opened.
10.. A further 160 litres at 45°C was drawn off.
11.. The entire test was then repeated with very similar results.
Andy Hall
>> >Two combi's can be had for £800 that deliver 200,000 Btus.
>>
>> .... which won't run from a standard domestic supply.
>
>200,000 Btus (approx 200 cu foot/hr will do). The max is 212 for a domestic
>supply.
Leaving 4kW to run everything else. Be serious.
>
>> With only 85 litres stored, the energy
>> in comparison to the boiler is small
>
>It doesn't matter, the result is what it is about.
I already used that point.
>
>> Like I said, a pointless exercise,
>> and one that demonstrates that you
>> are just pulling ideas out of the air
>> that have no sound foundation in
>> science or engineering.
>
>You know nothing of HVAC so how do you know.
It works on a very few simple principles covered by first form
physics. Amazingly, the products on the market actually work using
these principles and have data sheets providing their operating
characteristics. Other aspects of products are pointed out as
features by the manufacturers and others. The user can decide quite
easily whether those are benefits or not when making a selection.
In that area I include things like whether or not overflows are
required, whether professional install is required and so on.
There are numerous web based and printed reference and design guides
that make it possible for anyone able to do simple arithmetic to make
an informed decision on the most appropriate system for their needs
and to select the appropriate components.
>Oh, I know you looked an O
>level maths book. Duh!!
Did you ever do O level maths as a matter of interest? Did you pass?
>> >>
>> >> There will be a mixing effect, because
>> >> there is one pump circulating
>> >> between pump and store and another
>> >> between store and heat exchanger.
>> >
>>
>> I understood it all perfectly and commented
>> on it. There will be mixing, but who is to
>> say how much.
>
>Me. And not much at all.
Not exactly an authoritative source, then.
>
>> For certain the heat transfer
>> rate will be reduced compared
>> with a direct connection.
>> Having the boiler feed the heat
>> exchanger just creates a combi which
>> is a big yawn.
>
>You must find out what a combi is. Reread and move your lips too.
In net terms that is what is created. The packaging is irrelevant.
>
>> >Once again it is NOT A COMBI. A combi is all inside one casing, hence
>the
>> >word "combi", meaning "combination" boiler, combining DHW and CH. Read
>the
>> >above 10 times, it might sink in.
>
>> I fully realise that it isn't a combi
>
>Then why do keep saying it is?
As I just pointed out, the packaging is irrelevant. In terms of
functionality, an equivalent to a combi is exactly what has been
created.
>
>> Did you ever study specific
>> heat at school?
>
>Yes, and it is clear you never studied any HVAC.
I really question whether you had any formal education at all. I
think it highly unlikely that it was of any further or higher level
since you seem unable to grasp even the most basic concepts of what is
happening in heat energy terms in any of these products. This is why
you keep introducing ridiculous ideas like huge boiler capacities and
tiny stores.
You seem to think that there is something clever to understand in the
variants of products that the industry produces. There isn't. They
still have to follow the basic laws of physics. It isn't necessary
to know every detail of every product to have a reasonable knowledge
and understanding of a field.
Knowledge of individual products is a short lived thing. What is far
more important is to be able to appreciate how they work and to
therefore determine whether manufacturer's claims are relevant.
>
>What amazed me about your type on these groups, is that you do actually
>think you know what you are talking about, although a total amateur.
I have never claimed to be anything other than an amateur in this
field, which after all is the essence of DIY. However, everything
that I have said I have been able to back up with sound engineering
and principles of physics. I do not pull ideas out of the air which
can't be substantiated.
You on the other hand persist in implying that you are some kind of
professional, when the evidence of your education and thought
processes don't support that assertion. When asked you consistently
evade the subject. That is not the behaviour of a professional,
unless they are not telling the truth or have something to hide.
> A
>prime example of a little knowledge is dangerous - in your case in your
>pocket as you bought all that expensive needless kit.
>
>
>
In fact in my case research and knowledge was appropriate and adequate
for what I needed to achieve. I didn't go into depth into industrial
systems because I was installing a domestic one against a set of
specific criteria. Those criteria have been met.
I might add that there isn't a single item that I am using that you
haven't recommended at one time or another.
Is Gucci in the HVAC business as well?
Andy Hall
>
>"IMM" <abus...@easy.com> wrote in message
>news:b8u7nt$v42$1...@newsg2.svr.pol.co.uk...
>
>> > >The DPS GXV. Can be sized up
>> > >to what you want. The standard product is 80
>> > >litres as it is aimed at a one bathroom house.
>> > >I believe it does CH & DHW.
>> >
>> > Questionable
>>
>> Not Questionable, it does it.
>
>And I found this on DPS's web site. 170 litres of water at 45C in one go
>from a 80 litre heat bank!!! Now if they had used an even larger boiler the
>figures would be even better:.......
>
I also found it some months ago.
The results are largely meaningless because they don't specify the
incoming mains water temperature. Without that, it isn't possible to
assess the performance.
They also only say that the flow rate was 25 litres/min in the initial
draw off not what it is for subsequent ones. Is it the same or did
they turn down the tap? Who knows.
I've been reading manufacturer's technical data sheets and application
examples for too many years not to spot what is NOT said as opposed to
what is.
I'm not easily impressionable either
IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> On Fri, 2 May 2003 17:50:42 +0100, "IMM" <abus...@easy.com> wrote:
>
>
> >> >Two combi's can be had for £800 that deliver 200,000 Btus.
> >>
> >> .... which won't run from a standard domestic supply.
> >
> >200,000 Btus (approx 200 cu foot/hr will do). The max is 212 for a
domestic
> >supply.
>
> Leaving 4kW to run everything else. Be serious.
Like a hob? What else is there on gas these days?
> >> Like I said, a pointless exercise,
> >> and one that demonstrates that you
> >> are just pulling ideas out of the air
> >> that have no sound foundation in
> >> science or engineering.
> >
> >You know nothing of HVAC so how do you know.
>
> It works on a very few simple
> principles covered by first form
> physics.
You have to understand the "engineering" process that is going on.
> Did you ever do O level maths as a matter of interest? Did you pass?
Science degree.
> >Me. And not much at all.
>
> Not exactly an authoritative source, then.
An expert in the field me boy!!!
> >You must find out what a combi is.
> > Reread and move your lips too.
>
> In net terms that is what is created.
> The packaging is irrelevant.
It is not, as a substantial amount of stored water is used. Combi's do not
store that amount of water. Got it?
> As I just pointed out, the packaging
> is irrelevant. In terms of
> functionality, an equivalent to a combi
> is exactly what has been created.
There are elements of a combi process there, but NO combi combines the
burner output and the output of the stored water. Also you can switch to a
replenishment mode that cuts in the burner when the store is near depleted.
No combi does that. Got it?
> >Yes, and it is clear you never
> >studied any HVAC.
>
> I really question whether you had
> any formal education at all. I
> think it highly unlikely that it was
> of any further or higher level
> since you seem unable to grasp
> even the most basic concepts of what is
> happening in heat energy terms in
> any of these products.
I know exactly what is happening in the physics side, when studying HVAC all
these are taught. . That is not the issue, so I don't go down that line.
You are attempting to make you know something by quoting maths. It is the
engineering to give a combined output that you can understand.
> This is why you keep introducing ridiculous
> ideas like huge boiler capacities and
> tiny stores.
The engineering. These ideas have been implemted in real life. It is just
that you have never heard of them.
> You seem to think that there is something
> clever to understand in the
> variants of products that the industry produces.
> There isn't.
But you can't understand it.
> >What amazed me about your type on
> >these groups, is that you do actually
> >think you know what you are talking about,
> >although a total amateur.
>
> I have never claimed to be anything
> other than an amateur in this
> field,
Well if you can't understand ask. If you still can't then just accept it.
> which after all is the essence of DIY.
> However, everything
> that I have said I have been able
> to back up with sound engineering
You don't have an enineering mind, that is clear.
> and principles of physics.
I liked O level too.
> I do not pull ideas out of the air which
> can't be substantiated.
I do not pull ideas out of the air. These are all tried and proven and you
just can't understand them.
> You on the other hand persist in
> implying that you are some kind of
> professional,
Yep!
> when the evidence of your education and thought
> processes don't support that assertion.
Thought process? You don't know anything about HVAC to know how the thought
process goes.
> When asked you consistently
> evade the subject.
Who I work for and my quals are my business.
> That is not the behaviour of a professional,
It is.
> I might add that there isn't a single item that I am using that you
> haven't recommended at one time or another.
All the items are great and all are fine depending on the application. Most
were not for yours.
> Is Gucci in the HVAC business as well?
Great!! Leather covered combi's. You came up with a great idea and didn't
know it because of your warped thought train.!!!
Andy Hall
>
>"Andy Hall" <an...@hall.nospam> wrote in message
>news:5ba5bv8er0phbvtan...@4ax.com...
>> On Fri, 2 May 2003 17:50:42 +0100, "IMM" <abus...@easy.com> wrote:
>>
>>
>> >> >Two combi's can be had for Ł800 that deliver 200,000 Btus.
>> >>
>> >> .... which won't run from a standard domestic supply.
>> >
>> >200,000 Btus (approx 200 cu foot/hr will do). The max is 212 for a
>domestic
>> >supply.
>>
>> Leaving 4kW to run everything else. Be serious.
>
>Like a hob? What else is there on gas these days?
There could easily be a hob (10-12kW) and perhaps a fire.
It's a pointless discussion anyway since I don't think many
householders are going to install 2 large boilers.... unless they are
trying to power a time portal of course.......
>
>> >> Like I said, a pointless exercise,
>> >> and one that demonstrates that you
>> >> are just pulling ideas out of the air
>> >> that have no sound foundation in
>> >> science or engineering.
>> >
>> >You know nothing of HVAC so how do you know.
>>
>> It works on a very few simple
>> principles covered by first form
>> physics.
>
>You have to understand the "engineering" process that is going on.
I do. Remember that I'm the engineering graduate of the two of us.
>
>> Did you ever do O level maths as a matter of interest? Did you pass?
>
>Science degree.
In and from?
>
>> >Me. And not much at all.
>>
>> Not exactly an authoritative source, then.
>
>An expert in the field me boy!!!
Evidence?
>
>> >You must find out what a combi is.
>> > Reread and move your lips too.
>>
>> In net terms that is what is created.
>> The packaging is irrelevant.
>
>It is not, as a substantial amount of stored water is used. Combi's do not
>store that amount of water. Got it?
No it wasn't. This case was specifically where the boilr was
connected directly to the plate heat exchanger with no storage
involved. Either you lost the track or you are deliberately trying
to confuse.
>
>> As I just pointed out, the packaging
>> is irrelevant. In terms of
>> functionality, an equivalent to a combi
>> is exactly what has been created.
>
>There are elements of a combi process there, but NO combi combines the
>burner output and the output of the stored water. Also you can switch to a
>replenishment mode that cuts in the burner when the store is near depleted.
>No combi does that. Got it?
I didn't ever say that it did.
>
>> >Yes, and it is clear you never
>> >studied any HVAC.
>>
>> I really question whether you had
>> any formal education at all. I
>> think it highly unlikely that it was
>> of any further or higher level
>> since you seem unable to grasp
>> even the most basic concepts of what is
>> happening in heat energy terms in
>> any of these products.
>
>I know exactly what is happening in the physics side, when studying HVAC all
>these are taught. . That is not the issue, so I don't go down that line.
Because you don't understand it perhaps??
>You are attempting to make you know something by quoting maths.
In fact this has to do with physics.
> It is the
>engineering to give a combined output that you can understand.
There's nothing more in it than the result of adding two energy
sources and the rate of transfer of energy from one place to another.
It's very simple stuff.
>
>> This is why you keep introducing ridiculous
>> ideas like huge boiler capacities and
>> tiny stores.
>
>The engineering. These ideas have been implemted in real life. It is just
>that you have never heard of them.
>
Can you provide examples that can be substantiated? If not then
it's a pointless remark.
>> You seem to think that there is something
>> clever to understand in the
>> variants of products that the industry produces.
>> There isn't.
>
>But you can't understand it.
I have. The issue is that you would like it to be more complex
than it actually is in order to appear knowledgable. Sorry, it
doesn't wash.
>
>> >What amazed me about your type on
>> >these groups, is that you do actually
>> >think you know what you are talking about,
>> >although a total amateur.
>>
>> I have never claimed to be anything
>> other than an amateur in this
>> field,
>
>Well if you can't understand ask.
I do my own independent checking of issues and always use more than
one source.
>If you still can't then just accept it.
If you really had been educated in science to degree level, you would
not be suggesting that someone who has should do that.
>
>> which after all is the essence of DIY.
>> However, everything
>> that I have said I have been able
>> to back up with sound engineering
>
>You don't have an enineering mind, that is clear.
Just an honours degree in engineering and a successful career.
>
>> I do not pull ideas out of the air which
>> can't be substantiated.
>
>I do not pull ideas out of the air. These are all tried and proven and you
>just can't understand them.
When pressed on most of them you either change the subject or can't
substantiate what you are saying. If all else fails you suggest
accepting what you say in blind faith.
Not very convincing.
>
>> You on the other hand persist in
>> implying that you are some kind of
>> professional,
>
>Yep!
>
>> when the evidence of your education and thought
>> processes don't support that assertion.
>
>Thought process? You don't know anything about HVAC to know how the thought
>process goes.
I do know professionals in the HVAC industry who successfully design
and implement small to large systems. They use sound engineering
principles which are instantly recognisable to an engineer of a
different discipline (electrical/electronic); and then sanity checks
are done on designs with the basic physics as it should be.
I don't see them making up things as they go along or pulling ideas
that they can't substantiate out of thin air.
I sent one a copy of one of your threads recently and we had quite a
good laugh about it. "Which planet is he on?" was one comment.
>
>> When asked you consistently
>> evade the subject.
>
>Who I work for and my quals are my business.
That's fine. You are entitled to take that position if you wish.
However, you can't then claim to have experience or qualification in
said subjects if you are not willing to provide evidence.
It has no credibility at all.
>
>> I might add that there isn't a single item that I am using that you
>> haven't recommended at one time or another.
>
>All the items are great and all are fine depending on the application. Most
>were not for yours.
You have no idea what my criteria were so can't comment.
>
>> Is Gucci in the HVAC business as well?
>
>Great!! Leather covered combi's. You came up with a great idea and didn't
>know it because of your warped thought train.!!!
>
That's one angle. I was thinking more in terms of your flavour of
the month suggestions.
IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> >> >> >Two combi's can be had for £800 that deliver 200,000 Btus.
> >> >>
> >> >> .... which won't run from a standard domestic supply.
> >> >
> >> >200,000 Btus (approx 200 cu foot/hr will do).
> >> >The max is 212 for a domestic supply.
> >>
> >> Leaving 4kW to run everything else. Be serious.
> >
> >Like a hob? What else is there on
> >gas these days?
>
> There could easily be a hob (10-12kW)
> and perhaps a fire.
OK two 90,000 Btue combis's used as system boilers @ 180,000.
> It's a pointless discussion
It is not as all this is highly cost effective, and more cost effective than
what you bought.
> >You have to understand the
> >"engineering" process that is going on.
>
> I do.
You don't!
> Remember that I'm the engineering
> graduate of the two of us.
You should get your money back.
> >An expert in the field me boy!!!
>
> Evidence?
Read the thread!
> >> >You must find out what a combi is.
> >> > Reread and move your lips too.
> >>
> >> In net terms that is what is created.
> >> The packaging is irrelevant.
> >
> >It is not, as a substantial amount
> >of stored water is used. Combi's do not
> >store that amount of water. Got it?
