Looking for Info on Pool Solar Heating in NJ
John W. Moffett
Hello all,
I live in New Jersey with a well shaded pool. Have nice sunny roof and
would like to use solar to warm up the pool by 10 degrees. Local pool
stores are no help - if it isn't gas fired they don't do it.
I am having trouble finding dealers, installers, and others with
experience with pool solar heaters. (Like, one local pool store warned
that squirrels will eat the panels! Any truth to that one?)
Any experience with solar in the North East appreciated.
Thanks,
j.w.m...@worldnet.att.net
Nick Pine
John W. Moffett <j.w.m...@worldnet.att.net> wrote:
>Hello all,
Hello John,
>I live in New Jersey with a well shaded pool. Have nice sunny roof and
>would like to use solar to warm up the pool by 10 degrees.
How about floating two dozen $16 2' x 8' x 2" thick pieces of Styrofoam on the
pool, and putting a layer of 5 cent/ft^2 black polyethylene film on your sunny
roof, and putting another layer of clear film over that, attached with some
75 cent/linear foot aluminum extrusion clamps, and drilling a 1/8" hole every
6" in a 1 1/2" PVC pipe along the ridgeline, to spray some pump filter water
between the two plastic films, which runs down into the gutter and back into
the pool, whenever the sun is shining and the pool is not warm enough?
The weak point in solar pool heating is usually the cover, which is a poor
insulator, compared to a house wall. A 24' x 32' 80 F pool with an outdoor
temp T might lose 24(80-T)768ft^2/R10 Btu/day through a 2" Styrofoam cover,
and a rooftop with a south-facing area of 20' x 32' might gain 640K Btu/day
of winter sun, and lose (6 hr)(80-T)640ft^2/R1, so if Ein = Eout,
24(80-T)76.8 = 6(80-T)640, or equivalently,
4(80-T)76.8 = (80-T)640, or equivalently,
(80-T)76.8 = (80-T)160, or equivalently,
76.8 = 160.
Hmmm. What is wrong with this solar arithmetic? Is it true that solar heating
does not work, as many people say?
Aha, I forgot the sun...
24(80-T)76.8 = 640K - 6(80-T)640, or equivalently,
(80-T)76.8 = 26.7K -6(80-T)26.7, or equivalently,
(80-T)(76.8+160) = 26.7K, or equivalently,
(80-T)236.8 = 26.7K, or equivalently,
80-T = 26.7K/236.8, or equivalently,
80-T = 112.8, or equivalently,
T = 80 - 112.8 = - 32.8.
So, could this pool stay 80 F when the outdoor temp is minus 33 F? Probably
not, since there would be some evaporation of water and heat losses between
the floating panels, and losses to the cool ground around the sides, and 55 F
R10 ground under the bottom, but still... Not bad.
How hot could we make the pool, with this arithmetic? In Philadelphia,
in December, with an average outdoor temperature of 36 F? Tp-36 = 112.8,
so Tp = 112.8 + 36 = 148.8 F. Could we make it a 104 F hot tub?
How much would it cool over a cloudy week? If it were 4' deep, and most of
the heat loss were through its R10 cover, it would hold C = (24x32)x4x64,
about 200,000 pounds of water, with a thermal resistance R = R10/(24x32), so
RC = R10/(24x32)x(24x32)x4x64 = 10x4x64 = 2560 hours or 106 days or 15 weeks.
Over one week, it might cool to 36 + (104-36)exp(-1/15) = 99.7 F.
Nick
Andy Burgess
Nick Pine writes:
>John W. Moffett <j.w.m...@worldnet.att.net> wrote:
>>I live in New Jersey with a well shaded pool. Have nice sunny roof and
>>would like to use solar to warm up the pool by 10 degrees.
>How about floating two dozen $16 2' x 8' x 2" thick pieces of Styrofoam on the
>pool,
<actual heater idea deleted, good one Nick!>
An idea for insulating pools is to float styrofoam spheres (1-2 inches
in diameter or so, a couple of spheres deep). That way you insulate and can
still swim without messing with the insulation. I don't know if styrofoam
popcorn used for packing would work -- might saturate and sink but worth
experimenting with outside the pool perhaps.
Even air filled plastic balls would help insulate and allow pool use.
Good luck.
--
Best regards,
Andy Burgess
a...@cichlid.com
Nick Pine
Andy Burgess <a...@cichlid.com> wrote:
>Nick Pine wrotes about:
>>...floating 2 dozen $16 2' x 8' x 2" thick pieces of Styrofoam on the pool,
Oops. That shoulda been 2 dozen $8 2' x 8' x 2" thick pieces of Styrofoam.
Still a lot of stuff to get out of the way when you want to go for a swim.
><actual heater idea deleted, good one Nick!>
Thank you :-)
>An idea for insulating pools is to float styrofoam spheres (1-2 inches
>in diameter or so, a couple of spheres deep). That way you insulate and can
>still swim without messing with the insulation.
You can? Hmmm. Underwater, maybe.
>I don't know if styrofoam popcorn used for packing would work -- might
>saturate and sink but worth experimenting with outside the pool perhaps.
I think that popcorn is more like beadboard than Styrofoam,
ie, white, not blue or pink. Oh wait, I've seen pink...
Would a lot of kids probably swallow the popcorn and drown?
>Even air filled plastic balls would help insulate and allow pool use.
One place I worked used ping-pong balls to cover their IC boiling bath.
How about putting the popcorn in a heat-sealed polyethylene film pillow?
Or filling the pillow with soap bubbles, and squeezing them out through
a filter to break them down into 200 times less liquid by volume when
the pillow is rolled up?
Nick
Seamus
a...@cichlid.com (Andy Burgess) gave that:
>Nick Pine writes:
>
>>John W. Moffett <j.w.m...@worldnet.att.net> wrote:
>
>>>I live in New Jersey with a well shaded pool. Have nice sunny roof and
>>>would like to use solar to warm up the pool by 10 degrees.
>
>>How about floating two dozen $16 2' x 8' x 2" thick pieces of Styrofoam on the
>>pool,
>
><actual heater idea deleted, good one Nick!>
>
>An idea for insulating pools is to float styrofoam spheres (1-2 inches
>in diameter or so, a couple of spheres deep). That way you insulate and can
>still swim without messing with the insulation. I don't know if styrofoam
>popcorn used for packing would work -- might saturate and sink but worth
>experimenting with outside the pool perhaps.
>
>Even air filled plastic balls would help insulate and allow pool use.
>
>Good luck.
>--
Yes, I found that it sinks or becomes sticky, saturated, heavy
and obnoxious to handle.(In the pool.)
Floating bubble plastic from an elevating counterpoised
roller, with balancers to auto spread the sheet on the surface, works
and stops heat loss by evaporation dead. The bubble plastic can be
recycled from commercial sources and NOT joined by sticky tape as it
degrades, but coarsely sewn with a manmade yarn such as agricultural
bale binder twine. This works. Bear in mind that if the pool is not
shaded or indoor, then these materials are UV degradable.
This cover is manually workable by one ordinary unfit person
in under a minute.
Best regards, Jim
Andrew McKegney
"John W. Moffett" <j.w.m...@worldnet.att.net> wrote:
>Hello all,
>I live in New Jersey with a well shaded pool. Have nice sunny roof and
>would like to use solar to warm up the pool by 10 degrees. Local pool
>stores are no help - if it isn't gas fired they don't do it.
>I am having trouble finding dealers, installers, and others with
>experience with pool solar heaters. (Like, one local pool store warned
>that squirrels will eat the panels! Any truth to that one?)
>Any experience with solar in the North East appreciated.
>Thanks,
>j.w.m...@worldnet.att.net
Well John it seems you have been given a couple of real neat
suggestions (Plastic sheets on the roof, floating styrafoam balls !<)-
impractical and inefficient, but neat.
Are there not any regular solar pool heating installers in your neck
of the woods? There are several good solar pool heating products
available that have been around for many years , Fafco, Heliocol,
Solar Industries, etc. These products come with guarantees and proven
track records.
About the squirrels - yes I have seen it in two of maybe 500 systems.
Rubber systems are sometimes chewed by racoons - I call the stuff
"Racoon liquorish".
