Central Heating help

39 views
Skip to first unread message

Peter Parker

unread,
Apr 25, 2003, 1:52:30 AM4/25/03
to
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.
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

unread,
Apr 25, 2003, 4:49:10 AM4/25/03
to
>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.

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

unread,
Apr 25, 2003, 9:22:39 AM4/25/03
to
On Fri, 25 Apr 2003 06:52:30 +0100, Peter Parker <spi...@no.spam>
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

unread,
Apr 25, 2003, 11:28:04 AM4/25/03
to
"Peter Parker" <spi...@no.spam> wrote in message
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

unread,
Apr 25, 2003, 11:31:56 AM4/25/03
to

"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

unread,
Apr 25, 2003, 12:00:57 PM4/25/03
to
In article <b8bk8s$t29$1...@newsg1.svr.pol.co.uk>,

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

unread,
Apr 25, 2003, 12:34:21 PM4/25/03
to

"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

unread,
Apr 25, 2003, 4:26:55 PM4/25/03
to
On Fri, 25 Apr 2003 17:34:21 +0100, "IMM" <abuse: abus...@easy.com>
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

unread,
Apr 26, 2003, 8:55:43 AM4/26/03
to
"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.

> >> 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

unread,
Apr 26, 2003, 1:08:38 PM4/26/03
to
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.....

>> >
>> >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

unread,
Apr 26, 2003, 3:40:14 PM4/26/03
to
Sorry,
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

unread,
Apr 26, 2003, 5:46:56 PM4/26/03
to
On Sat, 26 Apr 2003 20:40:14 +0100, Peter Parker <spi...@no.spam>
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

unread,
Apr 27, 2003, 8:11:46 AM4/27/03
to
"Andy Hall" <an...@hall.nospam> wrote in message
news:5eclavcq7tq620n42...@4ax.com...

> 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

unread,
Apr 27, 2003, 8:22:09 AM4/27/03
to
"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.

> 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

unread,
Apr 27, 2003, 8:53:39 AM4/27/03
to
On Sun, 27 Apr 2003 13:11:46 +0100, "IMM" <abuse: abus...@easy.com>
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

unread,
Apr 27, 2003, 3:52:56 PM4/27/03
to
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?

abuse-imm@easy.com IMM

unread,
Apr 28, 2003, 5:09:36 AM4/28/03
to

"Andy Hall" <an...@hall.nospam> wrote in message
news:o5doav4p17q2ik30v...@4ax.com...

> 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

unread,
Apr 28, 2003, 5:44:18 AM4/28/03
to

"Andy Hall" <an...@hall.nospam> wrote in message
news:ssinavkgvuflrj103...@4ax.com...

> >> 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

unread,
Apr 28, 2003, 5:25:15 PM4/28/03
to
In message <b8ir79$72d$1...@newsg4.svr.pol.co.uk>, IMM
<abuse@?.?.com.invalid> writes
I noticed you missed the word "grammar" out

--
geoff

Andy Hall

unread,
Apr 28, 2003, 7:20:28 PM4/28/03
to
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.

>
>> >> 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

unread,
Apr 29, 2003, 4:26:09 AM4/29/03
to

"geoff" <ge...@ntlworld.com> wrote in message
news:JgbM0IZ7...@81.100.119.82...

I am brilliant at English too.

abuse-imm@easy.com IMM

unread,
Apr 29, 2003, 4:40:08 AM4/29/03
to

"Andy Hall" <an...@hall.nospam> wrote in message
news:72dravc8ilmd0eptc...@4ax.com...

> 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

unread,
Apr 29, 2003, 8:45:11 AM4/29/03
to
On Tue, 29 Apr 2003 09:40:08 +0100, "IMM" <abuse: abus...@easy.com>
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

unread,
Apr 29, 2003, 10:36:30 AM4/29/03
to

"Andy Hall" <an...@hall.nospam> wrote in message
news:qcssavop9ei4s3rdp...@4ax.com...

> >> >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

unread,
Apr 29, 2003, 3:18:55 PM4/29/03
to
On Tue, 29 Apr 2003 15:36:30 +0100, "IMM" <abuse: abus...@easy.com>
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

unread,
Apr 29, 2003, 5:21:43 PM4/29/03
to
"Andy Hall" <an...@hall.nospam> wrote in message
news:a3jtavo509ugo9ps1...@4ax.com...

> >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

unread,
Apr 29, 2003, 6:19:02 PM4/29/03
to
On Tue, 29 Apr 2003 22:21:43 +0100, "IMM" <abuse: abus...@easy.com>
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

unread,
Apr 29, 2003, 6:32:40 PM4/29/03
to
In message <b8ld1r$47q$1...@news7.svr.pol.co.uk>, IMM
<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

unread,
Apr 29, 2003, 6:43:02 PM4/29/03
to

"Andy Hall" <an...@hall.nospam> wrote in message
news:1istav4vlh63apfee...@4ax.com...

> >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

unread,
Apr 29, 2003, 6:43:58 PM4/29/03
to

"geoff" <ge...@ntlworld.com> wrote in message
news:2hnT0vGI...@81.100.119.82...

You need to learn to spoke proper.

Andy Hall

unread,
Apr 29, 2003, 7:23:33 PM4/29/03
to
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?

>
>> >> 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

unread,
Apr 30, 2003, 6:38:38 AM4/30/03
to

"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.

> >> >> 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

unread,
Apr 30, 2003, 7:50:32 AM4/30/03
to
On Wed, 30 Apr 2003 11:38:38 +0100, "IMM" <abuse: abus...@easy.com>
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

unread,
Apr 30, 2003, 8:42:55 AM4/30/03
to

"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. 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

unread,
Apr 30, 2003, 9:46:11 AM4/30/03
to
On Wed, 30 Apr 2003 13:42:55 +0100, "IMM" <abuse: abus...@easy.com>
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

unread,
Apr 30, 2003, 10:36:20 AM4/30/03
to
"Andy Hall" <an...@hall.nospam> wrote in message
news:o0ivav82v6fl19pal...@4ax.com...

> >> >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

unread,
Apr 30, 2003, 1:24:52 PM4/30/03
to
On Wed, 30 Apr 2003 15:36:20 +0100, "IMM" <abuse: abus...@easy.com>
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

unread,
Apr 30, 2003, 3:46:20 PM4/30/03
to
"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.

> >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

unread,
Apr 30, 2003, 5:18:31 PM4/30/03
to
On Wed, 30 Apr 2003 20:46:20 +0100, "IMM" <abuse: abus...@easy.com>
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

unread,
May 1, 2003, 9:31:47 AM5/1/03
to

"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.

> >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

unread,
May 1, 2003, 9:58:12 AM5/1/03
to
>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.

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

unread,
May 1, 2003, 11:44:12 AM5/1/03
to

"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

unread,
May 1, 2003, 11:54:32 AM5/1/03