>
> No it wasn't. This case was specifically
> where the boilr was connected directly
> to the plate heat exchanger with no storage
> involved. Either you lost the track or you
> are deliberately trying to confuse.
I never once said that the boiler was directly connected to a plate heat
exchanger with no storage involved. Engineers know how to read and get the
conceptual point involved.
> >> As I just pointed out, the packaging
> >> is irrelevant. In terms of
> >> functionality, an equivalent to a combi
> >> is exactly what has been created.
> >
> >There are elements of a combi process
> >there, but NO combi combines the
> >burner output and the output of the stored
> >water. Also you can switch to a
> >replenishment mode that cuts in the burner
> >when the store is near depleted.
> >No combi does that. Got it?
>
> I didn't ever say that it did.
I just explained how it works and you are right you never said that at all.
> >I know exactly what is happening in
> >the physics side, when studying HVAC all
> >these are taught. . That is not the issue,
> >so I don't go down that line.
>
> Because you don't understand it perhaps??
I repeat: "I know exactly what is happening in the physics side, when
studying HVAC all these are taught." If Imsay things twice it may sink in.
> > It is the engineering to give a
> > combined output that you can understand.
>
> There's nothing more in it than
> the result of adding two energy
> sources and the rate of transfer of
> energy from one place to another.
> It's very simple stuff.
Yet you can't realise the benefits.
> >> This is why you keep introducing ridiculous
> >> ideas like huge boiler capacities and
> >> tiny stores.
> >
> >The engineering. These ideas have
> >been implemted in real life. It is just
> >that you have never heard of them.
>
> Can you provide examples that can
> be substantiated? If not then
> it's a pointless remark.
I pointed you to the DPS site. Read it as most is in there except the mode
switching of combined and replenished.
> >> You seem to think that there is something
> >> clever to understand in the
> >> variants of products that the industry produces.
> >> There isn't.
> >
> >But you can't understand it.
>
> I have.
You haven't. All you have done is attempt to justify a poor decision in
your own setup.
> >> >What amazed me about your type on
> >> >these groups, is that you do actually
> >> >think you know what you are talking about,
> >> >although a total amateur.
> >>
> >> I have never claimed to be anything
> >> other than an amateur in this
> >> field,
> >
> >Well if you can't understand ask.
>
> I do my own independent checking of
> issues and always use more than
> one source.
And still screwed it up.
> >If you still can't then just accept it.
>
> If you really had been educated in
> science to degree level, you would
> not be suggesting that someone who
> has should do that.
If they can't understand then just accept it, no point in going further.
> >> which after all is the essence of DIY.
> >> However, everything
> >> that I have said I have been able
> >> to back up with sound engineering
> >
> >You don't have an enineering mind, that is clear.
>
> Just an honours degree in engineering
> and a successful career.
In computer networks!!!!!!!
> >> I do not pull ideas out of the air which
> >> can't be substantiated.
> >
> >I do not pull ideas out of the air.
> >These are all tried and proven and you
> >just can't understand them.
>
> When pressed on most of them
> you either change the subject or can't
> substantiate what you are saying.
I don't change the subject, I just don't go down blind alleys as you do.
> I do know professionals in the HVAC
> industry who successfully design
> and implement small to large systems.
> They use sound engineering
> principles which are instantly recognisable
> to an engineer of a different discipline
> (electrical/electronic); and then sanity checks
> are done on designs with the basic physics
> as it should be.
No modern applications engineer goes back to basic physics. It is all
boilerplate.
> I sent one a copy of one of your
> threads recently and we had quite a
> good laugh about it. "Which planet
> is he on?" was one comment.
He is obviously on yours, wherever that is.
> >> Is Gucci in the HVAC business as well?
> >
> >Great!! Leather covered combi's. You
> >came up with a great idea and didn't
> >know it because of your warped thought train.!!!
>
> That's one angle.
You have no imagination or vision whatsoever, you would make a basic
plodding, do as we have always done engineer. Sad really. Sad.
IMM
news:1fue1c2.ere2i514iha2zN%%steve%@malloc.co.uk...
> IMM <abus...@easy.com> wrote:
>
> > You don't!
> >
> > > Remember that I'm the engineering
> > > graduate of the two of us.
> >
> > You should get your money back.
> >
> > > >An expert in the field me boy!!!
> > >
> > > Evidence?
> >
> > Read the thread!
>
> degree" and the institution that awarded it?
My business.
> Tell me, how did you manage
> to get onto a science degree
> course without 'O' level mathematics?
You can't get on without mathematics.
I have O level and A. Did calulus too. All fun.
IMM
"Steve Firth" <usen...@malloc.co.uk> wrote in message
news:1fue3qu.urj3fx6cdc7mN%%steve%@malloc.co.uk...
> IMM <abus...@easy.com> wrote:
>
> > > Why did you snip, and not answer the question about your "Science
> > > degree" and the institution that awarded it?
> >
> > My business.
>
> there's no such thing as a degree in Science, all that's being asked is
> which science.
>
> > > Tell me, how did you manage
> > > to get onto a science degree
> > > course without 'O' level mathematics?
> >
> > You can't get on without mathematics.
> > I have O level and A. Did calulus too. All fun.
>
> maths, how clever of you.
Thank you.
Martin Angove
"IMM" <abus...@easy.com> wrote:
>
> Well if you can't understand ask.
Good idea...
> If you still can't then just accept it.
>
Really bad, scary idea. How about a "philosophy" thread?
:-)
Hwyl!
M.
--
Martin Angove (it's Cornish for "Smith") - ARM/Digital SA110 RPC
See the Aber Valley -- http://www.tridwr.demon.co.uk/abervalley.html
... Sometimes you just have to say 'What the heck'
Martin Angove
"IMM" <abus...@easy.com> wrote:
>
> "Andy Hall" <an...@hall.nospam> wrote in message
> news:4q87bv4itopu2bnc1...@4ax.com...
>
> >
> > No it wasn't. This case was specifically
> > where the boilr was connected directly
> > to the plate heat exchanger with no storage
> > involved. Either you lost the track or you
> > are deliberately trying to confuse.
>
> I never once said that the boiler was directly connected to a plate heat
> exchanger with no storage involved. Engineers know how to read and get the
> conceptual point involved.
>
I'm afraid that you did. There are probably a lot of people "lurking" on
this thread who have read your posts and probably came to the same
conclusion as Andy. Let me refresh your memory:
In message <b8rh3o$427$1...@news6.svr.pol.co.uk>,
"IMM" <abus...@easy.com> wrote:
[when the heat bank cools...]
> The output of the boiler goes directly to heat the incoming mains
> cold water, it does not in an unvented cylinder.
In message <b8thb1$fbu$1...@newsg2.svr.pol.co.uk>,
"IMM" <abus...@easy.com> wrote:
>
> "Andy Hall" <an...@hall.nospam> wrote in message
> news:6fi2bvk6o3f34e515...@4ax.com...
>
>
> > It heats the water in the store
> > which in turn heats the cold mains
> > water via a plate heat exchanger.
>
> The water in the boiler goes straight to the plate heat exchanger across the
> top of a flat topped store. It can also bypassthe store if the pipoewrok is
> arranged so. DO YOU UNDERSTAND?
By my reading, you said it *twice*. On two separate occasions. If you
did not mean what I appear to have understood, could you please explain
exactly what you *did* mean?
Mae 'y mhen yn droi!
Hwyl!
M.
--
Martin Angove (it's Cornish for "Smith") - ARM/Digital SA110 RPC
See the Aber Valley -- http://www.tridwr.demon.co.uk/abervalley.html
... Sure, drinking kills brain cells, but only the weak ones.
IMM
> IMM <abus...@easy.com> wrote:
>
> > > Calulus? That's a new one on me, and you took it as well as A level
> > > maths, how clever of you.
> >
> > Thank you.
>
NO. I have them.
> What a surprise.
No it is not I am clever and all that.
> And you're too thick to realise the only one who falls for
> your bullshit is you.
Sir, you are a cad a bounder and a total idiot too.
IMM
"Martin Angove" <MJAn...@tridwr.demon.co.uk> wrote in message
news:92e4e4ec4...@tridwr.demon.co.uk...
You kust read again:
" I never once said that the boiler was directly connected to a plate heat
exchanger with no storage involved. Engineers know how to read and get the
conceptual point involved."
The key word is "no". The boilers heat does go to the plate but also heat
from the store too. It was clear if you had been keeping up with the
thread. Andy lost it on post 3.
IMM
> > Well if you can't understand ask.
>
> Good idea...
>
> > If you still can't then just accept it.
>
> Really bad, scary idea. How about a "philosophy" thread?
No. Just accept what I say about the matter is best.
Andy Hall
>
>> and perhaps a fire.
>
>OK two 90,000 Btue combis's used as system boilers @ 180,000.
>
>> It's a pointless discussion
>
>It is not as all this is highly cost effective, and more cost effective than
>what you bought.
If this were such a good idea, large numbers of installations as you
describe would be done. The idea is so ridiculous that it doesn't
merit further discussion.
>
>> >An expert in the field me boy!!!
>>
>> Evidence?
>
>Read the thread!
It gives me all the evidence I need to appraise your "expertise"
>>
>> No it wasn't. This case was specifically
>> where the boilr was connected directly
>> to the plate heat exchanger with no storage
>> involved. Either you lost the track or you
>> are deliberately trying to confuse.
>
>I never once said that the boiler was directly connected to a plate heat
>exchanger with no storage involved. Engineers know how to read and get the
>conceptual point involved.
If this were the House of Commons I would suggest that the Honourable
Gentleman is misleading the house. Since it isn't, you either have
a very short memory or are deliberately telling lies. You mentioned
connecting the boiler to the heat exchanger via the store in such a
way that the heat goes directly from one to the other at least twice.
You then went on to talk about literal direct connections between the
two.
As far as conceptual points are concerned, I don't think that you
could spot anything conceptual if it stood up and bit your nose.
>
>> > It is the engineering to give a
>> > combined output that you can understand.
>>
>> There's nothing more in it than
>> the result of adding two energy
>> sources and the rate of transfer of
>> energy from one place to another.
>> It's very simple stuff.
>
>Yet you can't realise the benefits.
All that you have described is a feature of a heat store.
An equivalent effect can be achieved from a HW storage cylinder
of 20% greater volume.
Whether these are benefits is in the perception of the recipient of
the information - typically the purchaser.
>
>> >> This is why you keep introducing ridiculous
>> >> ideas like huge boiler capacities and
>> >> tiny stores.
>> >
>> >The engineering. These ideas have
>> >been implemted in real life. It is just
>> >that you have never heard of them.
>>
>> Can you provide examples that can
>> be substantiated? If not then
>> it's a pointless remark.
>
>I pointed you to the DPS site. Read it as most is in there except the mode
>switching of combined and replenished.
There is some useful information on that site. However since the
product specifications are not completely laid out and pieces are
missing from the test example that they give, further checking would
be needed to decide whether the results are as good as implied.
I don't see any examples of huge boiler capacity and tiny stores.
>
>> >If you still can't then just accept it.
>>
>> If you really had been educated in
>> science to degree level, you would
>> not be suggesting that someone who
>> has should do that.
>
>If they can't understand then just accept it, no point in going further.
You're right there.
>
>> >> which after all is the essence of DIY.
>> >> However, everything
>> >> that I have said I have been able
>> >> to back up with sound engineering
>> >
>> >You don't have an enineering mind, that is clear.
>>
>> Just an honours degree in engineering
>> and a successful career.
>
>In computer networks!!!!!!!
... and RF design, microprocessor control system implementation, power
electronics, semiconductor applications, audio system automation,
operating systems, databases, applications, network design and
implementation, video technology, support and services, marketing,
.....
>>
>> When pressed on most of them
>> you either change the subject or can't
>> substantiate what you are saying.
>
>I don't change the subject, I just don't go down blind alleys as you do.
>
You don't even seem to remember when you do change the subject.
>
>> I do know professionals in the HVAC
>> industry who successfully design
>> and implement small to large systems.
>> They use sound engineering
>> principles which are instantly recognisable
>> to an engineer of a different discipline
>> (electrical/electronic); and then sanity checks
>> are done on designs with the basic physics
>> as it should be.
>
>No modern applications engineer goes back to basic physics. It is all
>boilerplate.
It's always good practice to do a basic principles sanity check.
This avoids costly mistakes.
>
>> I sent one a copy of one of your
>> threads recently and we had quite a
>> good laugh about it. "Which planet
>> is he on?" was one comment.
>
>He is obviously on yours, wherever that is.
Seemingly the one that the rest of us are on.
>
>
>You have no imagination or vision whatsoever, you would make a basic
>plodding, do as we have always done engineer. Sad really. Sad.
>
>
I suspect that the boot's on the other foot there, don't you.
Martin Angove
"IMM" <abus...@easy.com> wrote:
I tried asking this in another thread and no-one has given me the answer
I expect you are about to give, so perhaps you can enlighten me:
Are you saying that the boiler water passes through the heat exchanger
on its way to the coil in the heat bank; that the boiler water is
*diverted* to pass through the heat exchanger once the water in the heat
bank is no longer able to heat the tap water sufficiently, or that the
boiler water goes directly to the coil in the heat bank *always* and
never directly enters the heat exchanger?
Just a poor confused soul :-)
Hwyl!
M.
--
Martin Angove (it's Cornish for "Smith") - ARM/Digital SA110 RPC
See the Aber Valley -- http://www.tridwr.demon.co.uk/abervalley.html
... 1st we shoot all the lawyers, 2nd we strangle them, 3rd..
Andy Hall
<MJAn...@tridwr.demon.co.uk> wrote:
>>
>>
>
>I tried asking this in another thread and no-one has given me the answer
>I expect you are about to give, so perhaps you can enlighten me:
>
>Are you saying that the boiler water passes through the heat exchanger
>on its way to the coil in the heat bank; that the boiler water is
>*diverted* to pass through the heat exchanger once the water in the heat
>bank is no longer able to heat the tap water sufficiently, or that the
>boiler water goes directly to the coil in the heat bank *always* and
>never directly enters the heat exchanger?
>
>Just a poor confused soul :-)
... and you're asking IMM to help improve that situation?
Have a look at
http://www.albion-online.co.uk/mainsflow%20x.html
for an illustration of direct and indirect stores.
In some designs like the DPS ones, the secondary heat exchanger, which
is shown as a coil in the Albion illustration is a plate heat
exchanger, external to the store cylinder. These have a better
transfer rate than most coils.
In the indirect case, the boiler primary water never reaches the
secondary heat exchanger anyway since the cylinder water forms an
extra stage of heat transfer. This design would be useful to the OP
of this thread, since the primary could be run sealed and there could
be radiators above the level of the store. The direct store is
vented and would require an FE tank above the highest radiator. There
was no room for that.
With a direct store, as long as the boiler connections and the heat
exchanger connections are both near top and bottom of the store, it
can be argued to a point that once the store is empty of its own heat
that stratification would cause a "flow" of hot boiler water across
the top of the store and cool across the bottom. However, there is
bound to be some mixing due to pump action because the flow rates
between boiler and store and store and secondary heat exchanger won't
be the same. Therefore some energy will go into the store - not all
to the heat exchanger.
It would also be technically possible with a direct store to arrange
that the boiler primary water is delivered directly to the secondary
exchanger directly by rigging up a diverting arrangement of three
motorised 2 port zone valves. Draw it as two connections onto the
store with a valve on each and a bridge between the two with a valve
on that. The boiler connection would go to one junction between
valves and the heat exchanger on the other. In normal operation the
valves leading to the store would be open and the bridging one closed,
putting the store in the circuit. When the store ran out close the
two valves and open the bridging one, connecting boiler directly to
heat exchanger. This could be controlled via a thermostat on the
store and the auxiliary contacts of the valves. It would mean that
once the store was out, all the boiler energy would go to the heat
exchanger, giving better performance than if the store is in the
middle. This creates the functional equivalent of a combi boiler
with two heat exchangers between the burner and the secondary water
rather than one. My point here was this is not that interesting if
you are comparing what the store plus the boiler does compared with
the boiler alone. The thing should be designed with enough capacity
that you never run out of store energy.