Check the yellow pages in your area under solar heating to find local
installers. If you have no luck there, e-mail me and I'll see what I
can find for you.
For some ideas, check my web pages at www.pathcom.com/~sunone
Post script. Heavily shaded pools need alot of heat. A solar system
using as much as 100% of the pool surface might be in order. Also a
solar blanket to keep the heat in a t night is a must.
Andrew McKegney C.E.T.
President, Solar Evaluation Services.
18 years of full-time solar experience
Nick Pine
Andrew McKegney <sun...@pathcom.com> wrote:
>...it seems you have been given a couple of real neat suggestions
>(Plastic sheets on the roof, floating styrafoam balls !<)-
>impractical and inefficient, but neat.
Care to explain why plastic sheets on the roof are impractical? There are
about 15,000 acres of greenhouses in the United States, and about 65% of them
have polyethylene film roofs, 15 square miles of such roofs with no solid
material underneath, sprinkled all over the country. Professor Bill Roberts
at Rutgers works with one New Jersey greenhouse that measures 1320 x 250',
ie 7.5 acres. The one next door measures 1000 x 290', 6.7 acres. Many growers
use inexpensive aluminum extrusion clamps to hold the film, making it easy
to change and recycle it every 3 years or so.
And why is efficiency is so important, vs cost-effectiveness?
And why do you seem to be in love with "hi-tech" systems?
Swimming in Styrofoam balls may not be everyone's cup of tea, nor was it my
suggestion. Perhaps a layer of tiny foam bubbles would work better, with some
way to kill them quickly, C02 or dust, or some sort of non-toxic solvent? Make
bubbles inside a floating pool cover sandwich? Roll it all up automatically,
in a minute? Tiny cold bubbles have about the same R-value as fiberglass...
One might deflate 'em to let the sun shine in during the day.
So, speaking for the established greedy ignorant unimaginative shortsighted
solar pool industry collection of criminals slavering after government
subsidies, Andrew, where are _your_ R10 pool covers?
A friend of mine invented one, also not everyone's cup of tea: a tracked
tennis court over a pool, with motors that slid the court back at the touch
of a button. He enjoyed inventing that horse.
Now where can I buy that foam blanket system? UV-poly comes in big pieces, eg
rolls 32' wide by 100' long that cost $160 and weigh 75 pounds, eg from Geiger
at (800) 4GEIGER or ecgs...@hortnet.com or http://www.hortnet.com. It's easy
to heat seal. Do you own an iron?
Nick
(who doesn't own a pool, but used just 25 gallons of oil and no wood or
electrical power to heat his low-tech 1820 4 bedroom stone house with the
new steep south polycarbonate plastic roof last winter, and plans to use
less this winter :-)
Andrew McKegney
ni...@ufo.ee.vill.edu (Nick Pine) wrote:
>Andrew McKegney <sun...@pathcom.com> wrote:
>
>>...it seems you have been given a couple of real neat suggestions
>>(Plastic sheets on the roof, floating styrafoam balls !<)-
>>impractical and inefficient, but neat.
>Care to explain why plastic sheets on the roof are impractical? There are
>about 15,000 acres of greenhouses in the United States, and about 65% of them
>have polyethylene film roofs, 15 square miles of such roofs with no solid
>material underneath, sprinkled all over the country. Professor Bill Roberts
>at Rutgers works with one New Jersey greenhouse that measures 1320 x 250',
>ie 7.5 acres. The one next door measures 1000 x 290', 6.7 acres. Many growers
>use inexpensive aluminum extrusion clamps to hold the film, making it easy
>to change and recycle it every 3 years or so.
I didn't say it wouldn't work! It is very impractical for the average
pool / home owner! The maintenance on such a system would be
horrendous compared to a conventional solar pool heater. What about
the roof itself? Fastening clamps to a standard asphalt shingle roof
and then two layers of poly and then supply piping. What about water
under the plastic rotting the roof ..... there are just so many
drawbacks to this concept for 99% of the potential sites that the
concept is impratical.
>And why is efficiency is so important, vs cost-effectiveness?
This approach would be significantly more expensive than conventional
solar panels if you put ANY value to your time to maintain it.
>And why do you seem to be in love with "hi-tech" systems?
I love only systems that work and have proven track records.
>Swimming in Styrofoam balls may not be everyone's cup of tea, nor was it my
>suggestion. Perhaps a layer of tiny foam bubbles would work better, with some
>way to kill them quickly, C02 or dust, or some sort of non-toxic solvent? Make
>bubbles inside a floating pool cover sandwich? Roll it all up automatically,
>in a minute? Tiny cold bubbles have about the same R-value as fiberglass...
>One might deflate 'em to let the sun shine in during the day.
>So, speaking for the established greedy ignorant unimaginative shortsighted
>solar pool industry collection of criminals slavering after government
>subsidies, Andrew, where are _your_ R10 pool covers?
There is no such cover that I know of, which is too bad. But the
insulation value of a cover is of little value if the cover is opaque.
Pools heat up naturally by virtue of the sun shining on them. If you
have an opaque cover the pool does not get warm - unless you use a
pool heater. If you have an opaque cover or a shaded pool you are
going to need a more powerfull heater (larger solar system).
What a solar blanket really does is prevent water from evapourating
from the pool. Most heat loss in a pool is from evapouration. Putting
a blanket on the pool can reduce its' heat loss by 70%. (this make
pools much easier to keep warm). On indoor pools they keep the
humidity down, so that less ventilation is required.
>A friend of mine invented one, also not everyone's cup of tea: a tracked
>tennis court over a pool, with motors that slid the court back at the touch
>of a button. He enjoyed inventing that horse.
This concept sounds really cost-effective !<) , but if it works,
great. What about the other 6,000,000 (conservative estimate) pools in
the US?
>Now where can I buy that foam blanket system? UV-poly comes in big pieces, eg
>rolls 32' wide by 100' long that cost $160 and weigh 75 pounds, eg from Geiger
>at (800) 4GEIGER or ecgs...@hortnet.com or http://www.hortnet.com. It's easy
>to heat seal. Do you own an iron?
Blue Sheild makes a foam blanket. You just shouldn't use it of the
pool during the day (because it's opaque). (1/8" of foam) It's easily
rolled onto a conventional roller, but the foam does soak up water
after a while and gets rather heavy.
Andy McKegney C.E.T.
Nick Pine
Andrew McKegney <sun...@pathcom.com> wrote:
>>>...it seems you have been given a couple of real neat suggestions
>>>(Plastic sheets on the roof, floating styrafoam balls !<)-
>>>impractical and inefficient, but neat.
>
>>Care to explain why plastic sheets on the roof are impractical? There are
>>about 15,000 acres of greenhouses in the United States, and about 65% of them
>>have polyethylene film roofs, 15 square miles of such roofs with no solid
>>material underneath, sprinkled all over the country. Professor Bill Roberts
>>at Rutgers works with one New Jersey greenhouse that measures 1320 x 250',
>>ie 7.5 acres. The one next door measures 1000 x 290', 6.7 acres. Many growers
>>use inexpensive aluminum extrusion clamps to hold the film, making it easy
>>to change and recycle it every 3 years or so.
I wonder why most solar heating professionals completely ignore the greenhouse
industry, who have been working with inexpensive and practical outdoor
transparent structures for years. And vice versa...
>I didn't say it wouldn't work!
Well, good...
>It is very impractical for the average pool / home owner!
So you said... What you tell us three times is true?
>The maintenance on such a system would be horrendous compared to a
>conventional solar pool heater.
I disagree. It might be less, with less plumbing and valves and so on.
Have you ever worked for Western Union? Many executives there had their very
own telegraph keys and sounders on their desks, in 1975. Some of the sounders
were attached to tobacco tins with slots cut in the tins to vary the sound,
so they could more easily follow their sounders in rooms full of sounders.
Really quite clever. The company's technically more advanced Chief Engineer
was building 110 volt flip-flops out of discrete transistors, with load
resistors made from hundreds of feet of nichrome strips, in 1975. Everyone
had high blood pressure. Nobody liked to talk about fax machines. Sometimes
it pays to take a fresh look at things, even when heating swimming pools...
>What about the roof itself?
Perhaps it would last longer, with the shingles all covered with plastic.