If you look at the indirect case this can't be done.
Unless the primary coil reaches the top of the store at the top rather
than part way up there will be convection in the cylinder and again
the store will be being replenished as well as heat used through the
secondary exchanger. You obviously can't do the direct connect hook
up.
There are undoubtedly cases where thermal stores are useful. One is
in mixing energy from different sources and at different temperatures
such as solar and solid fuel; or where the energy is not economically
available all day like with electricity.
My contention is that when you have a continuously available single
energy source such as gas, from an energy perspective you gain little
vs. a good cylinder arrangement other than perhaps a 20% space saving.
With a condensing boiler, if the store is used as part of the space
heating, the efficiency is going to be worse because of the
temperature required in the store to make it worthwhile. If it's for
DHW only then we are back to the 20% space saving.
There are some other practical advantages such as no need for an
overflow or discharge and that the store can be DIY installed. These
can be big decision influencing issues.
There are other things that can be done with plate heat exchangers
like putting one on the primary of the boiler and then having a HW
cylinder on the secondary side with a potable water pump - e.g. a
Grundfos bronze one. This would transfer energy into the cylinder
more effectively than a copper coil - even a fast recovery one.
I use one very effectively between two parts of my heating system to
separate the house from the workshop heating, so I can say that they
work well.
>
>Hwyl!
>
>M.
IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> On Sat, 3 May 2003 14:26:37 +0100, "IMM" <abus...@easy.com> wrote:
>
> >
>
> >> and perhaps a fire.
> >
> >used as system boilers @ 180,000.
> >
> >> It's a pointless discussion
> >
> >It is not as all this is highly cost effective,
> >and more cost effective than
> >what you bought.
>
> If this were such a good idea,
> large numbers of installations as you
> describe would be done.
The industry is locked into set ways. Why do they put boilers in kitchens,
taking up cupboard space, when the loft is empty?
> All that you have described is a feature of a heat store.
> An equivalent effect can be achieved from a HW storage cylinder
> of 20% greater volume.
Read all this thread agian - 4 times.
> >I pointed you to the DPS site. Read it as
> >most is in there except the mode
> >switching of combined and replenished.
>
> There is some useful information on that site. However since the
> product specifications are not completely laid out and pieces are
> missing from the test example that they give, further checking would
> be needed to decide whether the results are as good as implied.
> I don't see any examples of huge boiler capacity and tiny stores.
Anyone who knows about HVAC can see that larger output, snallish cased
cheapish boilers can be mated to these heat banks, lowering the size. In
fact the GXV was designed with small storage in mind, to fit into small
British houses. With the direct version, there is no limitation on boiler
size. Not being inthe business and poor at grasping concepts, You obviously
can't see this.
Go to DPS and say: Sir, I want one of your 80 litre GXV heat banks and want
to put two 80,000 Btus boioers on it, can you install the correct sized
tapping for me. They will say: Yes Sir, it will work superbly and we will
install the correct sized tappings for the boilers.
> >> Just an honours degree in engineering
> >> and a successful career.
> >
> >In computer networks!!!!!!!
>
> ... and RF design, microprocessor control system implementation, power
> electronics, semiconductor applications, audio system automation,
> operating systems, databases, applications, network design and
> implementation, video technology, support and services, marketing,
I see NO HVAC. Operating systems. What operating system have you
fdesigned/implemeted? Don't porkie tell!!!!!
> >No modern applications engineer
> >goes back to basic physics. It is all
> >boilerplate.
>
> It's always good practice to do a
> basic principles sanity check.
> This avoids costly mistakes.
They go from boiler plate, which is tables, graphs, etc, I repeat: No modern
applications engineer goes back to basic physics. It is all boilerplate".
No one has the time to piss around proving the proven boiler plate wrong.
That is the stuff they do at college.
> >> I sent one a copy of one of your
> >> threads recently and we had quite a
> >> good laugh about it. "Which planet
> >> is he on?" was one comment.
> >
> >He is obviously on yours, wherever that is.
>
> Seemingly the one that the rest of us are on.
Tell your confused engineer to ask Qs on here and I will put him right.
IMM
> I tried asking this in another thread and no-one has given me the answer
> I expect you are about to give, so perhaps you can enlighten me:
>
> Are you saying that the boiler water passes through the heat exchanger
> on its way to the coil in the heat bank; that the boiler water is
> *diverted* to pass through the heat exchanger once the water in the heat
> bank is no longer able to heat the tap water sufficiently, or that the
> boiler water goes directly to the coil in the heat bank *always* and
> never directly enters the heat exchanger?
There is confusion about this topic. Firstly domestic thermal stores are
split into two categories:
1. Thermal Store
A store of water heated by a boiler directly or indirectly, open vented or
sealed, which is cylindrical and has a spiral coil inside which has cold
mains water running through which is heated instantly by transferring heat
from the stored water which the coil is immersed. The Albion Mainsflow is a
thermal store. Explanation of a simple thermal store:
http://www.albion-online.co.uk/mainsflow%20x.html
2. Heat Bank
These have a store of water as above, but the heat transfer is via a high
efficiency plate heat exchanger, which is typically fitted externally to the
store of water (some were/are inside the store, but these are rare). A
simple cheap CH pump used to take heated stored water from the store to the
plate heat exchanger. The store of water does not have to be cylindrical,
it can be virtually any shape (the Worcester-Bosch HighFlow combi has an odd
shaped one at its base). Range Cylinders now make a heat bank dropping the
thermal store: http://tinyurl.com/axim
Very few makers are left making coil transfer thermal stores. DPS only make
heat banks, and can make to custom designs or off-the-shelf. Explanation of
a heat bank:
http://www.heatweb.com/products/cylinders/heatbank/heatbank.htm
That is the difference in the basic operation. Heat banks are more
efficient, the plate heat exchangers are resistant to scale build up and can
be easily removed for de-scaling. A heat bank gives far high flow rates
than a simple thermal store. Thermal stores/heat banks, score over unvented
cylinders on many points: no high pressure storage, no BBA approved fitting,
faster recovery, can "combine" the energy of the boiler and the stored hot
water to give high flow rates, will "never" run out of hot water if
configured correctly, no complex high pressure controls, no air pocket to
maintain in the top of the cylinder, etc, etc.
Both types reduce/eliminate inefficient boiler cycling. Both types can also
be DHW only or "integrated" supplying DHW and CH. The CH is supplied by
taking flow and return pipes off the bottom of the store.
Both types can have electric immersion backup for DHW and CH, depending on
the immersion size of course.
The beauty of a heat bank is that with a little imagination the energy of
the boiler and the energy of the stored water can be "combined" to instantly
heat cold mains water (the view is: if the power is there in the boiler then
use it, don't let it sit there just topping up a water store). This reduces
the size of the store required, with the 80 litre DPS GXV it can fit under a
kitchen worktop, supply 170 litres of 45C water at 25 litres/minutes flow
rate, using a 40-50,000 Btus directly connected boiler. Very impressive.
You will ,never run out of hot water, although the flow will reduce when the
heat bank runs out of hot water).
Being direct (the boiler and heat bank use the same water) any sized boiler
can be fitted to the heat bank. If you uprate the boiler to 100,000 Btus
the DHW performance is even better (a domestic gas supply can give 212 cu
ft/hr, so you can use two cheap boilers giving 190,000 Btus (190 cu ft/hr),
with staggering DHW performance and boiler backup too just using a 80 litre
heat bank. That is if you want to pay the extra for the performance and the
boiler backup. When no DHW is being drawn off then the boiler replenished
the store.
This type of "combined" boiler/stored water heat bank can be sized up, so
that a smallish boiler can be fitted and most of the energy used to heat DHW
is via the water heat store, or you can downsize the store to fit into a
small space and use a powerful boiler, which don't take up much more space
than smallish boiler. Or if you want real instant staggering performance,
as I previously mentioned, use two cheap boilers, which will give backup if
one is down, and just the boilers alone will give around 20-22 litres DHW if
the heat banks energy is exhausted.
IMM
> ... and you're asking IMM to help improve that situation?
He is and quite rightly so, as what is written below is disjointed utter
confusion. Andy you disappoint.
< snip utter confusion >
IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> With a direct store, as long as the boiler connections and the heat
> exchanger connections are both near top and bottom of the store, it
> can be argued to a point that once the store is empty of its own heat
> that stratification would cause a "flow" of hot boiler water across
> the top of the store and cool across the bottom. However, there is
> bound to be some mixing due to pump action because the flow rates
> between boiler and store and store and secondary heat exchanger won't
> be the same. Therefore some energy will go into the store - not all
> to the heat exchanger.
If the secondary pump (the one to the plate heat exchanger) is at a geater
head than the primary pump (from the boiler), any heat delivered by the
boiler will go across the top of a flat store and into the pipe opposite
leading to the plate heat exchanger.
If the external pipes are arranged correctly the boilers heat can bypass the
store and go directly to the plate heat exchanger.
> It would also be technically possible with a direct store to arrange
> that the boiler primary water is delivered directly to the secondary
> exchanger directly by rigging up a diverting arrangement of three
> motorised 2 port zone valves. Draw it as two connections onto the
> store with a valve on each and a bridge between the two with a valve
> on that. The boiler connection would go to one junction between
> valves and the heat exchanger on the other. In normal operation the
> valves leading to the store would be open and the bridging one closed,
> putting the store in the circuit. When the store ran out close the
> two valves and open the bridging one, connecting boiler directly to
> heat exchanger. This could be controlled via a thermostat on the
> store and the auxiliary contacts of the valves. It would mean that
> once the store was out, all the boiler energy would go to the heat
> exchanger, giving better performance than if the store is in the
> middle. This creates the functional equivalent of a combi boiler
> with two heat exchangers between the burner and the secondary water
> rather than one. My point here was this is not that interesting if
> you are comparing what the store plus the boiler does compared with
> the boiler alone. The thing should be designed with enough capacity
> that you never run out of store energy.
Andy, you are starting to think a little, this is encouraging in a strange
way. Your solution is very complex, as the same cane be achieved by having
different head settings on two pumps.
You say: "The thing should be designed with enough capacity that you never
run out of store energy.". Not so. You arrange so that all the energy
available to you is used - the heat store and boiler together.
> My contention is that when you have a
> continuously available single
> energy source such as gas, from an
> energy perspective you gain little
> vs. a good cylinder arrangement other
> than perhaps a 20% space saving.
Andy, not there on this one. Disappointing again. But keep the thinking up.
> With a condensing boiler, if the store
> is used as part of the space
> heating, the efficiency is going to
> be worse because of the
> temperature required in the store to
> make it worthwhile.
Again you disappoint. A condenser will "overall" have greater efficiencies
on a heat bank, as it operates in a set environment at all times. Having a
no-flame boiler on heat banks and great efficiencies are had.
If a CH system is engineered to get the best from a condenser by having
expensive large oversized rads then a condenser will give great efficiencies
and a DHW only heat bank will suffice.
> There are some other practical advantages
> [of heat banks] such as no need for an
> overflow or discharge and that the store can
> be DIY installed. These can be big decision
> influencing issues.
Not arf.
> There are other things that can be done
> with plate heat exchangers
> like putting one on the primary of the
> boiler and then having a HW
> cylinder on the secondary side with a
> potable water pump - e.g. a
> Grundfos bronze one. This would
> transfer energy into the cylinder
> more effectively than a copper coil - even
> a fast recovery one.
Why would you want to that when a heat bank can do that even better all in
one small package.
> I use one very effectively between two
> parts of my heating system to
> separate the house from the workshop
> heating, so I can say that they work well.
Why do you separate them? What is wrong with running the same water in the
workshop and the house. Simpler and cheaper too.
IMM
> With a direct store, as long as the boiler connections and the heat
> exchanger connections are both near top and bottom of the store, it
> can be argued to a point that once the store is empty of its own heat
> that stratification would cause a "flow" of hot boiler water across
> the top of the store and cool across the bottom. However, there is
> bound to be some mixing due to pump action because the flow rates
> between boiler and store and store and secondary heat exchanger won't
> be the same. Therefore some energy will go into the store - not all
> to the heat exchanger.
If the secondary pump (the one to the plate heat exchanger) is at a greater
head than the primary pump (from the boiler), any heat delivered by the
boiler will go across the top of a flat store and into the pipe opposite
leading to the plate heat exchanger.
If the external pipes are arranged correctly the boilers heat can bypass the
store and go directly to the plate heat exchanger.
> It would also be technically possible with a direct store to arrange
> that the boiler primary water is delivered directly to the secondary
> exchanger directly by rigging up a diverting arrangement of three
> motorised 2 port zone valves. Draw it as two connections onto the
> store with a valve on each and a bridge between the two with a valve
> on that. The boiler connection would go to one junction between
> valves and the heat exchanger on the other. In normal operation the
> valves leading to the store would be open and the bridging one closed,
> putting the store in the circuit. When the store ran out close the
> two valves and open the bridging one, connecting boiler directly to
> heat exchanger. This could be controlled via a thermostat on the
> store and the auxiliary contacts of the valves. It would mean that
> once the store was out, all the boiler energy would go to the heat
> exchanger, giving better performance than if the store is in the
> middle. This creates the functional equivalent of a combi boiler
> with two heat exchangers between the burner and the secondary water
> rather than one. My point here was this is not that interesting if
> you are comparing what the store plus the boiler does compared with
> the boiler alone. The thing should be designed with enough capacity
> that you never run out of store energy.
Andy, you are starting to think a little, this is encouraging in a perverse
way. Your solution is very complex, as the same can be achieved by having
different head settings on two pumps.
You say: "The thing should be designed with enough capacity that you never
run out of store energy.". Not so. You arrange so that all the energy
available to you is used - the heat store and boiler are collectively
harnessed.
> My contention is that when you have a
> continuously available single
> energy source such as gas, from an
> energy perspective you gain little
> vs. a good cylinder arrangement other
> than perhaps a 20% space saving.
Andy, not there on this one. Disappointing again. But keep the thinking up.
> With a condensing boiler, if the store
> is used as part of the space
> heating, the efficiency is going to
> be worse because of the
> temperature required in the store to
> make it worthwhile.
Again you disappoint. A condenser will "overall" have greater efficiencies
on a heat bank, as it operates in a set environment at all times and is
NEVER in an inefficient high temp mode. Having a no-flame boiler on heat
banks, rather than condesning boilers, and great efficiencies are had.
If a CH system is engineered to get the best from a condenser by having
expensive large oversized rads then a condenser will give great efficiencies
and a DHW only heat bank will suffice.
> There are some other practical advantages
> [of heat banks] such as no need for an
> overflow or discharge and that the store can
> be DIY installed. These can be big decision
> influencing issues.
Not arf.
> There are other things that can be done
> with plate heat exchangers
> like putting one on the primary of the
> boiler and then having a HW
> cylinder on the secondary side with a
> potable water pump - e.g. a
> Grundfos bronze one. This would
> transfer energy into the cylinder
> more effectively than a copper coil - even
> a fast recovery one.
Why would you want to that when a heat bank can do that even better all in
one small package.
> I use one very effectively between two
> parts of my heating system to
> separate the house from the workshop
> heating, so I can say that they work well.
Why do you separate them? What is wrong with running the same water in the
workshop and the house. Simpler and cheaper too.
Andy,
I recently converted a quick recovery indirect 120 litre cylinder to a DHW
only heat bank.
The cylinder was insulated to part L so little heat loss.
1. A 1" Surrey flange was used in the top tapping if the cylinder.
2. The boilers flow connect to the Surrey flange port that is immersed in
the cylinder water. I drilled a few holes in the protruding tube that goes
into the water to ensure heat dissipation and that the hot water from the
boiler only stays in the cylinders dome, not being pumped to the bottom of
the cylinder. the protruding tube has a pate over the end to stop the water
heat right to the bottom of the cylinder.
3. The plate heat exchanger was taken from the other connection of the
Surrey flange on the top of the cylinder then to the plate and then to the
pump and back into the bottom cylinder port (the cylinder had two bottom
ports). I made a diffuser by inserting 22mm pipe into the cylinder and
drilling holes in and stopping up the end. I filed down the inside of a
brass compression fitting removing the pipe stop so the pipe can go straight
through. This will spread the returning water mainly down, so it will not
upset stratification in the cylinder.
4. The boilers flow was to the Surrey flange of cylinder and the return
from the other port. No diffuser is required for the bottom port. A
Reliance Heatguard UFH bending valve was fitted between the flow and the
return pipes near the boiler, as performance is best when near. The boiler
is 18 years old and 85,000 Btus.
5. Two cylinder stats were used to give a long efficient recovery burn.
One stat top and one just above the boilers return pipe of the cylinder. A
switch was used to cut out the top stat and leave the bottom stat
operational. This switch give replenishing mode or "combined mode" of
boiler and stored water to heat the incoming cold mains.
6. The cold mains direct from the cold ains stop cock with no tee offs, was
taken into a flow switch then into the bottom connection of the coil, out
the top of the coil, into the plate heat exchanger and then to a the DHW
blending valve set to 52C (they can adjust it to suit themselves). Before
and after the flow switch tees were inserted and between an appliance
isolation valve fitted (the one you need a screwdriver to return off). This
allowed some mains water to bypass the flow switch. What this does is allow
small amounts of water to be heated by the internal coil and the plate only
is switched in when there is large flows, so that when filling a basin the
DHW pump is not switched in. It takes a little setting up on commissioning.
This valve reduces the on/off DHW pump operation giving lonmgevity to the
pump. The cold water being pre-heated by the internal coil and then the
plate heat exchanger gives fantastic DHW flow rates, and
7. An auto air vent was instaled at the top of the cylinders pipework above
the Surrey flange. The existing open vent to the boiler was left as was the
existing feed and F&E tank.
A phosphor de-scalar was installed in the incoming mains pipe.
This was for a relative. Their existing 180 litre cylinder was leaking and
they were contemplating a power shower in each of the two bathrooms. This
was a cheaper alternative than two power shower pumps and a new cylinder.
The new smaller heat bank cylinder gives them more airing cupboard space,
which they are delighted with.
The performance is brilliant and they are delighted with the mains fed
showers and no vibrating power shower pump noise. They have filled two
baths simultaneously with no problems. Intially I set heat bank to 80C,
with the boiler at 82C, and the Reliance blending valve keeps the return at
71C. I may set the boiler to 82C, the heat banks to 75C and blender to 71C,
and see how it works. If OK for ther heavy use then leave it. This will
reduce standing heat losses.
I kept the large tank in the loft, as it is still OK, supplying the toilets
only. So when there is a water outage they have 150 gallons of toilet water
in store and some water backup. Maybe over the top, but is was already
there so I used to it. I would not fit one in a new installation.
I installed isolation valves on heavy usage appliances, as the washing
machine, and throttled this back so it will not rob showers and baths of hot
water.
As all is off the same mains pipes mixer taps were installed in basins. They
may go for a condenser in few years time, when it is a matter of just
adjusting the boiler and heat banks settings. I all the info taped on the
side of the cylinder in case.
IMM
> With a direct store, as long as the boiler connections and the heat
> exchanger connections are both near top and bottom of the store, it
> can be argued to a point that once the store is empty of its own heat
> that stratification would cause a "flow" of hot boiler water across
> the top of the store and cool across the bottom. However, there is
> bound to be some mixing due to pump action because the flow rates
> between boiler and store and store and secondary heat exchanger won't
> be the same. Therefore some energy will go into the store - not all
> to the heat exchanger.
If the secondary pump (the one to the plate heat exchanger) is at a greater
head than the primary pump (from the boiler), any heat delivered by the
boiler will go across the top of a flat store and into the pipe opposite
leading to the plate heat exchanger.
If the external pipes are arranged correctly the boilers heat can bypass the
store and go directly to the plate heat exchanger.
> It would also be technically possible with a direct store to arrange
> that the boiler primary water is delivered directly to the secondary
> exchanger directly by rigging up a diverting arrangement of three
> motorised 2 port zone valves. Draw it as two connections onto the
> store with a valve on each and a bridge between the two with a valve
> on that. The boiler connection would go to one junction between
> valves and the heat exchanger on the other. In normal operation the
> valves leading to the store would be open and the bridging one closed,
> putting the store in the circuit. When the store ran out close the
> two valves and open the bridging one, connecting boiler directly to
> heat exchanger. This could be controlled via a thermostat on the
> store and the auxiliary contacts of the valves. It would mean that
> once the store was out, all the boiler energy would go to the heat
> exchanger, giving better performance than if the store is in the
> middle. This creates the functional equivalent of a combi boiler
> with two heat exchangers between the burner and the secondary water
> rather than one. My point here was this is not that interesting if
> you are comparing what the store plus the boiler does compared with
> the boiler alone. The thing should be designed with enough capacity
> that you never run out of store energy.
Andy, you are starting to think a little, this is encouraging in a perverse
way. Your solution is very complex, as the same can be achieved by having
different head settings on two pumps.
You say: "The thing should be designed with enough capacity that you never
run out of store energy.". Not so. You arrange so that all the energy
available to you is used - the heat store and boiler are collectively
harnessed.
> My contention is that when you have a
> continuously available single
> energy source such as gas, from an
> energy perspective you gain little
> vs. a good cylinder arrangement other
> than perhaps a 20% space saving.
Andy, not there on this one. Disappointing again. But keep the thinking up.
> With a condensing boiler, if the store
> is used as part of the space
> heating, the efficiency is going to
> be worse because of the
> temperature required in the store to
> make it worthwhile.
Again you disappoint. A condenser will "overall" have greater efficiencies
on a heat bank, as it operates in a set environment at all times and is
NEVER in an inefficient high temp mode. Having a no-flame boiler on heat
banks, rather than condesning boilers, and great efficiencies are had.
If a CH system is engineered to get the best from a condenser by having
expensive large oversized rads then a condenser will give great efficiencies
and a DHW only heat bank will suffice.
> There are some other practical advantages
> [of heat banks] such as no need for an
> overflow or discharge and that the store can
> be DIY installed. These can be big decision
> influencing issues.
Not arf.
> There are other things that can be done
> with plate heat exchangers
> like putting one on the primary of the
> boiler and then having a HW
> cylinder on the secondary side with a
> potable water pump - e.g. a
> Grundfos bronze one. This would
> transfer energy into the cylinder
> more effectively than a copper coil - even
> a fast recovery one.
Why would you want to that when a heat bank can do that even better all in
one small package.
> I use one very effectively between two
> parts of my heating system to
> separate the house from the workshop
> heating, so I can say that they work well.
Why do you separate them? What is wrong with running the same water in the
IMM
> With a direct store, as long as the boiler connections and the heat
> exchanger connections are both near top and bottom of the store, it
> can be argued to a point that once the store is empty of its own heat
> that stratification would cause a "flow" of hot boiler water across
> the top of the store and cool across the bottom. However, there is
> bound to be some mixing due to pump action because the flow rates
> between boiler and store and store and secondary heat exchanger won't
> be the same. Therefore some energy will go into the store - not all
> to the heat exchanger.
If the secondary pump (the one to the plate heat exchanger) is at a greater
head than the primary pump (from the boiler), any heat delivered by the
boiler will go across the top of a flat store and into the pipe opposite
leading to the plate heat exchanger.
If the external pipes are arranged correctly the boilers heat can bypass the
store and go directly to the plate heat exchanger.
> It would also be technically possible with a direct store to arrange
> that the boiler primary water is delivered directly to the secondary
> exchanger directly by rigging up a diverting arrangement of three
> motorised 2 port zone valves. Draw it as two connections onto the
> store with a valve on each and a bridge between the two with a valve
> on that. The boiler connection would go to one junction between
> valves and the heat exchanger on the other. In normal operation the
> valves leading to the store would be open and the bridging one closed,
> putting the store in the circuit. When the store ran out close the
> two valves and open the bridging one, connecting boiler directly to
> heat exchanger. This could be controlled via a thermostat on the
> store and the auxiliary contacts of the valves. It would mean that
> once the store was out, all the boiler energy would go to the heat
> exchanger, giving better performance than if the store is in the
> middle. This creates the functional equivalent of a combi boiler
> with two heat exchangers between the burner and the secondary water
> rather than one. My point here was this is not that interesting if
> you are comparing what the store plus the boiler does compared with
> the boiler alone. The thing should be designed with enough capacity
> that you never run out of store energy.
Andy, you are starting to think a little, this is encouraging in a perverse
way. Your solution is very complex, as the same can be achieved by having
different head settings on two pumps.
You say: "The thing should be designed with enough capacity that you never
run out of store energy.". Not so. You arrange so that all the energy
available to you is used - the heat store and boiler are collectively
harnessed.
> My contention is that when you have a
> continuously available single
> energy source such as gas, from an
> energy perspective you gain little
> vs. a good cylinder arrangement other
> than perhaps a 20% space saving.
Andy, not there on this one. Disappointing again. But keep the thinking up.
> With a condensing boiler, if the store
> is used as part of the space
> heating, the efficiency is going to
> be worse because of the
> temperature required in the store to
> make it worthwhile.
Again you disappoint. A condenser will "overall" have greater efficiencies
on a heat bank, as it operates in a set environment at all times and is
NEVER in an inefficient high temp mode. Having a no-flame boiler on heat
banks, rather than condesning boilers, and great efficiencies are had.
If a CH system is engineered to get the best from a condenser by having
expensive large oversized rads then a condenser will give great efficiencies
and a DHW only heat bank will suffice.
> There are some other practical advantages
> [of heat banks] such as no need for an
> overflow or discharge and that the store can
> be DIY installed. These can be big decision
> influencing issues.
Not arf.
> There are other things that can be done
> with plate heat exchangers
> like putting one on the primary of the
> boiler and then having a HW
> cylinder on the secondary side with a
> potable water pump - e.g. a
> Grundfos bronze one. This would
> transfer energy into the cylinder
> more effectively than a copper coil - even
> a fast recovery one.
Why would you want to that when a heat bank can do that even better all in
one small package.
> I use one very effectively between two
> parts of my heating system to
> separate the house from the workshop
> heating, so I can say that they work well.
Why do you separate them? What is wrong with running the same water in the
IMM
> With a direct store, as long as the boiler connections and the heat
> exchanger connections are both near top and bottom of the store, it
> can be argued to a point that once the store is empty of its own heat
> that stratification would cause a "flow" of hot boiler water across
> the top of the store and cool across the bottom. However, there is
> bound to be some mixing due to pump action because the flow rates
> between boiler and store and store and secondary heat exchanger won't
> be the same. Therefore some energy will go into the store - not all
> to the heat exchanger.
If the secondary pump (the one to the plate heat exchanger) is at a greater
head than the primary pump (from the boiler), any heat delivered by the
boiler will go across the top of a flat store and into the pipe opposite
leading to the plate heat exchanger.
If the external pipes are arranged correctly the boilers heat can bypass the
store and go directly to the plate heat exchanger.
> It would also be technically possible with a direct store to arrange
> that the boiler primary water is delivered directly to the secondary
> exchanger directly by rigging up a diverting arrangement of three
> motorised 2 port zone valves. Draw it as two connections onto the
> store with a valve on each and a bridge between the two with a valve
> on that. The boiler connection would go to one junction between
> valves and the heat exchanger on the other. In normal operation the
> valves leading to the store would be open and the bridging one closed,
> putting the store in the circuit. When the store ran out close the
> two valves and open the bridging one, connecting boiler directly to
> heat exchanger. This could be controlled via a thermostat on the
> store and the auxiliary contacts of the valves. It would mean that
> once the store was out, all the boiler energy would go to the heat
> exchanger, giving better performance than if the store is in the
> middle. This creates the functional equivalent of a combi boiler
> with two heat exchangers between the burner and the secondary water
> rather than one. My point here was this is not that interesting if
> you are comparing what the store plus the boiler does compared with
> the boiler alone. The thing should be designed with enough capacity
> that you never run out of store energy.
Andy, you are starting to think a little, this is encouraging in a perverse
way. Your solution is very complex, as the same can be achieved by having
different head settings on two pumps.
You say: "The thing should be designed with enough capacity that you never
run out of store energy.". Not so. You arrange so that all the energy
available to you is used - the heat store and boiler are collectively
harnessed.
> My contention is that when you have a
> continuously available single
> energy source such as gas, from an
> energy perspective you gain little
> vs. a good cylinder arrangement other
> than perhaps a 20% space saving.
Andy, not there on this one. Disappointing again. But keep the thinking up.
> With a condensing boiler, if the store
> is used as part of the space
> heating, the efficiency is going to
> be worse because of the
> temperature required in the store to
> make it worthwhile.
Again you disappoint. A condenser will "overall" have greater efficiencies
on a heat bank, as it operates in a set environment at all times and is
NEVER in an inefficient high temp mode. Having a no-flame boiler on heat
banks, rather than condesning boilers, and great efficiencies are had.
If a CH system is engineered to get the best from a condenser by having
expensive large oversized rads then a condenser will give great efficiencies
and a DHW only heat bank will suffice.
> There are some other practical advantages
> [of heat banks] such as no need for an
> overflow or discharge and that the store can
> be DIY installed. These can be big decision
> influencing issues.
Not arf.
> There are other things that can be done
> with plate heat exchangers
> like putting one on the primary of the
> boiler and then having a HW
> cylinder on the secondary side with a
> potable water pump - e.g. a
> Grundfos bronze one. This would
> transfer energy into the cylinder
> more effectively than a copper coil - even
> a fast recovery one.
Why would you want to that when a heat bank can do that even better all in
one small package.
> I use one very effectively between two
> parts of my heating system to
> separate the house from the workshop
> heating, so I can say that they work well.
Why do you separate them? What is wrong with running the same water in the
IMM
> With a direct store, as long as the boiler connections and the heat
> exchanger connections are both near top and bottom of the store, it
> can be argued to a point that once the store is empty of its own heat
> that stratification would cause a "flow" of hot boiler water across
> the top of the store and cool across the bottom. However, there is
> bound to be some mixing due to pump action because the flow rates
> between boiler and store and store and secondary heat exchanger won't
> be the same. Therefore some energy will go into the store - not all
> to the heat exchanger.
If the secondary pump (the one to the plate heat exchanger) is at a greater
head than the primary pump (from the boiler), any heat delivered by the
boiler will go across the top of a flat store and into the pipe opposite
leading to the plate heat exchanger.
If the external pipes are arranged correctly the boilers heat can bypass the
store and go directly to the plate heat exchanger.