>Fastening clamps to a standard asphalt shingle roof
>and then two layers of poly and then supply piping.
Horrible thought, eh? I suppose the clamps might go on the sides of the house,
not screwed right flat on the roof. The upper layer of plastic would have to
be changed and recycled every 3 years or so, perhaps less often if it had
shadecloth over it in the summer (another useful greenhouse product, seldom
seen elsewhere, at 15 cents/ft^2, with an outdoor lifetime of 10 years (?))
Changing the poly film should take less than an hour, on a calm day, at a
cost of 5 cents/ft^2. Perhaps this thing should have one 2" PVC supply pipe.
Should the plastic be draped over the ridge pipe?
>What about water under the plastic rotting the roof...
That's a helpful thought. There IS work to be done, to make this practical.
Richard Komp says that the large polyethylene sheets for sale 20 years ago
in hardware stores had pinholes. Have things improved since then? Should the
lower layer be EPDM rubber, which lasts forever, with standing seams on the
roof that serve to help space the poly film over it, with a few plastic ropes
or boards or old tires over the film to keep it from billowing in the wind?
Perhaps a few leaks won't matter. Roofs do get wet, and they don't have vapor
barriers underneath.
>there are just so many drawbacks to this concept for 99% of the potential
>sites that the concept is impratical.
So you said, twice before. Does it have to be spelled right this time, to
make it true? How can a man who displays such attention to detail presume
to lecture us on roof practicalities?
>>And why is efficiency is so important, vs cost-effectiveness?
Well?
>This approach would be significantly more expensive than conventional
>solar panels if you put ANY value to your time to maintain it.
You mean, 1 hour every 3 years? :-)
>>And why do you seem to be in love with "hi-tech" systems?
>I love only systems that work and have proven track records.
Like cruise missiles?
>>Swimming in Styrofoam balls may not be everyone's cup of tea, nor was it my
>>suggestion. Perhaps a layer of tiny foam bubbles would work better, with some
>>way to kill them quickly, C02 or dust, or hot air? Make bubbles inside a
>>floating pool cover sandwich? Roll it all up automatically, in a minute?
>>Tiny cold bubbles have about the same R-value as fiberglass...
>>One might deflate 'em to let the sun shine in during the day.
>>So, speaking for the established greedy ignorant unimaginative shortsighted
>>solar pool industry collection of criminals slavering after government
>>subsidies, Andrew, where are _your_ R10 pool covers?
>There is no such cover that I know of, which is too bad.
How pro-active. You know where to buy the UV poly. Start with a hot tub, and
an $80 200 in^3/min 7 psi peak, 2 psi continuous duty Danner dynamaster (800)
893-4220 piston air pump, 110VAC at 0.66 Amps, or their 120 in^3/min 12VAC
version, or the $169 1.8 cfm 4-10 psi WP120 12VDC 7 Amp diaphram air pump
from Jade Mountain at (800) 442-1972, jade...@indra.com, feeding a large
airstone or screened well point filter? A 7x7' pool cover filled with 6" of
bubbles has a volume of about 25 ft^3, and 1 cfm will fill that in less than
a half-hour. If the bubbles last 2 hours, the pump would have to run about
20% of the time. Tiny bubbles have an expansion ratio of 200:1, which means
the soapy water container needs to hold about 0.125 ft^3 or 1 gallon of a
2% Green Dawn solution (?)
There's a hot tub air blower in the Grainger catalog, $193 for their 2P681
35 cfm at 115 VAC, 6.6 Amps. Yes, this is a bad habit, but maybe that blower
can also be used to inflate the bubble foam cover, somehow...
A 24x32' pool cover filled with 6" of bubbles would have a volume of 384 ft^3,
requiring a 16 gallon soapy water container and a larger air pump, eg the $58
Grainger 4C442 140 cfm 0.95" blower, which uses 1 Amp at 110VAC. (This blower
is used to inflate 2 layers of plastic film on commercial greenhouses, 24
hours a day, to prevent wind fatigue. CT Film's rule of thumb is that 1/30
blower horsepower protects 10,000 ft^2 of poly pillow area, so this blower
should work for a greenhouse up to about 1 acre. Would it protect a rooftop
film pool heater, with a wind switch? Probably so.) A bubble foam pool cover
might be inflated by bubbles that come out of a 30 gallon plastic drum full
of soapy water buried in the ground, with a 2" hose from the blower, mounted
on top of the drum, disappearing down into the center of a 14" diameter
floating platform in the drum, supported by a floating ring, with a piece
of plastic window screen around the hose. The foam needs recycling somehow,
perhaps through a filter to separate it into water and air.
>insulation value of a cover is of little value if the cover is opaque.
What preposterous rubbish. Are your house walls transparent?
>Pools heat up naturally by virtue of the sun shining on them.
About 500 Btu/ft^2 per day in the winter, where I live. But they lose about
24 hours(76-36)R1 = 960 Btu/day through an R1 cover, and solar pool covers
are R1 at best. An R10 opaque cover is far more efficient. And we are much
better off than that, with a film to prevent evaporation at all times, and
an insulating cover that retracts during the day. Or a deflated bubble foam
cover to let in the sun during the day that is pumped back up with bubbles
at night. And a $500 commercial plastic film greenhouse over it all, with
white poly film on the north half, with the pool running east and west, to
reflect closer to 1000 Btu/ft^2/day down into the pool in the winter.
>If you have an opaque cover the pool does not get warm - unless you use a
>pool heater.
Duh. It actually stays fairly warm, perhaps warmer than with a cover,
because of heat from the ground. A little jet engine under the pool
might help here too, to extract ground heat at a higher temperature.
And fer Chrissake some insulation around the sides of the pool.
>If you have an opaque cover or a shaded pool you are
>going to need a more powerfull heater (larger solar system).
Duh^2. And perhaps a spellchecker.
>What a solar blanket really does is prevent water from evapourating
>from the pool. Most heat loss in a pool is from evapouration. Putting
>a blanket on the pool can reduce its' heat loss by 70%. (this make
>pools much easier to keep warm).
Let's try that again.
>What a solar blanket really does is prevent water from evaporating
>from the pool. Most heat loss in a pool is from evaporation. Putting
>a blanket on the pool can reduce its heat loss by 70%. (This makes
>pools much easier to keep warm).
Duh^3. Most third-graders could figure that out.
>>A friend of mine invented one, also not everyone's cup of tea: a tracked
>>tennis court over a pool, with motors that slid the court back at the touch
>>of a button. He enjoyed inventing that horse.
>This concept sounds really cost-effective !<) , but if it works, great.
It was cheaper than filling his sloping lot for a separate tennis court.
>What about the other 6,000,000 (conservative estimate) pools in the US?
Not my job. What are you doing about that, Andy? Just selling the same
old stuff, I guess. High-priced buckets for bottomless boats.
>>Now where can I buy that foam blanket system? UV-poly comes in big pieces,
>>eg rolls 32' wide by 100' long that cost $160 and weigh 75 pounds, eg from
>>Geiger at (800) 4GEIGER or ecgs...@hortnet.com or http://www.hortnet.com.
>>It's easy to heat seal. Do you own an iron?
Well?
>Blue Sheild makes a foam blanket. You just shouldn't use it of the
>pool during the day (because it's opaque). (1/8" of foam)
An R-value of 1/2, if perfectly dry?
>It's easily rolled onto a conventional roller, but the foam does soak up water
>after a while and gets rather heavy.
Do you think that might somehow affect its insulation value?
Nick
"Just the place for a Snark! I have said it twice.
That alone should encourage the crew.
Just the place for a Snark! I have said it thrice:
What I tell you three times is true."
The crew was complete: it included a Boots--
A maker of Bonnets and Hoods--
A barrister, brought to arrange their disputes--
And a broker, to value their goods.
A solar pool heating professional,
Might perhaps have won more than his share--
But a banker, engaged at enormous expense,
Had the whole of their cash in his care...
Nick Pine
Nick Pine <ni...@ufo.ee.vill.edu> wrote:
>Start with a hot tub, and an $80 200 in^3/min 7 psi peak, 2 psi continuous
>duty Danner dynamaster (800) 893-4220 piston air pump, 110VAC at 0.66 Amps,
Just found out they also have a 12VDC, 2A "Challenger" version.
About the same price, I suppose...
Nick
Andrew McKegney
ni...@ufo.ee.vill.edu (Nick Pine) wrote:
>I wonder why most solar heating professionals completely ignore the greenhouse
>industry, who have been working with inexpensive and practical outdoor
>transparent structures for years. And vice versa...
>>I didn't say it wouldn't work!
>Well, good...
>>It is very impractical for the average pool / home owner!
>So you said... What you tell us three times is true?
>>The maintenance on such a system would be horrendous compared to a
>>conventional solar pool heater.
>I disagree. It might be less, with less plumbing and valves and so on.
Nick you have already stated that the plastic would have to be
replaced every 3 years. That's 400 % more maintenance (minimum) than a
conventional solar system.
Sometimes
>it pays to take a fresh look at things, even when heating swimming pools...
No doubt about that. But I would guess that 90% of inovation comes
from people within an industry trying to find a more cost-effective
way THAT WORKS.
>>What about the roof itself?
>Perhaps it would last longer, with the shingles all covered with plastic.
No it won't. This is a known problem with solar systems. The roof must
be allowed to dry out. (applicable to asphalt shingle tiles
specifically)
>>Fastening clamps to a standard asphalt shingle roof
>>and then two layers of poly and then supply piping.
>Horrible thought, eh? I suppose the clamps might go on the sides of the house,
>not screwed right flat on the roof. The upper layer of plastic would have to
>be changed and recycled every 3 years or so, perhaps less often if it had
>shadecloth over it in the summer (another useful greenhouse product, seldom
>seen elsewhere, at 15 cents/ft^2, with an outdoor lifetime of 10 years (?))
>Changing the poly film should take less than an hour, on a calm day, at a
>cost of 5 cents/ft^2. Perhaps this thing should have one 2" PVC supply pipe.
>Should the plastic be draped over the ridge pipe?
Less than an hour to remove and reinstall hundreds of square feet of
plastic on a roof.... what dream world are you living in? This is
almost a full days job!!!!
>>What about water under the plastic rotting the roof...
>That's a helpful thought. There IS work to be done, to make this practical.
>Richard Komp says that the large polyethylene sheets for sale 20 years ago
>in hardware stores had pinholes. Have things improved since then? Should the
>lower layer be EPDM rubber, which lasts forever, with standing seams on the
>roof that serve to help space the poly film over it, with a few plastic ropes
>or boards or old tires over the film to keep it from billowing in the wind?
>Perhaps a few leaks won't matter. Roofs do get wet, and they don't have vapor
>barriers underneath.
EPDM rubber is a lot more expensive than poly-plastic sheeting.
Boards & tires????? You've got to be kidding. Do you think people are
going to want their roofs to look like garbage dumps????
>>there are just so many drawbacks to this concept for 99% of the potential
>>sites that the concept is impratical.
>So you said, twice before. Does it have to be spelled right this time, to
>make it true? How can a man who displays such attention to detail presume
>to lecture us on roof practicalities?
Get real. My point in replying to this thread was to illustrate that
while it may be possible for a do-it-yourselfer to patch together a
solar pool heating system from materials from "Home Depot", that
system will take a great deal of TIME and effort, a good deal of
skilled workmanship and not a small amount of money (if the system is
designed to deliver the same amount of heat as a conventional solar
system).
>>>And why is efficiency is so important, vs cost-effectiveness?
>Well?
It's not....IF.....the cost-effectiveness takes into account the
lifetime costs , including the time for maintenance. Most (maybe 98%)
pool owners want a pool heater they can forget about after it's
installed - hence the popularity of gas heaters (until they see the
gas bills). Systems that require a lot of maintenance will eventually
be neglected (real world situation). Efficiency also means the system
can be smaller, which means it will fit where less efficient systems
can't.
>>This approach would be significantly more expensive than conventional
>>solar panels if you put ANY value to your time to maintain it.
>You mean, 1 hour every 3 years? :-)
See above.
>>>And why do you seem to be in love with "hi-tech" systems?
>
>>I love only systems that work and have proven track records.
>Like cruise missiles?
Like Solar energy systems ...................
Andrew, where are _your_ R10 pool covers?
>
>>There is no such cover that I know of, which is too bad.
>How pro-active. You know where to buy the UV poly. Start with a hot tub, and
>an $80 200 in^3/min 7 psi peak, 2 psi continuous duty Danner dynamaster (800)
>893-4220 piston air pump, 110VAC at 0.66 Amps, or their 120 in^3/min 12VAC
>version, or the $169 1.8 cfm 4-10 psi WP120 12VDC 7 Amp diaphram air pump
>from Jade Mountain at (800) 442-1972, jade...@indra.com, feeding a large
>airstone or screened well point filter? A 7x7' pool cover filled with 6" of
>bubbles has a volume of about 25 ft^3, and 1 cfm will fill that in less than
>a half-hour. If the bubbles last 2 hours, the pump would have to run about
>20% of the time. Tiny bubbles have an expansion ratio of 200:1, which means
>the soapy water container needs to hold about 0.125 ft^3 or 1 gallon of a
>2% Green Dawn solution (?)
>There's a hot tub air blower in the Grainger catalog, $193 for their 2P681
>35 cfm at 115 VAC, 6.6 Amps. Yes, this is a bad habit, but maybe that blower
>can also be used to inflate the bubble foam cover, somehow...
As far as I can determine, you're talking about a spa cover here.
That's a far far cry from a full size pool. There are lots of R-10
(and better) spa covers available. Pools are a much bigger problem.
>A 24x32' pool cover filled with 6" of bubbles would have a volume of 384 ft^3,
>requiring a 16 gallon soapy water container and a larger air pump, eg the $58
>Grainger 4C442 140 cfm 0.95" blower, which uses 1 Amp at 110VAC. (This blower
>is used to inflate 2 layers of plastic film on commercial greenhouses, 24
>hours a day, to prevent wind fatigue. CT Film's rule of thumb is that 1/30
>blower horsepower protects 10,000 ft^2 of poly pillow area, so this blower
>should work for a greenhouse up to about 1 acre. Would it protect a rooftop
>film pool heater, with a wind switch? Probably so.) A bubble foam pool cover
>might be inflated by bubbles that come out of a 30 gallon plastic drum full
>of soapy water buried in the ground, with a 2" hose from the blower, mounted
>on top of the drum, disappearing down into the center of a 14" diameter
>floating platform in the drum, supported by a floating ring, with a piece
>of plastic window screen around the hose. The foam needs recycling somehow,
>perhaps through a filter to separate it into water and air.
This cover mighr be fine if you never intended to remove it. A major
factor in the regular use of pool blanket is the ease of installing
and removing the cover. Given that a 1/4 inch thick blanket that rolls
easily onto a roller at the end of the pool is considered an
inconvienence by most pool owners, I can imagine their reaction to the
inflatable monstor you're proposing!
>>insulation value of a cover is of little value if the cover is opaque.
>What preposterous rubbish. Are your house walls transparent?
Glass walls -what a new concept !<)
The insulation value of a cover is of little value if the cover is
opaque.
>>Pools heat up naturally by virtue of the sun shining on them.
>About 500 Btu/ft^2 per day in the winter, where I live. But they lose about
>24 hours(76-36)R1 = 960 Btu/day through an R1 cover, and solar pool covers
>are R1 at best. An R10 opaque cover is far more efficient. And we are much
>better off than that, with a film to prevent evaporation at all times, and
>an insulating cover that retracts during the day. Or a deflated bubble foam
>cover to let in the sun during the day that is pumped back up with bubbles
>at night. And a $500 commercial plastic film greenhouse over it all, with
>white poly film on the north half, with the pool running east and west, to
>reflect closer to 1000 Btu/ft^2/day down into the pool in the winter.
>>If you have an opaque cover the pool does not get warm - unless you use a
>>pool heater.
>Duh. It actually stays fairly warm, perhaps warmer than with a cover,
>because of heat from the ground.
The temperature of the ground averages 50 Degrees F. in my part of the
world, and not much higher in most of the continental US. 50 degrees
is way-cold for a swimming pool. 82-85 degrees is where most pool
owners would like to be.