> It would also be technically possible with a direct store to arrange
> that the boiler primary water is delivered directly to the secondary
> exchanger directly by rigging up a diverting arrangement of three
> motorised 2 port zone valves. Draw it as two connections onto the
> store with a valve on each and a bridge between the two with a valve
> on that. The boiler connection would go to one junction between
> valves and the heat exchanger on the other. In normal operation the
> valves leading to the store would be open and the bridging one closed,
> putting the store in the circuit. When the store ran out close the
> two valves and open the bridging one, connecting boiler directly to
> heat exchanger. This could be controlled via a thermostat on the
> store and the auxiliary contacts of the valves. It would mean that
> once the store was out, all the boiler energy would go to the heat
> exchanger, giving better performance than if the store is in the
> middle. This creates the functional equivalent of a combi boiler
> with two heat exchangers between the burner and the secondary water
> rather than one. My point here was this is not that interesting if
> you are comparing what the store plus the boiler does compared with
> the boiler alone. The thing should be designed with enough capacity
> that you never run out of store energy.
Andy, you are starting to think a little, this is encouraging in a perverse
way. Your solution is very complex, as the same can be achieved by having
different head settings on two pumps.
You say: "The thing should be designed with enough capacity that you never
run out of store energy.". Not so. You arrange so that all the energy
available to you is used - the heat store and boiler are collectively
harnessed.
> My contention is that when you have a
> continuously available single
> energy source such as gas, from an
> energy perspective you gain little
> vs. a good cylinder arrangement other
> than perhaps a 20% space saving.
Andy, not there on this one. Disappointing again. But keep the thinking up.
> With a condensing boiler, if the store
> is used as part of the space
> heating, the efficiency is going to
> be worse because of the
> temperature required in the store to
> make it worthwhile.
Again you disappoint. A condenser will "overall" have greater efficiencies
on a heat bank, as it operates in a set environment at all times and is
NEVER in an inefficient high temp mode. Having a no-flame boiler on heat
banks, rather than condesning boilers, and great efficiencies are had.
If a CH system is engineered to get the best from a condenser by having
expensive large oversized rads then a condenser will give great efficiencies
and a DHW only heat bank will suffice.
> There are some other practical advantages
> [of heat banks] such as no need for an
> overflow or discharge and that the store can
> be DIY installed. These can be big decision
> influencing issues.
Not arf.
> There are other things that can be done
> with plate heat exchangers
> like putting one on the primary of the
> boiler and then having a HW
> cylinder on the secondary side with a
> potable water pump - e.g. a
> Grundfos bronze one. This would
> transfer energy into the cylinder
> more effectively than a copper coil - even
> a fast recovery one.
Why would you want to that when a heat bank can do that even better all in
one small package.
> I use one very effectively between two
> parts of my heating system to
> separate the house from the workshop
> heating, so I can say that they work well.
Why do you separate them? What is wrong with running the same water in the
Andy Hall
You have missed the point about indirect heat banks where the transfer
from the boiler to the store is via a coil.
>
>That is the difference in the basic operation. Heat banks are more
>efficient, the plate heat exchangers are resistant to scale build up and can
>be easily removed for de-scaling. A heat bank gives far high flow rates
>than a simple thermal store. Thermal stores/heat banks, score over unvented
>cylinders on many points: no high pressure storage, no BBA approved fitting,
>faster recovery, can "combine" the energy of the boiler and the stored hot
>water to give high flow rates,
The whole idea of "combining" is not the sole prerogative of the
heatbank. A conventional cylinder, a thermal store and a heatbank all
do it.
> will "never" run out of hot water if
>configured correctly,
but to no greater extent than any other system if designed correctly.
>no complex high pressure controls, no air pocket to
>maintain in the top of the cylinder, etc, etc.
>
>Both types reduce/eliminate inefficient boiler cycling.
An indirect one may cycle if the boiler is not a modulating type
unless all the heat that it can produce can be transferred by the
coil. Neither are optimally suited for use with condensing boilers if
the CH is being run from the store/bank.
> Both types can also
>be DHW only or "integrated" supplying DHW and CH. The CH is supplied by
>taking flow and return pipes off the bottom of the store.
Which is not appropriate with condensing boilers.
>
>Both types can have electric immersion backup for DHW and CH, depending on
>the immersion size of course.
>
>The beauty of a heat bank is that with a little imagination the energy of
>the boiler and the energy of the stored water can be "combined" to instantly
>heat cold mains water (the view is: if the power is there in the boiler then
>use it, don't let it sit there just topping up a water store).
...And exactly the same happens with a conventional cylinder.
> This reduces
>the size of the store required, with the 80 litre DPS GXV it can fit under a
>kitchen worktop, supply 170 litres of 45C water at 25 litres/minutes flow
>rate, using a 40-50,000 Btus directly connected boiler. Very impressive.
until you read the entire article and realise that they have left out
the flow figures for when the store has run out. They also leave out
the mains cold temperature which makes all of these figures utterly
meaningless anyway.
>You will ,never run out of hot water, although the flow will reduce when the
>heat bank runs out of hot water).
Like the side of a house. Down to something like 11 litres/min for
this size of boiler.
You neglected to make the point that a direct heatbank will require a
boiler able to work on an open vented system, which restricts choice.
It's interesting to note that most of the products on the DPS web site
are indirect......
>
>Being direct (the boiler and heat bank use the same water) any sized boiler
>can be fitted to the heat bank. If you uprate the boiler to 100,000 Btus
>the DHW performance is even better (a domestic gas supply can give 212 cu
>ft/hr, so you can use two cheap boilers giving 190,000 Btus (190 cu ft/hr),
>with staggering DHW performance and boiler backup too just using a 80 litre
>heat bank. That is if you want to pay the extra for the performance and the
>boiler backup. When no DHW is being drawn off then the boiler replenished
>the store.
>
>This type of "combined" boiler/stored water heat bank can be sized up, so
>that a smallish boiler can be fitted and most of the energy used to heat DHW
>is via the water heat store, or you can downsize the store to fit into a
>small space and use a powerful boiler, which don't take up much more space
>than smallish boiler. Or if you want real instant staggering performance,
>as I previously mentioned, use two cheap boilers, which will give backup if
>one is down, and just the boilers alone will give around 20-22 litres DHW if
>the heat banks energy is exhausted.
>
>
One could also choose different sizes of standard HW cylinder, and
given a large, well insulated one could have a system that outperforms
any of this.
IMM
Andy Hall
>>
>> If this were such a good idea,
>> large numbers of installations as you
>> describe would be done.
>
>The industry is locked into set ways. Why do they put boilers in kitchens,
>taking up cupboard space, when the loft is empty?
>
Hardly a fair comparison, but the answer in both cases is economic.
>> All that you have described is a feature of a heat store.
>> An equivalent effect can be achieved from a HW storage cylinder
>> of 20% greater volume.
>
>Read all this thread agian - 4 times.
It doesn't change the facts.
>
>> >I pointed you to the DPS site. Read it as
>> >most is in there except the mode
>> >switching of combined and replenished.
>>
>> There is some useful information on that site. However since the
>> product specifications are not completely laid out and pieces are
>> missing from the test example that they give, further checking would
>> be needed to decide whether the results are as good as implied.
>> I don't see any examples of huge boiler capacity and tiny stores.
>
>Anyone who knows about HVAC can see that larger output, snallish cased
>cheapish boilers can be mated to these heat banks, lowering the size. In
>fact the GXV was designed with small storage in mind, to fit into small
>British houses. With the direct version, there is no limitation on boiler
>size. Not being inthe business and poor at grasping concepts, You obviously
>can't see this.
I can see it perfectly well, but it's pointless. If you have a house
of the size where this product makes sense in terms of capacity, you
might as well install a combi and save even more space. The storage
is too small to be interesting.
>
>Go to DPS and say: Sir, I want one of your 80 litre GXV heat banks and want
>to put two 80,000 Btus boioers on it, can you install the correct sized
>tapping for me. They will say: Yes Sir, it will work superbly and we will
>install the correct sized tappings for the boilers.
I am sure they could, but it's highly unlikely that I would ever do
it. since they don't provide complete specifications for the product
and leave out the awkward bits.
>
>> >> Just an honours degree in engineering
>> >> and a successful career.
>> >
>> >In computer networks!!!!!!!
>>
>> ... and RF design, microprocessor control system implementation, power
>> electronics, semiconductor applications, audio system automation,
>> operating systems, databases, applications, network design and
>> implementation, video technology, support and services, marketing,
>
>I see NO HVAC.
Absolutely. However, I haven't claimed a professional qualification
in the field as you have. What it does illustrate is an ability to
cover a multitude of areas and be successful in each. This requires
being able to appreciate and understand what is happening - the
important factors - and to then be able to obtain and verify specific
information as required.
>Operating systems. What operating system have you
>fdesigned/implemeted? Don't porkie tell!!!!!
I didn't claim to have implemented an operating system, if you read
what I wrote, although I did design and produce a real-time kernel for
a control system for one project because of the absence of anything
off the shelf at the time.
>
>> >No modern applications engineer
>> >goes back to basic physics. It is all
>> >boilerplate.
>>
>> It's always good practice to do a
>> basic principles sanity check.
>> This avoids costly mistakes.
>
>They go from boiler plate, which is tables, graphs, etc, I repeat: No modern
>applications engineer goes back to basic physics. It is all boilerplate".
>No one has the time to piss around proving the proven boiler plate wrong.
>That is the stuff they do at college.
>
I didn't say that an engineer goes back to first principles each time
- that has never been the case. Boilerplates are useful for the
majority of cases - the question is whether an engineer knows what to
do for the cases where the requirement is outside the boilerplate.
This is only an application of the 80/20 rule. If you have boiler
plates that can cover 80% of the cases, you can de-skill these to
technician level. The engineer will do the more difficult jobs and
apply sanity checks to the technician's designs.
From my contacts in the HVAC industry, I know that this is how it is
done in professional firms.
>> >> I sent one a copy of one of your
>> >> threads recently and we had quite a
>> >> good laugh about it. "Which planet
>> >> is he on?" was one comment.
>> >
>> >He is obviously on yours, wherever that is.
>>
>> Seemingly the one that the rest of us are on.
>
>Tell your confused engineer to ask Qs on here and I will put him right.
>
I couldn't do that to you. He doesn't suffer fools and would eat you
for breakfast.
IMM
"Andy Hall" <an...@hall.nospam> wrote in message
This is an overview. You can also have pressurised heat banks where the
whole cylinder is under pressure with the boiler.
> >That is the difference in the basic operation. Heat banks are more
> >efficient, the plate heat exchangers are resistant to scale build up and
can
> >be easily removed for de-scaling. A heat bank gives far high flow rates
> >than a simple thermal store. Thermal stores/heat banks, score over
unvented
> >cylinders on many points: no high pressure storage, no BBA approved
fitting,
> >faster recovery, can "combine" the energy of the boiler and the stored
hot
> >water to give high flow rates,
>
> The whole idea of "combining" is not
> the sole prerogative of the
> heatbank. A conventional cylinder, a
> thermal store and a heatbank all
> do it.
Once again you disappoint. They do not. They do not put the peak of their
power to the point of heat transfer.
>
> > will "never" run out of hot water if
> >configured correctly,
>
> but to no greater extent than any
> other system if designed correctly.
Not so. Once again you disappoint.
> >no complex high pressure controls, no air pocket to
> >maintain in the top of the cylinder, etc, etc.
> >
> >Both types reduce/eliminate inefficient boiler cycling.
>
> An indirect one may cycle if the
> boiler is not a modulating type
> unless all the heat that it can produce
> can be transferred by the
> coil.
This is so. But once again you disappoint. You size boiler and coil to
suit.
> > Both types can also
> >be DHW only or "integrated" supplying DHW and CH. The CH is supplied by
> >taking flow and return pipes off the bottom of the store.
>
> Which is not appropriate with condensing boilers.
Once again you disappoint. Condenser are appropriate. the DPS test was
using a condensing boiler.
> >The beauty of a heat bank is that with a little imagination the energy of
> >the boiler and the energy of the stored water can be "combined" to
instantly
> >heat cold mains water (the view is: if the power is there in the boiler
then
> >use it, don't let it sit there just topping up a water store).
>
> ...And exactly the same happens with a conventional cylinder.
Once again you disappoint. Not so, or with great difficulty, complexity and
expense.
> > This reduces
> >the size of the store required, with the 80 litre DPS GXV it can fit
under a
> >kitchen worktop, supply 170 litres of 45C water at 25 litres/minutes flow
> >rate, using a 40-50,000 Btus directly connected boiler. Very impressive.
>
> until you read the entire article and realise that they have left out
> the flow figures for when the store has run out.
Once again you disappoint. This will be what the boiler can provide.
Ballpark: 90,000 Btus gives 10-11 litres/min.
> They also leave out
> the mains cold temperature which
> makes all of these figures utterly
> meaningless anyway.
They stated 12C
> >You will ,never run out of hot water,
> >although the flow will reduce when the
> >heat bank runs out of hot water).
>
> Like the side of a house.
???
> Down to something like 11 litres/min for
> this size of boiler.
You are getting it.
> You neglected to make the point
> that a direct heatbank will require a
> boiler able to work on an open vented
> system, which restricts choice.
Not so much at all. Foire e.g, most Baxi, Glow Worm, etc are pressurised or
open vented.
Once again you disappoint. The cylinders will have to be very large indeed.
IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> >> If this were such a good idea,
> >> large numbers of installations as you
> >> describe would be done.
> >
> >The industry is locked into set ways.
> >Why do they put boilers in kitchens,
> >taking up cupboard space, when the loft is empty?
>
> Hardly a fair comparison,
Once again you disappoint. It is.
> but the answer in both cases is economic.
Once again you disappoint. It is not.
> >> All that you have described is a feature of a heat store.
> >> An equivalent effect can be achieved from a HW storage cylinder
> >> of 20% greater volume.
> >
> >Read all this thread agian - 4 times.
>
> It doesn't change the facts.
Once again you disappoint. It may sink in though.
> >> >I pointed you to the DPS site. Read it as
> >> >most is in there except the mode
> >> >switching of combined and replenished.
> >>
> >> There is some useful information on that site. However since the
> >> product specifications are not completely laid out and pieces are
> >> missing from the test example that they give, further checking would
> >> be needed to decide whether the results are as good as implied.
> >> I don't see any examples of huge boiler capacity and tiny stores.
> >
> >Anyone who knows about HVAC can see that larger output, snallish cased
> >cheapish boilers can be mated to these heat banks, lowering the size. In
> >fact the GXV was designed with small storage in mind, to fit into small
> >British houses. With the direct version, there is no limitation on
boiler
> >size. Not being inthe business and poor at grasping concepts, You
obviously
> >can't see this.
>
> I can see it perfectly well,
Once again you disappoint. You can't see perfectly well.
> >Go to DPS and say: Sir, I want one of your 80 litre GXV heat banks and
want
> >to put two 80,000 Btus boioers on it, can you install the correct sized
> >tapping for me. They will say: Yes Sir, it will work superbly and we
will
> >install the correct sized tappings for the boilers.
>
> I am sure they could, but it's highly unlikely that I would ever do
> it. since they don't provide complete specifications for the product
> and leave out the awkward bits.
Once again you disappoint. You must contact them direct. They one on
display for customer to measure if they want to.
> >> >> Just an honours degree in engineering
> >> >> and a successful career.
> >> >
> >> >In computer networks!!!!!!!
> >>
> >> ... and RF design, microprocessor control system implementation, power
> >> electronics, semiconductor applications, audio system automation,
> >> operating systems, databases, applications, network design and
> >> implementation, video technology, support and services, marketing,
> >
> >I see NO HVAC.
>
> Absolutely.
Game, set and match!
> >Operating systems. What operating system have you
> >designed/implemeted? Don't porkie tell!!!!!
>
> I didn't claim to have implemented
> an operating system, if you read
> what I wrote, although I did design
> and produce a real-time kernel for
> a control system for one project
> because of the absence of anything
> off the shelf at the time.
That is not an OS. that is writing an app that can be compiled as part of
the kernel. Once again you disappoint.