A little jet engine under the pool
>might help here too, to extract ground heat at a higher temperature.
>And fer Chrissake some insulation around the sides of the pool.
Sure let's install insulation under the existing 6,000,000 existing
pools!
Duh!!! Little jet engine!!! Why not a little nuclear reactor!! Then
you wouldn't create carbon dioxide while heating your pool!
>>If you have an opaque cover or a shaded pool you are
>>going to need a more powerfull heater (larger solar system).
>Duh^2. And perhaps a spellchecker.
Picky, picky
>>What a solar blanket really does is prevent water from evapourating
>>from the pool. Most heat loss in a pool is from evapouration. Putting
>>a blanket on the pool can reduce its' heat loss by 70%. (this make
>>pools much easier to keep warm).
>Duh^3. Most third-graders could figure that out.
Yet, you consider this irrelavent.
>>>A friend of mine invented one, also not everyone's cup of tea: a tracked
>>>tennis court over a pool, with motors that slid the court back at the touch
>>>of a button. He enjoyed inventing that horse.
>
>>This concept sounds really cost-effective !<) , but if it works, great.
>It was cheaper than filling his sloping lot for a separate tennis court.
>>What about the other 6,000,000 (conservative estimate) pools in the US?
>Not my job. What are you doing about that, Andy? Just selling the same
>old stuff, I guess. High-priced buckets for bottomless boats.
Then what is your job here? Giving impractical advice to turn people
off of solar?
>>>Now where can I buy that foam blanket system? UV-poly comes in big pieces,
>>>eg rolls 32' wide by 100' long that cost $160 and weigh 75 pounds, eg from
>>>Geiger at (800) 4GEIGER or ecgs...@hortnet.com or http://www.hortnet.com.
>>>It's easy to heat seal. Do you own an iron?
>Well?
>>Blue Sheild makes a foam blanket. You just shouldn't use it of the
>>pool during the day (because it's opaque). (1/8" of foam)
>An R-value of 1/2, if perfectly dry?
If we're lucky, R-1
>>It's easily rolled onto a conventional roller, but the foam does soak up water
>>after a while and gets rather heavy.
>Do you think that might somehow affect its insulation value?
It sure does, which is why I don't recommend them. Use a standard
bubble blanket, and an active solar pool heater to extend your season.
Don't bother to heat the pool if the air temperature is so cold that
you want to swim (unless you have an indoor pool).
Andy
No more Snarky comments
Nick Pine
Andrew McKegney <sun...@pathcom.com> wrote:
>>I wonder why most solar heating professionals completely ignore the
>>greenhouse industry, who have been working with inexpensive and practical
>>outdoor transparent structures for years. And vice versa...
Still wondering...
>>>The maintenance on such a system would be horrendous compared to a
>>>conventional solar pool heater.
>>I disagree. It might be less, with less plumbing and valves and so on.
>Nick you have already stated that the plastic would have to be
>replaced every 3 years. That's 400 % more maintenance (minimum) than a
>conventional solar system.
How do you figure that?
>Sometimes
>>it pays to take a fresh look at things, even when heating swimming pools...
>No doubt about that. But I would guess that 90% of inovation comes
>from people within an industry trying to find a more cost-effective
>way THAT WORKS.
Yup. Some of them can even spell.
>>>What about the roof itself?
>>Perhaps it would last longer, with the shingles all covered with plastic.
>No it won't. This is a known problem with solar systems. The roof must
>be allowed to dry out. (applicable to asphalt shingle tiles specifically)
I suspect that would not be a problem here. Overheating might be...
>>>Fastening clamps to a standard asphalt shingle roof
>>>and then two layers of poly and then supply piping...
>>Horrible thought, eh? ...the clamps might go on the sides of the house,
>>not screwed right flat on the roof. The upper layer of plastic would have to
>>be changed and recycled every 3 years or so, perhaps less often if it had
>>shadecloth over it in the summer (another useful greenhouse product, seldom
>>seen elsewhere, at 15 cents/ft^2, with an outdoor lifetime of 10 years (?))
>>Changing the poly film should take less than an hour, on a calm day, at a
>>cost of 5 cents/ft^2. Perhaps this thing should have one 2" PVC supply pipe.
>>Should the plastic be draped over the ridge pipe?
>Less than an hour to remove and reinstall hundreds of square feet of
>plastic on a roof.... what dream world are you living in? This is
>almost a full days job!!!!
Pends on how fast you work, and how conveniently the clamps are arranged.
CT Films has an ap note that says the labor cost to install poly film is
$0.02 per square foot. It also depends on how high the roof is, where
you keep your ladder, and the wind:
While most growers know the basic rule--"don't install film on a day
with wind"--there are always new faces in the business who might not
know. A 40' x 100' sheet of greenhouse film can turn into a sail
strong enough to drag several grown men across a field...
When installing double layers of sheet, one may, if there is a shortage
of labor, temporarily fasten the first layer at the corners and at
convenient intervals along the length; 15-20' intervals usually suffice.
The second sheet is then put in place so that both layers are superimposed.
Fastening is usually done at the ends first, then along the length or sides.
>>>What about water under the plastic rotting the roof...
>>Should the lower layer be EPDM rubber, which lasts forever...
>EPDM rubber is a lot more expensive than poly-plastic sheeting.
28 cents/ft^2 vs 5 cents, but it lasts forever.
>Boards & tires????? You've got to be kidding. Do you think people are
>going to want their roofs to look like garbage dumps????
Would you prefer old sneakers?
>Get real.
I might say the same to you, were I more normative.
>My point in replying to this thread was to illustrate that
>while it may be possible for a do-it-yourselfer to patch together a
>solar pool heating system from materials from "Home Depot", that
>system will take a great deal of TIME and effort, a good deal of
>skilled workmanship and not a small amount of money (if the system is
>designed to deliver the same amount of heat as a conventional solar system).
And if a pool heating professional were to work out a system like that, once?
> Andrew, where are _your_ R10 pool covers?
>>>There is no such cover that I know of, which is too bad.
>>How pro-active. You know where to buy the UV poly. Start with a hot tub, and
>>an $80 200 in^3/min 7 psi peak, 2 psi continuous duty Danner dynamaster (800)
>>893-4220 piston air pump, 110VAC at 0.66 Amps, or their 120 in^3/min 12VAC
>>version, or the $169 1.8 cfm 4-10 psi WP120 12VDC 7 Amp diaphram air pump
>>from Jade Mountain at (800) 442-1972, jade...@indra.com, feeding a large
>>airstone or screened well point filter? A 7x7' pool cover filled with 6" of
>>bubbles has a volume of about 25 ft^3, and 1 cfm will fill that in less than
>>a half-hour. If the bubbles last 2 hours, the pump would have to run about
>>20% of the time. Tiny bubbles have an expansion ratio of 200:1, which means
>>the soapy water container needs to hold about 0.125 ft^3 or 1 gallon of a
>>2% Green Dawn solution (?)
>>There's a hot tub air blower in the Grainger catalog, $193 for their 2P681
>>35 cfm at 115 VAC, 6.6 Amps. Yes, this is a bad habit, but maybe that blower
>>can also be used to inflate the bubble foam cover, somehow...
>As far as I can determine, you're talking about a spa cover here.
Pretty discerning :-)
>That's a far far cry from a full size pool. There are lots of R-10
>(and better) spa covers available. Pools are a much bigger problem.
But a spa might be a good place to start with a system like this.
>>A 24x32' pool cover filled with 6" of bubbles would have 384 ft^3 of volume,
>>requiring a 16 gallon soapy water container and a larger air pump, eg the $58
>>Grainger 4C442 140 cfm 0.95" blower, which uses 1 Amp at 110VAC. (This blower
>>is used to inflate 2 layers of plastic film on commercial greenhouses, 24
>>hours a day, to prevent wind fatigue. CT Film's rule of thumb is that 1/30
>>blower horsepower protects 10,000 ft^2 of poly pillow area, so this blower
>>should work for a greenhouse up to about 1 acre. Would it protect a rooftop
>>film pool heater, with a wind switch? Probably so.) A bubble foam pool cover
>>might be inflated by bubbles that come out of a 30 gallon plastic drum full
>>of soapy water buried in the ground, with a 2" hose from the blower, mounted
>>on top of the drum, disappearing down into the center of a 14" diameter
>>floating platform in the drum, supported by a floating ring, with a piece
>>of plastic window screen around the hose. The foam needs recycling somehow,
>>perhaps through a filter to separate it into water and air.
>This cover mighr be fine if you never intended to remove it.
Agreed, eg over an 8' wide x 32' long tank made with EPDM rubber draped
inside 4' haybale walls, along the north wall of a commercial plastic film
greenhouse with the poly film painted white on the north wall, as a large
solar water heater or fishpond or sewage treatment system.
>A major factor in the regular use of pool blanket is the ease of installing
>and removing the cover. Given that a 1/4 inch thick blanket that rolls
>easily onto a roller at the end of the pool is considered an inconvienence
>by most pool owners, I can imagine their reaction to the inflatable monstor
>you're proposing!
Yeah. "Let's just bomb Iraq to reduce my pool heating bill."
I was thinking it could be rolled up too, after the bubbles disappeared.
>>>insulation value of a cover is of little value if the cover is opaque.
>
>>What preposterous rubbish. Are your house walls transparent?
>
>Glass walls -what a new concept !<)
I'm not sure you have completely grasped the point here.
>The insulation value of a cover is of little value if the cover is opaque.
He said it again. Remarkable.
>The temperature of the ground averages 50 Degrees F. in my part of the
>world, and not much higher in most of the continental US.
About 55 F, where I live.
>50 degrees is way-cold for a swimming pool.
Agreed.
>82-85 degrees is where most pool owners would like to be.
Sounds good to me. That's what the little jet engine is for. To compress some
55 F air to raise the temp to 85, and return 25 F air to the ground, which
heats it up again, with a COP of 10 or 20....
>>And fer Chrissake some insulation around the sides of the pool.
>Sure let's install insulation under the existing 6,000,000 existing pools!
I'm not sure insulation under the pool is all that necessary, with some
solar heat and a good cover. Some people, eg ASHRAE, figure deep earth has
a temp equal to the average air temp, 55 F where I live, and an effective
R-value of 10. But perhaps we could slip some foamboard behind the liners
of existing pools, or retrofit them somehow, and build new pools differently.
>Duh!!! Little jet engine!!! Why not a little nuclear reactor!!
Most people don't like them, Andy. Except weirdos like Atomic Rod.
>Then you wouldn't create carbon dioxide while heating your pool!
I suppose you wouldn't do that using the sun, either.
>>>What a solar blanket really does is prevent water from evapourating
>>>from the pool. Most heat loss in a pool is from evapouration. Putting
>>>a blanket on the pool can reduce its' heat loss by 70%. (this make
>>>pools much easier to keep warm).
>>Duh^3. Most third-graders could figure that out.
>Yet, you consider this irrelavent.
No, just inadequate. Are you completely oblivious of spelling?
>>>What about the other 6,000,000 (conservative estimate) pools in the US?
>>Not my job. What are you doing about that, Andy? Just selling the same
>>old stuff, I guess. High-priced buckets for bottomless boats.
>Then what is your job here? Giving impractical advice to turn people
>off of solar?
I hope not. I'm not sure what my job is here. Spellchecker?
Bullshit detector? Educator? Better solution suggester?
>>>>Now where can I buy that foam blanket system? UV-poly comes in big pieces,
>>>>eg rolls 32' wide by 100' long that cost $160 and weigh 75 pounds, eg from
>>>>Geiger at (800) 4GEIGER or ecgs...@hortnet.com or http://www.hortnet.com.
>>>>It's easy to heat seal. Do you own an iron?
>>Well?
Well?
>>>Blue Sheild makes a foam blanket. You just shouldn't use it of the
>>>pool during the day (because it's opaque). (1/8" of foam)
>>An R-value of 1/2, if perfectly dry?
>If we're lucky, R-1
Probably not.
>>>It's easily rolled onto a conventional roller, but the foam does
>>>soak up water after a while and gets rather heavy.
>>Do you think that might somehow affect its insulation value?
>It sure does, which is why I don't recommend them.
OK.
>Use a standard bubble blanket, and an active solar pool heater
>to extend your season.
Hey, some plastic film on the roof!
>Don't bother to heat the pool if the air temperature is so cold that
>you want to swim (unless you have an indoor pool).
I'm having trouble parsing that. And understanding that. How cold is too cold?
I felt perfectly comfortable in an 98 F outdoor hotel pool in Banff, Alberta,
when the air temp was -12 F, at night, with snow falling on my head... It was
a too warm for swimming.
Nick
Andrew McKegney
ni...@ufo.ee.vill.edu (Nick Pine) wrote:
>Andrew McKegney <sun...@pathcom.com> wrote:
>
>>>I wonder why most solar heating professionals completely ignore the
>>>greenhouse industry, who have been working with inexpensive and practical
>>>outdoor transparent structures for years. And vice versa...
>Still wondering...
Because solar space heating is a con. It may be great for enthusiasts
who have more time and money and space and a great do-in-yourself
streek, but for the average homeowner, it is not cost effective or
practical. Thousands of solar air heating systems were sold when the
US had grants for them (10-20 years ago), but I would hazard a guess
that 99% of them were sold by hucksters who promptly went out of
business. Very few people have the space to install transparent
structures to heat their homes. You seem to have a particular fetish
about them. Are they "good" for you or what?
>>Don't bother to heat the pool if the air temperature is so cold that
>>you want to swim (unless you have an indoor pool).
>I'm having trouble parsing that. And understanding that. How cold is too cold?
>I felt perfectly comfortable in an 98 F outdoor hotel pool in Banff, Alberta,
>when the air temp was -12 F, at night, with snow falling on my head... It was
>a too warm for swimming.
I bet that pool was not heated by a solar system. Nor could it be
during the winter. A more likely renewable heat source would be a hot
spring, which I don't think Banff has.
It is clear to me that your purpose here is to tell people what they
"should" do rather than help them figure out what they can do. Not
only that, your advice always seems based upon your own particular
entrancement with plastic films.
Again, if you had to make a living selling, installing and maintaining
solar systems, you would think your own ideas to be folly.
If you want a solar system, and you want one that works without
requiring large amounts of maintenance, that you don't have to build
and install yourself, call a specialist in the field (call 2 or 3) and
get a quote on a manufactured solar product.
Andy McKegney C.E.T.
Nick Pine
Andrew McKegney <sun...@pathcom.com> wrote:
>>>>I wonder why most solar heating professionals completely ignore the
>>>>greenhouse industry, who have been working with inexpensive and practical
>>>>outdoor transparent structures for years. And vice versa...
>>Still wondering...
>Because solar space heating is a con.
Yes, there's been lots of that. It's time to fix that.
>It may be great for enthusiasts who have more time and money and space and
>a great do-in-yourself streek, but for the average homeowner, it is not
>cost effective or practical.
Agreed, as usually done, with rooftop panels, or direct gain houses
outside of the southwest. But that doesn't mean it has to be that way.
>Very few people have the space to install transparent structures to heat
>their homes.
Bullshit. Every house has a south or southwest or southeast wall or roof.
Altho some houses are more suitable than others.
>>I felt perfectly comfortable in an 98 F outdoor hotel pool in Banff, Alberta,
>>when the air temp was -12 F, at night, with snow falling on my head... It was
>>too warm for swimming.
Ice all over the steps and handrails, too...
>I bet that pool was not heated by a solar system. Nor could it be
>during the winter. A more likely renewable heat source would be a hot
>spring, which I don't think Banff has.
Can you say "Banff Springs Hotel" :-)
Nick
Dick Lambert
I missed the first posts on this subject but I gather that Andrew
McKegney was looking for some ideas on solar pool heating in a cold
climate. Will someone with a 12 year old solar pool heater in Minnesota
do? Minnesota - you know, the place where summer is two months of bad
skiing.