> >> >No modern applications engineer
> >> >goes back to basic physics. It is all
> >> >boilerplate.
> >>
> >> It's always good practice to do a
> >> basic principles sanity check.
> >> This avoids costly mistakes.
> >
> >They go from boiler plate, which is tables, graphs, etc, I repeat: No
modern
> >applications engineer goes back to basic physics. It is all
boilerplate".
> >No one has the time to piss around proving the proven boiler plate wrong.
> >That is the stuff they do at college.
>
> I didn't say that an engineer
> goes back to first principles each time
Once again you disappoint. You did.
> >Tell your confused engineer to ask
> >Qs on here and I will put him right.
>
> I couldn't do that to you. He doesn't
> suffer fools
Neither do I.
> and would eat you
> for breakfast.
Try me.
Andy Hall
>
>"Andy Hall" <an...@hall.nospam> wrote in message
>news:ghi8bv0frl42nruu1...@4ax.com...
>
>> With a direct store, as long as the boiler connections and the heat
>> exchanger connections are both near top and bottom of the store, it
>> can be argued to a point that once the store is empty of its own heat
>> that stratification would cause a "flow" of hot boiler water across
>> the top of the store and cool across the bottom. However, there is
>> bound to be some mixing due to pump action because the flow rates
>> between boiler and store and store and secondary heat exchanger won't
>> be the same. Therefore some energy will go into the store - not all
>> to the heat exchanger.
>
>If the secondary pump (the one to the plate heat exchanger) is at a geater
>head than the primary pump (from the boiler), any heat delivered by the
>boiler will go across the top of a flat store and into the pipe opposite
>leading to the plate heat exchanger.
If the head of the secondary is higher, the hot water coming from the
boiler will mix with cooler water from the store. The effect of this
will be to reduce the rate of heat transfer and to warm the store.
Even if the two flow rates were matched perfectly, which would never
happen in practice, other effects such as turbulence from the flow in
and out will cause a stirring and mixing of the store water.
>
>If the external pipes are arranged correctly the boilers heat can bypass the
>store and go directly to the plate heat exchanger.
>
>> It would also be technically possible with a direct store to arrange
>> that the boiler primary water is delivered directly to the secondary
>> exchanger directly by rigging up a diverting arrangement of three
>> motorised 2 port zone valves. Draw it as two connections onto the
>> store with a valve on each and a bridge between the two with a valve
>> on that. The boiler connection would go to one junction between
>> valves and the heat exchanger on the other. In normal operation the
>> valves leading to the store would be open and the bridging one closed,
>> putting the store in the circuit. When the store ran out close the
>> two valves and open the bridging one, connecting boiler directly to
>> heat exchanger. This could be controlled via a thermostat on the
>> store and the auxiliary contacts of the valves. It would mean that
>> once the store was out, all the boiler energy would go to the heat
>> exchanger, giving better performance than if the store is in the
>> middle. This creates the functional equivalent of a combi boiler
>> with two heat exchangers between the burner and the secondary water
>> rather than one. My point here was this is not that interesting if
>> you are comparing what the store plus the boiler does compared with
>> the boiler alone. The thing should be designed with enough capacity
>> that you never run out of store energy.
>
>Andy, you are starting to think a little, this is encouraging in a strange
>way.
Thank you for your endorsement.
>Your solution is very complex, as the same cane be achieved by having
>different head settings on two pumps.
Mine would guarantee that *all* the heat went to the plate heat
exchanger, whereas titting around with pumps will only go so far.
However, I did go on to say that it is a pointless exercise since it
just recreates a kind of two stage combi.
>
>You say: "The thing should be designed with enough capacity that you never
>run out of store energy.". Not so. You arrange so that all the energy
>available to you is used - the heat store and boiler together.
Yes, OK. If I state it a different way, The store energy plus that
added by the boiler as the store depletes need to be enough, together
so that the store doesn't run out. That is if you consider, as I do,
that running with boiler energy only doesn't provide enough
performance. If you are prepared to accept a degradation of
performance when the store runs out, that's another matter/.
>
>> My contention is that when you have a
>> continuously available single
>> energy source such as gas, from an
>> energy perspective you gain little
>> vs. a good cylinder arrangement other
>> than perhaps a 20% space saving.
>
>Andy, not there on this one. Disappointing again. But keep the thinking up.
>
>> With a condensing boiler, if the store
>> is used as part of the space
>> heating, the efficiency is going to
>> be worse because of the
>> temperature required in the store to
>> make it worthwhile.
>
>Again you disappoint. A condenser will "overall" have greater efficiencies
>on a heat bank, as it operates in a set environment at all times.
Sorry I don't buy that. The efficiency graphs for condensing boilers
show that the lower the temperature the better the efficiency, not
running at a constant rate. The modulating behaviour of the burner
allows the boiler to keep running rather than going on and off. We
know that boiler cycling on any type of boiler reduces efficiency.
>Having a
>no-flame boiler on heat banks and great efficiencies are had.
On paper that would appear to be the case.
>
>If a CH system is engineered to get the best from a condenser by having
>expensive large oversized rads then a condenser will give great efficiencies
>and a DHW only heat bank will suffice.
Which was one of my main points - don't run the CH from the heat bank
where a condensing boiler is in use.
It isn't necessarily true to say that radiators have to be hugely
larger. I did the calculations for my system and found that some of
the radiators were oversized for 82/70 running anyway but were just
right for 70/50. I took off and threw away the smallest of the
remainder and resited some of the larger ones to smaller rooms.
I bought three new double panel finned radiators which had the same
size on the wall as previous radiators.
>
>> There are some other practical advantages
>> [of heat banks] such as no need for an
>> overflow or discharge and that the store can
>> be DIY installed. These can be big decision
>> influencing issues.
>
>Not arf.
>
>> There are other things that can be done
>> with plate heat exchangers
>> like putting one on the primary of the
>> boiler and then having a HW
>> cylinder on the secondary side with a
>> potable water pump - e.g. a
>> Grundfos bronze one. This would
>> transfer energy into the cylinder
>> more effectively than a copper coil - even
>> a fast recovery one.
>
>Why would you want to that when a heat bank can do that even better all in
>one small package.
DPS seemed to think it was a good idea for one of their customers.
They called it a "store" but really it is just replacing the coil heat
exchanger in the cylinder with a plate one. Not a bad idea. I'm
surprised that they don't make a heatbank with two plate exchangers
rather than a coil and a plate.
>
>> I use one very effectively between two
>> parts of my heating system to
>> separate the house from the workshop
>> heating, so I can say that they work well.
>
>Why do you separate them? What is wrong with running the same water in the
>workshop and the house. Simpler and cheaper too.
>
I did consider that, but decided to separate the two for two main
reasons.
The workshop is a separate building from the house and the (insulated)
pipes run in an insulated underground duct. There is a controller in
the workshop with night setback and frost protection, but in the event
of power failure for a long period there could be a higher risk of
freezing. I dealt with that by using an inhibitor with antifreeze
for the workshop, but it is quite expensive and to fill the entire
system including the house would cost the same as a plate heat
exchanger.
The second issue is the control arrangement. The workshop has its
own (Alpha) pump which is operated by the thermostat. In the house
there is a flow switch on the workshop circuit near the heat exchanger
which opens a motorised 2 port zone valve when water flows (i.e.
demand from workshop zone.) This in turn fires up the boiler in CH
mode unless overridden by DHW demand. This neatly avoids the issue of
running wiring for control between house and workshop which is a
separate equipotential earthing zone.
The only additional components required vs. running as one circuit
were a pump (which I had anyway), a flow switch, the heat exchanger
and a sealed system kit - outlay just over £100. Not far different
from the extra inhibitor cost. Plus, if anything bad happens in the
workshop or in between, there is no compromise to the house system.
Because the heat exchanger is oversized for the purpose (I really only
need about 6kW worst case), there is little temperature drop and the
workshop radiators only run a degree or two cooler than the house
ones.
There is a separate pump
IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> >If the secondary pump (the one to the
> >plate heat exchanger) is at a geater
> >head than the primary pump (from the
> >boiler), any heat delivered by the
> >boiler will go across the top of a flat
> >store and into the pipe opposite
> >leading to the plate heat exchanger.
>
> If the head of the secondary is higher,
> the hot water coming from the
> boiler will mix with cooler water from
> the store. The effect of this
> will be to reduce the rate of heat
> transfer and to warm the store.
You have the secondary just higher than the primary.
But there is a better way.
> Yes, OK. If I state it a different way,
> The store energy plus that
> added by the boiler as the store depletes
> need to be enough, together
> so that the store doesn't run out. That
> is if you consider, as I do, that running
> with boiler energy only doesn't provide enough
> performance. If you are prepared to
> accept a degradation of performance when
> the store runs out, that's another matter/.
Once again you disappoint. You size to suit, but you if you do run out of
stored energy the boiler will produce it instantly.
You size the system so that the store compliments the boilers output. Use
what the boiler has to offer, don't allow it to sit there just topping up
hot water.
> >Again you disappoint. A condenser will
> >"overall" have greater efficiencies
> >on a heat bank, as it operates in a set
> >environment at all times.
>
> Sorry I don't buy that.
Once again you disappoint. You will have to just accept that point.
> >Having a no-flame boiler on
> >heat banks and great efficiencies are had.
>
> On paper that would appear to be the case.
Encouraging!
> >If a CH system is engineered to get the
> >best from a condenser by having
> >expensive large oversized rads then
> >a condenser will give great efficiencies
> >and a DHW only heat bank will suffice.
>
> Which was one of my main points - don't
> run the CH from the heat bank
> where a condensing boiler is in use.
If you want large ugly oversized rads then do it. Also if you are using
Myson convector heaters then you have it on 80C. Load compensation
condensers are out in this case.
> >> There are other things that can be done
> >> with plate heat exchangers
> >> like putting one on the primary of the
> >> boiler and then having a HW
> >> cylinder on the secondary side with a
> >> potable water pump - e.g. a
> >> Grundfos bronze one. This would
> >> transfer energy into the cylinder
> >> more effectively than a copper coil - even
> >> a fast recovery one.
> >
> >Why would you want to that when
> >a heat bank can do that even better all in
> >one small package.
>
> DPS seemed to think it was a
> good idea for one of their customers.
Probably has an existing very large direct cylinder and this is a cost
effective way of getting around a problem.
IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> DPS seemed to think it was a good idea for one of their customers.
> They called it a "store" but really it is just replacing the coil heat
> exchanger in the cylinder with a plate one. Not a bad idea. I'm
> surprised that they don't make a heatbank with two plate exchangers
> rather than a coil and a plate.
I'm sure they will make one to order.
Andy Hall
>
>>
>> You have missed the point about indirect heat banks where the transfer
>> from the boiler to the store is via a coil.
>
>This is an overview. You can also have pressurised heat banks where the
>whole cylinder is under pressure with the boiler.
Which presumably then is a professional install.......
>
>>
>> The whole idea of "combining" is not
>> the sole prerogative of the
>> heatbank. A conventional cylinder, a
>> thermal store and a heatbank all
>> do it.
>
>Once again you disappoint. They do not. They do not put the peak of their
>power to the point of heat transfer.
Please explain the precise mechanism by which they "put the peak of
their power to the point of heat transfer."
This sounds like more waffle.
>>
>> > will "never" run out of hot water if
>> >configured correctly,
>>
>> but to no greater extent than any
>> other system if designed correctly.
>
>Not so. Once again you disappoint.
Don't be ridiculous.
Of course you can design a conventional system which will supply a
high flow rate and with energy being added back by the boiler while
the taps are running. In both cases the addition of boiler energy
extends the running time before the stored energy runs out.
>
>> >no complex high pressure controls, no air pocket to
>> >maintain in the top of the cylinder, etc, etc.
>> >
>> >Both types reduce/eliminate inefficient boiler cycling.
>>
>> An indirect one may cycle if the
>> boiler is not a modulating type
>> unless all the heat that it can produce
>> can be transferred by the
>> coil.
>
>This is so. But once again you disappoint. You size boiler and coil to
>suit.
Obviously.
>
>> > Both types can also
>> >be DHW only or "integrated" supplying DHW and CH. The CH is supplied by
>> >taking flow and return pipes off the bottom of the store.
>>
>> Which is not appropriate with condensing boilers.
>
>Once again you disappoint. Condenser are appropriate. the DPS test was
>using a condensing boiler.
.. and that's your reference? They don't state most of the flow
rates and the temperature of the incoming water and you treat the
results as authoritative?
In any case this has not been my point. That has been that using a
condensing boiler with a heatbank *and* having the heatbank operating
the CH is a poor match - a demonstrable point. If you have the
condensing boiler driving a heatbank only for DHW, I have not said
that that would be more or less efficient than a conventional 82/70
boiler since the condensing boiler would be run at high temperature
with a conventional cylinder as well - not at optimal efficiency.
It's this point that means that there is relatively little difference
if any between a heatbank and a conventional cylinder if used for DHW
only from the energy and performance point of view. If the heatbank is
indirect through a coil then the only issue can be the size
>
>> >The beauty of a heat bank is that with a little imagination the energy of
>> >the boiler and the energy of the stored water can be "combined" to
>instantly
>> >heat cold mains water (the view is: if the power is there in the boiler
>then
>> >use it, don't let it sit there just topping up a water store).
>>
>> ...And exactly the same happens with a conventional cylinder.
>
>Once again you disappoint. Not so, or with great difficulty, complexity and
>expense.
Case A. Conventional cylinder of 125 litres
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Boiler heats water through fast recovery coil to 60 degrees at full
boiler rate (e.g. 25kW)
Tap is turned on and water used from hot tap at rate equivalent to
50kW
Boiler replenishes energy at 25kW rate while this is happening.
Net rate of heat loss is 25kW
Case B. Heat bank of 100 litres
~~~~~~~~~~~~~~~~~~~~~~
Boiler heats water through coil or directly to 75 degrees at full 25kW
rate
Tap is turned on and water is heated via plate heat exchanger and
mixed with cold such that the effective usage rate is 50kW.
Boiler replenishes at 25kW while this is happening.
Net rate of heat loss is 25kW.
Both systems will run out of stored energy at the same time because
the energy stored in 125 litres at 60 degrees is the same as in 100
litres at 75 degrees.
Both systems use energy from the boiler to supplement what is being
taken from the store of energy.
From an energy perspective, the results are the same. All that
differs is the size of the cylinder.
>
>> > This reduces
>> >the size of the store required, with the 80 litre DPS GXV it can fit
>under a
>> >kitchen worktop, supply 170 litres of 45C water at 25 litres/minutes flow
>> >rate, using a 40-50,000 Btus directly connected boiler. Very impressive.
>>
>> until you read the entire article and realise that they have left out
>> the flow figures for when the store has run out.
>
>Once again you disappoint. This will be what the boiler can provide.
>Ballpark: 90,000 Btus gives 10-11 litres/min.
Exactly, and that figure is embarassing. For the boiler in question,
the max heat output is 17kW - approx 2/3 of your figure or about 7-8
litres/min.
... and you're trying to suggest that this is an impressive solution?
It's a joke. At the end of the day, you can't get quart out of a
pint pot and this is what is being claimed.
>
>> They also leave out
>> the mains cold temperature which
>> makes all of these figures utterly
>> meaningless anyway.
>
>They stated 12C
No they don't. You're making it up as you go along.
http://www.heatweb.com/products/cylinders/gxv/gxv.htm
which is where the test is described makes no mention of 12 degrees.
>
>> >You will ,never run out of hot water,
>> >although the flow will reduce when the
>> >heat bank runs out of hot water).
>>
>> Like the side of a house.
>
>???
from 25 litres per minute to 8 on a good day.