I put four 1000' coils of 1" black poly piping on my (admittedly flat)
garage roof. They are plumbed in parallel to keep the head loss low. A
small Grundfos pump, controlled by a $100 controller that senses
the temperature of the roof as well as the pool water,
circulates water through the system anytime the roof temperature
exceeds the pool water temp. It also will run the solar pump if the roof
temperature is below 40 to prevent freezing. I use a "bubble pack"
solar cover. I haven't had any maintenance expenses on the system in 12
years and it typically keeps the pool between 88 and 90 (the pump turns
off at 90) . It is able to bring the water up about 6 or 7 degrees per
sunny day if we have a long cool cloudy stretch. In short, the pool has
always been at a comfortable temperature anytime the outside was warm
enough for anyone to be interested in swimming. We typically open the
pool in late May and close it in early September.
--
Richard C. Lambert 800 Brenner Avenue
President Roseville, Mn 55113-1904
R.C. Lambert & Associates, Inc. (612) 483-1492
Energy Conservation Consulting Engr lamb...@gold.tc.umn.edu
dale
At last someone with real life experience!
I have been trying to do something like this in an area of
the world where black pipe of any kind does not exist
(northeast Poland). Whatever I want, I will have to import or
carry it in from a long ways off, so I want to get it right
at the start.
What is a grundfos pump?
How many gallons per minute are going through it?
Who makes the controler?
What exactly is black poly piping? 'Poly' what? Is it
flexible, is it resistant to decay from the sunlight and hot
water? How much total space does a 1000' coil take up. Is it
coiled tight or with space between the coils? Does it have
any covering (glazing, glass or plastic) over it, or
insulation under it? Would that make a significant
difference?
dale
Andrew McKegney
Dick Lambert <lamb...@gold.tc.umn.edu> wrote:
Dear Mr. Lambert
Thankyou for posting your experience. Actually it is a strong
supporting case for the "discussion" I have been having with Mr. Pine.
Your system which uses poly pipe sounds very typical of most
do-it-yourself systems -although larger by a factor of ten - which is
good! Many do-it-yourselfers will only install 100 - 300 feet of pipe
(not 4000 like you) and make the same claims about performance as you.
Unfortunately their systems aren't capable of heating that well.
(thermal physics raises it's practical head.!<)
The only caution I suggest about coils of pipe, is being sure to drain
them completely before freezing weather. Poly pipe is not made to be
exposed to the sun (it's designed to be buried) and as a result it
hardens after 2-3 years, and will split if it is frozen full of water.
On a flat roof it may not be too hard to blow the pipe out. On a
sloped roof, it is very hard to blow the water out of the bottom half
of the loops of coil.
PS. This thread went in this direction because I was recommending the
use of conventional, manufactured, solar pool heating panels.
Andrew McKegney
Sylvan Butler
black polyethylene
>flexible,
So-so. Won't do sharp bends, but does bend somewhat.
>is it resistant to decay from the sunlight and hot
Sunlight - not impervious, but resistant. Hot water? Somewhat.
>water? How much total space does a 1000' coil take up. Is it
A lot.
sdb
Hardison
syl...@cyberhighway.net (Sylvan Butler) wrote:
>dale (da...@xs4all.nl) wrote:
>>What exactly is black poly piping? 'Poly' what? Is it
>black polyethylene
>>flexible,
>So-so. Won't do sharp bends, but does bend somewhat.
Actually, the 0.6 mm black poly drip irrigation hose will almost make
a 1' diameter bend.. good for coiling flat.
>>is it resistant to decay from the sunlight and hot
>Sunlight - not impervious, but resistant. Hot water? Somewhat.
Sunlight? black drip irrigation hose lasts a long time right out in
the very hot sun. Over 5 years, I'm sure... from experience. In
fact, I can't remember ever seeing this stuff anything worse that a
little stiff after 10 years right out in the vey hot California
central valley sun. Pool chemicals? Maybe that's a problem. I don't
know yet.
>>water? How much total space does a 1000' coil take up. Is it
>A lot.
It isn't the space, it's the square feet of surface exposed to the
sun. A 500 foot coil donut is about 27 square feet- a 6 foot diameter
donut with a 1 foot diameter hole. A 1000 foot coil would be a little
over 8 feet in diameter. I have six 6-foot diameter coils for ease of
handling. Once a 6 foot dia. coil is hot melt glued every 6 inches or
so around the coil, you can pick it up by the middle and hoist it up
on the roof.
>sdb
Hardison
Dick Lambert <lamb...@gold.tc.umn.edu> wrote:
>
>I put four 1000' coils of 1" black poly piping on my (admittedly flat)
>garage roof. They are plumbed in parallel to keep the head loss low. A
>small Grundfos pump, controlled by a $100 controller that senses
>the temperature of the roof as well as the pool water,
I have the same set up (3000 FT) of coiled hose on my patio cover. I
just had a nice swim this evening in 84F water (so it works). But I
don't have a differential temperature controller like you describe.
I haven't seen any $100 controllers. Was that years ago? I need one
of those things! Please post a source!
S. Hardison>
Hardison
>The only caution I suggest about coils of pipe, is being sure to drain
>them completely before freezing weather. Poly pipe is not made to be
>exposed to the sun (it's designed to be buried)
I've used 1/2" black poly irrigation hose in the garden for 10 years
with nothing more serious than a little stiffness. It commonly sees 50
psi and lays in the sun year after year. I suspect this irrigation
hose will last a lot longer as a solar collector than you're supposing
here.
> and as a result it
>hardens after 2-3 years, and will split if it is frozen full of water.
This is probably true, but where you don't worry about hard freezes,
like here in the California central valley, a lot of black hose is a
viable solution for home-brew solar pool heating.
S. Hardison
Nick Pine
Hardison <SHar...@ix.netcom.com> wrote:
>I have the same set up (3000 FT) of coiled hose on my patio cover. I
>just had a nice swim this evening in 84F water (so it works). But I
>don't have a differential temperature controller like you describe.
>I haven't seen any $100 controllers. Was that years ago? I need one
>of those things! Please post a source!
The trade price of Heliotrope General's DTT '94 Combo was $74.80, including
sensors and a 110 VAC recepticle, as of 18 months ago. (800) 552-8838.
Nick
Nick Pine
Talked with Sven Tjernagel, who just got back from a trip. He says pool
chlorine should be no problem with EPDM rubber collectors, altho
roof pitch is, the way he builds them. He suggests no more than a 5:12
roof pitch, for an 8-10 year lifetime under two layers of glass. He imagines
that with no glass, the rubber should last 15 years or more. He sold these
things as a product for 9 years, along with their extrusions and hardware.
His collectors cost $9.30, including two layers of glass, etc, and the
largest ones are about 10' tall by 40' wide, limited by the size of the
sheet of rubber two people could carry. The Gettysburg Motel just rebuilt
their 1600 ft^2 of collectors on a new roof. Their accountant figures these
double-glazed units pay for themselves every 14 months, for domestic water
heating. That would shorten a lot for pool heaters, with no glazing or
EPDM rubber replacement.
Nick
Dick Lambert
At 08:50 AM 10/7/96 +0100, Da...@xs4all.nl wrote:
>>I missed the first posts on this subject but I gather that someone
>> was looking for some ideas on solar pool heating in a cold
>>climate. Will someone with a 12 year old solar pool heater in
>>Minnesota do? Minnesota - you know, the place where summer is two
>>months of bad skiing.
>>I put four 1000' coils of 1" black poly piping on my (admittedly flat)
>>garage roof. They are plumbed in parallel to keep the head loss low.
>>A small Grundfos pump, controlled by a $100 controller that senses
>>the temperature of the roof as well as the pool water,
>>circulates water through the system anytime the roof temperature
>>exceeds the pool water temp. It also will run the solar pump if the
>>roof temperature is below 40 to prevent freezing. I use a "bubble
>>pack" solar cover. I haven't had any maintenance expenses on the
>>system in 12 years and it typically keeps the pool between 88 and 90
>>(the pump turns off at 90) . It is able to bring the water up about 6
>>or 7 degrees per sunny day if we have a long cool cloudy stretch.
>>In short, the pool has always been at a comfortable temperature anytime
>>the outside was warm enough for anyone to be interested in swimming.
>>We typically open the pool in late May and close it in early September.
>>
>>Dick Lambert
>At last someone with real life experience!
>
>I have been trying to do something like this in an area of the world where
>black pipe of any kind does not exist (northeast Poland). Whatever I want,
>I will have to import or carry it in from a long ways off, so I want to get
>it right at the start.
>
>What is a grundfos pump?