>> >
>>
>> One could also choose different sizes
>> of standard HW cylinder, and given a large,
>> well insulated one could have a system that outperforms
>> any of this.
>
>Once again you disappoint. The cylinders will have to be very large indeed.
>
>
Precisely 20% larger to achieve the same results as a heatbank.
Andy Hall
>
>"Andy Hall" <an...@hall.nospam> wrote in message
>news:icv9bv4353lq9gk63...@4ax.com...
>
>> >> If this were such a good idea,
>> >> large numbers of installations as you
>> >> describe would be done.
>> >
>> >The industry is locked into set ways.
>> >Why do they put boilers in kitchens,
>> >taking up cupboard space, when the loft is empty?
>>
>> Hardly a fair comparison,
>
>Once again you disappoint. It is.
Running the gas supply up there; two boilers instead of one??
>
>> but the answer in both cases is economic.
>
>Once again you disappoint. It is not.
Two cheap boilers cost the same as one cheap boiler? Gas pipework
is free?
>
>> >Go to DPS and say: Sir, I want one of your 80 litre GXV heat banks and
>want
>> >to put two 80,000 Btus boioers on it, can you install the correct sized
>> >tapping for me. They will say: Yes Sir, it will work superbly and we
>will
>> >install the correct sized tappings for the boilers.
>>
>> I am sure they could, but it's highly unlikely that I would ever do
>> it. since they don't provide complete specifications for the product
>> and leave out the awkward bits.
>
>Once again you disappoint. You must contact them direct. They one on
>display for customer to measure if they want to.
WHy would I want to bother with that? If the product was so good
(which one can work out that it's not) they would publish all of the
figures.
>
>> >> >> Just an honours degree in engineering
>> >> >> and a successful career.
>> >> >
>> >> >In computer networks!!!!!!!
>> >>
>> >> ... and RF design, microprocessor control system implementation, power
>> >> electronics, semiconductor applications, audio system automation,
>> >> operating systems, databases, applications, network design and
>> >> implementation, video technology, support and services, marketing,
>> >
>> >I see NO HVAC.
>>
>> Absolutely.
>
>Game, set and match!
Not really, since I have not claimed to have been professionally
involved in HVAC. The above, as you know full well was to illustrate
an ability to adapt across a range of engineering areas with little
difficulty. The HVAC subject matter here is trivial in relation to
any of the above.
>
>> >Operating systems. What operating system have you
>> >designed/implemeted? Don't porkie tell!!!!!
>>
>> I didn't claim to have implemented
>> an operating system, if you read
>> what I wrote, although I did design
>> and produce a real-time kernel for
>> a control system for one project
>> because of the absence of anything
>> off the shelf at the time.
>
>That is not an OS. that is writing an app that can be compiled as part of
>the kernel. Once again you disappoint.
You have no idea of what you are talking about, so I am not even going
to enter into a discussion on it with you.
IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> >> There are other things that can be done
> >> with plate heat exchangers
> >> like putting one on the primary of the
> >> boiler and then having a HW
> >> cylinder on the secondary side with a
> >> potable water pump - e.g. a
> >> Grundfos bronze one. This would
> >> transfer energy into the cylinder
> >> more effectively than a copper coil - even
> >> a fast recovery one.
> >
> >Why would you want to that when a heat bank can do that even better all
in
> >one small package.
>
> DPS seemed to think it was a good idea for one of their customers.
> They called it a "store" but really it is just replacing the coil heat
> exchanger in the cylinder with a plate one. Not a bad idea. I'm
> surprised that they don't make a heatbank with two plate exchangers
> rather than a coil and a plate.
I looked at that. Poor mains flow and pressure and restricted in cupboard
size. All the boilers energy is directed to the top of the cylinder where
it is being draw-off. This cannot happen with a quick recovery coil as
they tend to lay low down. The blending valve is ensuring only 60C water
goes to the top of the cylinder. This in effect extends the size of the
cylinder (making it smaller, as in the GXV heat bank). The bigger the
boiler the smaller the cylinder can be. Good solution for the given
problem.
Andy Hall
>
>>
>> If the head of the secondary is higher,
>> the hot water coming from the
>> boiler will mix with cooler water from
>> the store. The effect of this
>> will be to reduce the rate of heat
>> transfer and to warm the store.
>
>You have the secondary just higher than the primary.
There will still be mixing in the store.
>
>> Yes, OK. If I state it a different way,
>> The store energy plus that
>> added by the boiler as the store depletes
>> need to be enough, together
>> so that the store doesn't run out. That
>> is if you consider, as I do, that running
>> with boiler energy only doesn't provide enough
>> performance. If you are prepared to
>> accept a degradation of performance when
>> the store runs out, that's another matter/.
>
>Once again you disappoint. You size to suit, but you if you do run out of
>stored energy the boiler will produce it instantly.
At a lower rate. I already said that I discount that situation
because there is a degradation of performance. If others are happy
with it then fine.
>
>You size the system so that the store compliments the boilers output.
Store: "Oh boiler, you are brilliant at producing output!"
>Use
>what the boiler has to offer, don't allow it to sit there just topping up
>hot water.
????
The end result at the tap is the same.
>
>> >Again you disappoint. A condenser will
>> >"overall" have greater efficiencies
>> >on a heat bank, as it operates in a set
>> >environment at all times.
>>
>> Sorry I don't buy that.
>
>Once again you disappoint. You will have to just accept that point.
Yeah, right!.
>
>> >Having a no-flame boiler on
>> >heat banks and great efficiencies are had.
>>
>> On paper that would appear to be the case.
>
>Encouraging!
Assuming that the vendor is telling the truth of course.
>
>> >If a CH system is engineered to get the
>> >best from a condenser by having
>> >expensive large oversized rads then
>> >a condenser will give great efficiencies
>> >and a DHW only heat bank will suffice.
>>
>> Which was one of my main points - don't
>> run the CH from the heat bank
>> where a condensing boiler is in use.
>
>If you want large ugly oversized rads then do it.
I already said that they are not. That can be verified in
manufacturer data.
>Also if you are using
>Myson convector heaters then you have it on 80C.
Noise?
>Load compensation
>condensers are out in this case.
>>
>> DPS seemed to think it was a
>> good idea for one of their customers.
>
>Probably has an existing very large direct cylinder and this is a cost
>effective way of getting around a problem.
>
The problem was providing a large volume of hot water, nothing more
than that.
IMM
> >> You have missed the point about indirect
> >> heat banks where the transfer
> >> from the boiler to the store is via a coil.
> >
> >This is an overview. You can also have
> >pressurised heat banks where the
> >whole cylinder is under pressure with the boiler.
>
> Which presumably then is a professional install.......
BBA. Yes. But the same expansion vessel used for CH can be used. Once
again pressure blow-off equipment has to be used. This has to be
"approved", unvented heat banks do not, so quick custom jobs can be made.
> >This is so. But once again you disappoint.
> >You size boiler and coil to suit.
>
> Obviously.
Then why mention it then?
> In any case this has not been my point.
> That has been that using a
> condensing boiler with a heatbank *and*
> having the heatbank operating
> the CH is a poor match - a demonstrable point.
Not so.
> If you have the condensing boiler driving
> a heatbank only for DHW, I have not said
> that that would be more or less efficient
> than a conventional 82/70 boiler since the
> condensing boiler would be run at high temperature
Not so. Heat banks can be run at 75C giving goog boiler efficiencies.
> Case A. Conventional cylinder of 125 litres
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Boiler heats water through fast recovery coil to 60 degrees at full
> boiler rate (e.g. 25kW)
> Tap is turned on and water used from hot tap at rate equivalent to
> 50kW
> Boiler replenishes energy at 25kW rate while this is happening.
> Net rate of heat loss is 25kW
Poor example. If the store is exausted then there will be only cold water.
Witha heat bank, the fallback is what the boiler will give you, which is
determined by the size of the boiler.
> Case B. Heat bank of 100 litres
> ~~~~~~~~~~~~~~~~~~~~~~
>
> Boiler heats water through coil or directly
> to 75 degrees at full 25kW rate
> Tap is turned on and water is heated via
> plate heat exchanger and
> mixed with cold such that the effective usage rate is 50kW.
> Boiler replenishes at 25kW while this is happening.
> Net rate of heat loss is 25kW.
>
> Both systems will run out of stored energy
> at the same time because the energy stored
> in 125 litres at 60 degrees is the same as in 100
> litres at 75 degrees.
But the heat bank will keep supplying hot water at a reduced rate and have
less stored heat losses.
> Both systems use energy from the boiler
> to supplement what is being
> taken from the store of energy.
Very good observation. BUT the difference is that the heat bank has a
fallback flowrate of what the boiler can supply. Two cheap boilers can
(great for backup) can give 20-22 litres alone. The heat bank can be
downsized to fit in small spaces in small British homes.
> From an energy perspective, the results
> are the same.
Not so, more standing heat losses with a larger cylinder.
> >> > This reduces the size of the store required,
> >> > with the 80 litre DPS GXV it can fit under a
> >> >kitchen worktop, supply 170 litres of 45C
> >> >water at 25 litres/minutes flow rate, using a
> >> >40-50,000 Btus directly connected boiler.
> >> >Very impressive.
> >>
> >> until you read the entire article and
> >> realise that they have left out
> >> the flow figures for when the store has run out.
> >
> >Once again you disappoint. This will be
> > what the boiler can provide.
> >Ballpark: 90,000 Btus gives 10-11 litres/min.
>
> Exactly, and that figure is embarassing.
It is as it about 12 l.min.
> for the boiler in question,
> the max heat output is 17kW -
> approx 2/3 of your figure or about 7-8
> litres/min.
Enough to fill a sink or even have a shower, until replenishment. Great!
> ... and you're trying to suggest that
> this is an impressive solution?
Of course. A small cylinder that goes under a worktop.
> >> They also leave out
> >> the mains cold temperature which
> >> makes all of these figures utterly
> >> meaningless anyway.
> >
> >They stated 12C
>
> No they don't. You're making it up as you go along.
It is mentioned on their web site. You will have to,look.
> >> >You will ,never run out of hot water,
> >> >although the flow will reduce when the
> >> >heat bank runs out of hot water).
> >>
> >> Like the side of a house.
> >
> >???
>
> from 25 litres per minute to 8 on a good day.
Once again you disappoint. The store is sized to suit. you can't understand
this.
> >> One could also choose different sizes
> >> of standard HW cylinder, and given a large,
> >> well insulated one could have a system that outperforms
> >> any of this.
> >
> >Once again you disappoint. The cylinders will
> > have to be very large indeed.
>
> Precisely 20% larger to achieve
> the same results as a heatbank.
Once again you disappoint. Not so.
IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> >Once again you disappoint. You must
> >contact them direct. They one on
> >display for customer to measure if they want to.
>
> WHy would I want to bother with that?
Once again you disappoint. You need to.
> >> >I see NO HVAC.
> >>
> >> Absolutely.
> >
> >Game, set and match!
>
> Not really, since I have not claimed to
> have been professionally
> involved in HVAC.
That is obvious!!!
> >> >Operating systems. What operating system have you
> >> >designed/implemeted? Don't porkie tell!!!!!
> >>
> >> I didn't claim to have implemented
> >> an operating system, if you read
> >> what I wrote, although I did design
> >> and produce a real-time kernel for
> >> a control system for one project
> >> because of the absence of anything
> >> off the shelf at the time.
> >
> >That is not an OS. that is writing an
> >app that can be compiled as part of
> >the kernel. Once again you disappoint.
>
> You have no idea of what you are talking
> about, so I am not even going
> to enter into a discussion on it with you.
What OP? UNIX?
IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> On Sun, 4 May 2003 14:33:46 +0100, "IMM" <abus...@easy.com> wrote:
>
> >
> >>
> >> If the head of the secondary is higher,
> >> the hot water coming from the
> >> boiler will mix with cooler water from
> >> the store. The effect of this
> >> will be to reduce the rate of heat
> >> transfer and to warm the store.
> >
> >You have the secondary just higher than the primary.
>
water will just go straight through the stored water.
> >Once again you disappoint. You size
> >to suit, but you if you do run out of
> >stored energy the boiler will produce
> >it instantly.
>
> At a lower rate.
Have alarge boiler and large rate.
> I already said that I discount that situation
> because there is a degradation of performance.
With a large boiler little degradation.
> >You size the system so that the store
> >compliments the boilers output.
>
> Store: "Oh boiler, you are brilliant
> at producing output!"
Andy, you are loosing it man!! You are becoming a basket case.
> >Use what the boiler has to offer, don't
> > allow it to sit there just topping up
> >hot water.
>
> ????
Once again you disappoint.
> >> >Again you disappoint. A condenser will
> >> >"overall" have greater efficiencies
> >> >on a heat bank, as it operates in a set
> >> >environment at all times.
> >>
> >> Sorry I don't buy that.
> >
> >Once again you disappoint. You will have to just accept that point.
>
> Yeah, right!.
Encouraging I do say.
> >> >Having a no-flame boiler on
> >> >heat banks and great efficiencies are had.
> >>
> >> On paper that would appear to be the case.
> >
> >Encouraging!
>
> Assuming that the vendor is telling
> the truth of course.
> >Also if you are using
> >Myson convector heaters then you have it on 80C.
>
> Noise?
On 80C you then can have it on low fan and no draughts.
Andy Hall
>
>
>> >Once again you disappoint. You size
>> >to suit, but you if you do run out of
>> >stored energy the boiler will produce
>> >it instantly.
>>
>> At a lower rate.
>
>Have alarge boiler and large rate.
>
>> I already said that I discount that situation
>> because there is a degradation of performance.
>
>With a large boiler little degradation.
To get even close to the performance of a conventional cylinder,
or even a heatbank using its stored energy, the boiler would need to
have an output greater than a domestic gas supply can provide.
>
>> >You size the system so that the store
>> >compliments the boilers output.
>>
>> Store: "Oh boiler, you are brilliant
>> at producing output!"
>
>Andy, you are loosing it man!! You are becoming a basket case.
What am I supposed to be "loosing"? Everything is tied up......
>
>> >Also if you are using
>> >Myson convector heaters then you have it on 80C.
>>
>> Noise?
>
>On 80C you then can have it on low fan and no draughts.
>
I used to have one to heat a stair well in a former house where there
was no room for a radiator. To get the rated output, it was
necessary to run the fan at high speed.
The noise didn't matter in the application where it was used, but
would be excessive in a normal room.
Andy Hall
>> >This is an overview. You can also have
>> >pressurised heat banks where the
>> >whole cylinder is under pressure with the boiler.
>>
>> Which presumably then is a professional install.......
>
>BBA. Yes. But the same expansion vessel used for CH can be used. Once
>again pressure blow-off equipment has to be used. This has to be
>"approved", unvented heat banks do not, so quick custom jobs can be made.
I think you mean vented? The issue is large amounts of hot water
under pressure.
>
>
>>
>
>> In any case this has not been my point.
>> That has been that using a
>> condensing boiler with a heatbank *and*
>> having the heatbank operating
>> the CH is a poor match - a demonstrable point.
>
>Not so.
It is - I already explained it in detail and am not going to again.
>
>> If you have the condensing boiler driving
>> a heatbank only for DHW, I have not said
>> that that would be more or less efficient
>> than a conventional 82/70 boiler since the
>> condensing boiler would be run at high temperature
>
>Not so. Heat banks can be run at 75C giving goog boiler efficiencies.
It's better than at 80, but nowhere close to what a condensing boiler
can do at lower temperatures. However, this is only relevent for CH
applications where the boiler can run at 50/30 or even less when the
really significant efficiencies can be had. At the required
temperature for DHW, whether its through a heatbank or a cylinder, the
condensing boiler is not operating optimally anyway, so the whole
rigmarole about dropping the heatbank temperature by 5 degrees just so
that the boiler is condensing is almost irrelevant and in my view a
marketing ploy. My contention is that if the heatbank is *only*
doing DHW, then fine, connect a condensing boiler to it because the
efficiency won't be far different than if it is running a conventional
cylinder. As far as the CH is concerned, there is a big difference
which is why I make the point that a condensing boiler is a poor match
for a heat bank IF the heatbank is running the CH as well. The Quid
Pro Quo is that the heatbank, doing DHW only doesn't achieve a whole
lot that can't be achieved with a conventional cylinder.
>
>> Case A. Conventional cylinder of 125 litres
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>> Boiler heats water through fast recovery coil to 60 degrees at full
>> boiler rate (e.g. 25kW)
>> Tap is turned on and water used from hot tap at rate equivalent to
>> 50kW
>> Boiler replenishes energy at 25kW rate while this is happening.
>> Net rate of heat loss is 25kW
>
>Poor example. If the store is exausted then there will be only cold water.
>Witha heat bank, the fallback is what the boiler will give you, which is
>determined by the size of the boiler.
Good example. The boiler is putting energy into the water through
the coil. If the water were coming out cold, where is the boiler
energy going? Outer space? It has to go somewhere and that is into
the water.
>
>> Case B. Heat bank of 100 litres
>> ~~~~~~~~~~~~~~~~~~~~~~
>>
>> Boiler heats water through coil or directly
>> to 75 degrees at full 25kW rate
>> Tap is turned on and water is heated via
>> plate heat exchanger and
>> mixed with cold such that the effective usage rate is 50kW.
>> Boiler replenishes at 25kW while this is happening.
>> Net rate of heat loss is 25kW.
>>
>> Both systems will run out of stored energy
>> at the same time because the energy stored
>> in 125 litres at 60 degrees is the same as in 100
>> litres at 75 degrees.
>
>But the heat bank will keep supplying hot water at a reduced rate and have
>less stored heat losses.
If I turn down the tap in either case after the store is exhausted,
the water will become warmer. There's no difference.
>
>> Both systems use energy from the boiler
>> to supplement what is being
>> taken from the store of energy.
>
>Very good observation. BUT the difference is that the heat bank has a
>fallback flowrate of what the boiler can supply. Two cheap boilers can
>(great for backup) can give 20-22 litres alone. The heat bank can be
>downsized to fit in small spaces in small British homes.
The cylinder does as well. The energy has to go somewhere. You are
trying to suggest that in the case of the heatbank, all the boiler
energy somehow gets transferred to the plate heat exchanger, whereas
with the cylinder it doesn't.
This is fundamentally untrue.
If the heatbank is a direct one then for all or substantially all of
the energy to be transferred from the boiler to the plate heat
exchanger, there would have to be little or no mixing of cold store
water with hot boiler water. In practice, I don't think that that can
be achieved. WIth an arrangement of valves, such as I described
earlier, this could be achieved, but only usefully if the boiler(s)
meet the energy usage rate. If that is done, then the whole thing can
be simplified by using a combi and done with it.
>
>> From an energy perspective, the results
>> are the same.
>
>Not so, more standing heat losses with a larger cylinder.
We had this discussion before. If there is reasonable insulation, the
standing loss is 10s of watts. I presented the calculations.
>
>
>> >> > This reduces the size of the store required,
>> >> > with the 80 litre DPS GXV it can fit under a
>> >> >kitchen worktop, supply 170 litres of 45C
>> >> >water at 25 litres/minutes flow rate, using a
>> >> >40-50,000 Btus directly connected boiler.
>> >> >Very impressive.
>> >>
>> >> until you read the entire article and
>> >> realise that they have left out
>> >> the flow figures for when the store has run out.
>> >
>> >Once again you disappoint. This will be
>> > what the boiler can provide.
>> >Ballpark: 90,000 Btus gives 10-11 litres/min.
>>
>> Exactly, and that figure is embarassing.
>
>It is as it about 12 l.min.
The Vaillant model used has an output of 17kW (58000 BTUs)
This does not add up to 12 litres/min even by your figures
>
>> for the boiler in question,
>> the max heat output is 17kW -
>> approx 2/3 of your figure or about 7-8
>> litres/min.
>
>Enough to fill a sink or even have a shower, until replenishment. Great!
I can get that out of a conventional cylinder. It's useful for a
sink, of limited used for anything else - just the same.
>
>> ... and you're trying to suggest that
>> this is an impressive solution?
>
>Of course. A small cylinder that goes under a worktop.
That may be just enough for a small flat. It would be more useful to
put it in a small cupboard and air clothes as well. The cylinder
could even be a little bigger.......
>
>> >> They also leave out
>> >> the mains cold temperature which
>> >> makes all of these figures utterly
>> >> meaningless anyway.
>> >
>> >They stated 12C
>>
>> No they don't. You're making it up as you go along.
>
>It is mentioned on their web site. You will have to,look.
Not with the tests related to the GXV. All of the important data is
missing.
>
>> >> >You will ,never run out of hot water,
>> >> >although the flow will reduce when the
>> >> >heat bank runs out of hot water).
>> >>
>> >> Like the side of a house.
>> >
>> >???
>>
>> from 25 litres per minute to 8 on a good day.
>
>Once again you disappoint. The store is sized to suit. you can't understand
>this.
I can understand completely. You can size any store to suit, be it a
heatbank or a conventional cylinder.
>>
>> Precisely 20% larger to achieve
>> the same results as a heatbank.
>
>Once again you disappoint. Not so.
>
>
What is the size difference of a heatbank vs. a cylinder for boiler
capacities of the same size to achieve the same performance conditions
of flow and run rate.?
Please explain why there is a different amount of energy in 125 litres
of water at 60 degrees vs. 100 litres at 75 degrees.
Andy Hall
>
>"Andy Hall" <an...@hall.nospam> wrote in message
>news:bn6abvc8g4h5oudtn...@4ax.com...
>
>> >Once again you disappoint. You must
>> >contact them direct. They one on
>> >display for customer to measure if they want to.
>>
>> WHy would I want to bother with that?
>
>Once again you disappoint. You need to.
I don't *need* to do anything, least of all that. The lack of proper
figures speaks for itself.
>
>
>> >> >I see NO HVAC.
>> >>
>> >> Absolutely.
>> >
>> >Game, set and match!
>>
>> Not really, since I have not claimed to
>> have been professionally
>> involved in HVAC.
>
>That is obvious!!!
From the level of complexity from what I have seen and from people
that I know who are professionally qualified (chartered engineers) in
the field, it is not difficult for most people to understand for
domestic applications and for someone with an engineering degree to
pick up for industrial purposes.
>
>> >> >Operating systems. What operating system have you
>> >> >designed/implemeted? Don't porkie tell!!!!!
>> >>
>> >> I didn't claim to have implemented
>> >> an operating system, if you read
>> >> what I wrote, although I did design
>> >> and produce a real-time kernel for
>> >> a control system for one project
>> >> because of the absence of anything
>> >> off the shelf at the time.
>> >
>> >That is not an OS. that is writing an
>> >app that can be compiled as part of
>> >the kernel. Once again you disappoint.
>>
>> You have no idea of what you are talking
>> about, so I am not even going
>> to enter into a discussion on it with you.
>
>What OP? UNIX?
>
>
As it happens I've worked with Unix at all levels for about 20 years,
and at various other levels with about another dozen.
The common distributions are not real-time in design or operation.
IMM
"Andy Hall" <an...@hall.nospam> wrote in message
> >> >Once again you disappoint. You size
> >> >to suit, but you if you do run out of
> >> >stored energy the boiler will produce
> >> >it instantly.
> >>
> >> At a lower rate.
> >
> >Have alarge boiler and large rate.
> >
> >> I already said that I discount that situation
> >> because there is a degradation of performance.
> >
> >With a large boiler little degradation.
> To get even close to the performance
> of a conventional cylinder, or even a
> heatbank using its stored energy, the
> boiler would need to have an output
> greater than a domestic gas supply
> can provide.
Once again you disappoint. 20-22 l/min is fine by most people, and that can
be juts the fallback flowrate.
> >> >You size the system so that the store
> >> >compliments the boilers output.
> >>
> >> Store: "Oh boiler, you are brilliant
> >> at producing output!"
> >
> >Andy, you are loosing it man!! You
> >are becoming a basket case.
>
> What am I supposed to be "loosing"? Everything is tied up......
You're in a straight jacket?
> >> >Also if you are using
> >> >Myson convector heaters then you have it on 80C.
> >>
> >> Noise?
> >
> >On 80C you then can have it on low fan
> > and no draughts.
>
> I used to have one to heat a stair well in
> a former house where there
> was no room for a radiator. To get the
> rated output, it was necessary to run the
> fan at high speed.
Probably too low a flow temp and pipe not large enough.
Andy Hall
>
>
>> To get even close to the performance
>> of a conventional cylinder, or even a
>> heatbank using its stored energy, the
>> boiler would need to have an output
>> greater than a domestic gas supply
>> can provide.
>
>Once again you disappoint. 20-22 l/min is fine by most people, and that can
>be juts the fallback flowrate.
But only with a huge boiler
>
>> >> >Also if you are using
>> >> >Myson convector heaters then you have it on 80C.
>> >>
>> >> Noise?
>> >
>> >On 80C you then can have it on low fan
>> > and no draughts.
>>
>> I used to have one to heat a stair well in
>> a former house where there
>> was no room for a radiator. To get the
>> rated output, it was necessary to run the
>> fan at high speed.
>
>Probably too low a flow temp and pipe not large enough.
>
82 degrees and pipes correctly sized, as always.
IMM
>
> >> In any case this has not been my point.
> >> That has been that using a
> >> condensing boiler with a heatbank *and*
> >> having the heatbank operating
> >> the CH is a poor match - a demonstrable point.
> >
> >Not so.
>
> It is - I already explained it in detail and
> am not going to again.
Please do not.
> >> If you have the condensing boiler driving
> >> a heatbank only for DHW, I have not said
> >> that that would be more or less efficient
> >> than a conventional 82/70 boiler since the
> >> condensing boiler would be run at high temperature
> >
> >Not so. Heat banks can be run at 75C giving
> >good boiler efficiencies.
>
> It's better than at 80,
Depends on the heat bank size.
> >> Case A. Conventional cylinder of 125 litres
> >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >>
> >> Boiler heats water through fast recovery coil to 60 degrees at full
> >> boiler rate (e.g. 25kW)
> >> Tap is turned on and water used from hot tap at rate equivalent to
> >> 50kW
> >> Boiler replenishes energy at 25kW rate while this is happening.
> >> Net rate of heat loss is 25kW
> >
> >Poor example. If the store is exausted
> >then there will be only cold water.
> >Witha heat bank, the fallback is what
> >the boiler will give you, which is
> >determined by the size of the boiler.
>
> Good example.
Poor example.
> >> Case B. Heat bank of 100 litres
> >> ~~~~~~~~~~~~~~~~~~~~~~
> >>
> >> Boiler heats water through coil or directly
> >> to 75 degrees at full 25kW rate
> >> Tap is turned on and water is heated via
> >> plate heat exchanger and
> >> mixed with cold such that the effective usage rate is 50kW.
> >> Boiler replenishes at 25kW while this is happening.
> >> Net rate of heat loss is 25kW.
> >>
> >> Both systems will run out of stored energy
> >> at the same time because the energy stored
> >> in 125 litres at 60 degrees is the same as in 100
> >> litres at 75 degrees.
> >
> >But the heat bank will keep supplying hot
> >water at a reduced rate and have
> >less stored heat losses.
>
> If I turn down the tap in either case
> after the store is exhausted,
> the water will become warmer. There's no difference.
You have to read again and understand more.
> >> Both systems use energy from the boiler
> >> to supplement what is being
> >> taken from the store of energy.
> >
> >Very good observation. BUT the difference is that the heat bank has a
> >fallback flowrate of what the boiler can supply. Two cheap boilers can
> >(great for backup) can give 20-22 litres alone. The heat bank can be
> >downsized to fit in small spaces in small British homes.
>
> The cylinder does as well. The energy
> has to go somewhere. You are
> trying to suggest that in the case of the
> heatbank, all the boiler energy somehow gets
> transferred to the plate heat exchanger, whereas
> with the cylinder it doesn't.
Getting there. Not trying to suggest, saying that is how it is.
> This is fundamentally untrue.
Once again you disappoint.
> If the heatbank is a direct one then
> for all or substantially all of
> the energy to be transferred from
> the boiler to the plate heat
> exchanger, there would have to
> be little or no mixing of cold store
> water with hot boiler water.
This is true.
> In practice, I don't think that that can
> be achieved.
Once again you disappoint. It can be achieved.
> WIth an arrangement of valves, such
> as I described earlier, this could be
> achieved,
It can. But if you install a header on the top of the heat bank with the
boiler feeding it and the plate heat exchanger drawing off it then no
mixing. I assume you don't know hpow a header works. Just accept that it
works.
> >> From an energy perspective, the results
> >> are the same.
> >
> >Not so, more standing heat losses with a larger cylinder.
>
> We had this discussion before.
> If there is reasonable insulation, the
> standing loss is 10s of watts.
> I presented the calculations.
Still more heat loss.
> >> >> > This reduces the size of the store required,
> >> >> > with the 80 litre DPS GXV it can fit under a
> >> >> >kitchen worktop, supply 170 litres of 45C
> >> >> >water at 25 litres/minutes flow rate, using a
> >> >> >40-50,000 Btus directly connected boiler.
> >> >> >Very impressive.
> >> >>
> >> >> until you read the entire article and
> >> >> realise that they have left out
> >> >> the flow figures for when the store has run out.
> >> >
> >> >Once again you disappoint. This will be
> >> > what the boiler can provide.
> >> >Ballpark: 90,000 Btus gives 10-11 litres/min.
> >>
> >> Exactly, and that figure is embarassing.
> >
> >It is as it about 12 l.min.
>
> The Vaillant model used has an output of 17kW (58000 BTUs)
> This does not add up to 12 litres/min even by your figures
The 12 equates to 90,000ish. re-read.
> >> for the boiler in question,
> >> the max heat output is 17kW -
> >> approx 2/3 of your figure or about 7-8
> >> litres/min.
> >
> >Enough to fill a sink or even have a
> >shower, until replenishment. Great!
>
> I can get that out of a conventional cylinder.
Once again you disappoint. Not when there is no hot water in it.
> >> ... and you're trying to suggest that
> >> this is an impressive solution?
> >
> >Of course. A small cylinder that goes under a worktop.
>
> That may be just enough for a small flat.
It can deliver 170 litre at 25 litres/min flowrate. That must be a big flat
then.
> It would be more useful to
> put it in a small cupboard and air clothes
> as well. The cylinder
> could even be a little bigger.......
It could be smaller too.
> >> >> >You will ,never run out of hot water,
> >> >> >although the flow will reduce when the
> >> >> >heat bank runs out of hot water).
> >> >>
> >> >> Like the side of a house.
> >> >
> >> >???
> >>
> >> from 25 litres per minute to 8 on a good day.
> >
> >Once again you disappoint. The store is sized
> >to suit. you can't understand this.
>
> I can understand completely.
Once again you disappoint. You can't.
> >> Precisely 20% larger to achieve
> >> the same results as a heatbank.
> >
> >Once again you disappoint. Not so.
> What is the size difference of a
> heatbank vs. a cylinder for boiler
> capacities of the same size to
> achieve the same performance conditions
> of flow and run rate.?
With heat bank the bigger the boiler the smaller the store.
> Please explain why there is a different
> amount of energy in 125 litres
> of water at 60 degrees vs. 100 litres
> at 75 degrees.
Once again you disappoint. You are O levelling it again.