Grundfos is a brand name of a pump - I believe the parent company is in
Germany. All I have is the US address: Grundfos Pumps Corp, 2555 Clovis
Avenue, Clovis, California 93612, USA (209) 292-8000. I'm using a 1/12
horsepower model #UP-26-96BF which has a bronze volute (case) and a
stainless steel impellor.
>How many gallons per minute are going through it?
I estimate that it's pumping about 9.5 gallons/minute.
>
>Who makes the controler?
Goldline Controls division of Independent Energy Inc., 42 Ladd Street,
East Greenwich, Rhode Island, USA (401) 884-6990, (800) 343-0826. I'm
using their model CM30 - X0102 which is a pool & spa unit with a 55 to
110 deg F adjustable maximum pool high limit ($80 in 1985). It uses a
model INS-1 insolation sensor ($10 in 1985) and a model SC-1/2 water
temperature sensor ($10 in 1985).
>
>What exactly is black poly piping? 'Poly' what?
Flexible high density polyethylene. I used a 1" 80 psi rated product
under the brand name of "Excel" made by Granse Corporation, 21670
Hamburg Avenue, Airlake Industrial Park, Lakeville, Minnesota 55044, USA
(612) 469-2191, (800) 328-4509. I paid $110.00 per 1000 foot coil in
1985. This type of pipe is connected with radiator hose clamps and
barbed fittings (male barbed fitting on both ends) which slip inside the
pipe thereby reducing its internal diameter. In addition to the time
and expense of making the connections, each fitting creates a high
pressure drop compared to the normal fittings used with rigid pipe. I
special ordered long length coils to minimize the problems, expense, and
pressure drop many connections would cause.
> Is it flexible?
Yes - see below.
>Is it resistant to decay from the sunlight and hot water?
Yes, the manufacturer claimed that they use a an "ultraviolet proof"
resin that does not deteriorate in sunlight. I have not seen any
deterioration in the pipe at all. In fact, I deliberately left the odd
lengths I had left over on the garage roof alongside the solar heater.
They have been left in the sun subject to everything the solar heater
piping has had to face except for the pool water inside. Therefore,
they have had a tougher environment since there was no water to carry
away the heat - they just baked in the sun. I just brought a piece
that's been on the roof since July 1985 down and it flexes just like it
was brand new - absolutely no sign of hardening or brittleness at all.
I just bent the piece into a 2 foot diameter circle with virtually no
noticeable flattening of the pipe - there was no flattening with a 3
foot diameter circle.
> How much total space does a 1000' coil take up? Is it coiled tight or with space between the coils?
I laid the pipe on an 85 deg F day in four flat spiral coils that
started at about 3 1/2 foot in diameter and went out to about 11 feet in
diameter. All four coils fit in an area of about 11 feet by 44 feet.
>Does it have any covering (glazing, glass or plastic) over it, or insulation under it?
No. I thought about glazing but decided it was [A] too expensive to do
it with low maintenance glazing like glass, [B] to maintenance prone
with a cheaper plastic, and [C] likely to damage the EPDM roofing below
the glazing if I had installed it. I took the lack of glazing into
account when I decided how much pipe to install. I don't think there
would be much of an efficiency gain from insulating beneath the array,
however, I decided that I would add some kind of closed cell (not porous
to water) insulation beneath to protect the roof membrane if I ever did
need to glaze to increase capacity.
> Would that [glazing] make a significant difference?
Most definitely, I would guess that glazing would at least double the
efficiency. As it stands now I benchmarked my system as follows: On
5/21/94 at 1:35 PM central standard time with no clouds and a 90 deg F
outside air temperature the solar heater delivered a 13 deg F
temperature rise (77 deg entering pool water temperature, and 90 deg F
leaving pool water temperature). I got essentially the same results a
month later. The temperature rise goes up due to the increased delta T
when the pool water is colder.
Hope this helps.
----
Dick Lambert
Hardison wrote:
>
> Dick Lambert <lamb...@gold.tc.umn.edu> wrote:
>
> >
> >I put four 1000' coils of 1" black poly piping on my (admittedly flat)
> >garage roof. They are plumbed in parallel to keep the head loss low. A
> >small Grundfos pump, controlled by a $100 controller that senses
> >the temperature of the roof as well as the pool water,
>
> just had a nice swim this evening in 84F water (so it works). But I
> don't have a differential temperature controller like you describe.
> I haven't seen any $100 controllers. Was that years ago? I need one
> of those things! Please post a source!
>
Goldline Controls division of Independent Energy Inc., 42 Ladd Street,
East Greenwich, Rhode Island, USA (401) 884-6990, (800) 343-0826. I'm
using their model CM30 - X0102 which is a pool & spa unit with a 55 to
110 deg F adjustable maximum pool high limit ($80 in 1985). It uses a
model INS-1 insolation sensor ($10 in 1985) and a model SC-1/2 water
temperature sensor ($10 in 1985).
--
Dick Lambert
> >McKegney was looking for some ideas on solar pool heating in a cold
> >climate. Will someone with a 12 year old solar pool heater in Minnesota
> >do? Minnesota - you know, the place where summer is two months of bad
> >skiing.
>
> >garage roof. They are plumbed in parallel to keep the head loss low. A
> >small Grundfos pump, controlled by a $100 controller that senses
> >the temperature of the roof as well as the pool water,
> >exceeds the pool water temp. It also will run the solar pump if the roof
> >temperature is below 40 to prevent freezing. I use a "bubble pack"
> >solar cover. I haven't had any maintenance expenses on the system in 12
> >years and it typically keeps the pool between 88 and 90 (the pump turns
> >off at 90) . It is able to bring the water up about 6 or 7 degrees per
> >sunny day if we have a long cool cloudy stretch. In short, the pool has
> >always been at a comfortable temperature anytime the outside was warm
> >enough for anyone to be interested in swimming. We typically open the
> >pool in late May and close it in early September.
>
>
>
> Thankyou for posting your experience. Actually it is a strong
> supporting case for the "discussion" I have been having with Mr. Pine.
>
> Your system which uses poly pipe sounds very typical of most
> do-it-yourself systems -although larger by a factor of ten - which is
> good! Many do-it-yourselfers will only install 100 - 300 feet of pipe
> (not 4000 like you) and make the same claims about performance as you.
> Unfortunately their systems aren't capable of heating that well.
> (thermal physics raises it's practical head.!<)
>
> them completely before freezing weather. Poly pipe is not made to be
> hardens after 2-3 years, and will split if it is frozen full of water.
> sloped roof, it is very hard to blow the water out of the bottom half
> of the loops of coil.
The manufacturer (Granse) claimed that they use a an "ultraviolet proof"
resin that does not deteriorate in sunlight. I have not seen any
deterioration in the pipe at all. In fact, I deliberately left the odd
lengths I had left over on the garage roof alongside the solar heater.
They have been left in the sun subject to everything the solar heater
piping has had to face except for the pool water inside. Therefore,
they have had a tougher environment since there was no water to carry
away the heat - they just baked in the sun. I just brought a piece
that's been on the roof since July 1985 down and it flexes just like it
was brand new - absolutely no sign of hardening or brittleness at all.
I just bent the piece into a 2 foot diameter circle with virtually no
noticeable flattening of the pipe - there was no flattening with a 3
foot diameter circle.
BUT, if the coils were mounted in anything but a horizontal surface they
would have to be blown out well. I used to have the same outfit that
blew out my underground sprinklers blow out my solar heater too until
they blew UP my $80 multiport pool valve - then I started doing it
myself with a small 3/4 hp compressor. The sprinkler outfit used a
trailer mounted compressor of the type used for jackhammers and it blew
the system dry (and no it did not unwind my solar coil like a New Years
eve part favor).
John Harrison
Dick Lambert <lamb...@gold.tc.umn.edu> wrote:
>I missed the first posts on this subject but I gather that Andrew
>McKegney was looking for some ideas on solar pool heating in a cold
>climate. Will someone with a 12 year old solar pool heater in Minnesota
>do? Minnesota - you know, the place where summer is two months of bad
>skiing.
>I put four 1000' coils of 1" black poly piping on my (admittedly flat)
>garage roof. They are plumbed in parallel to keep the head loss low. A
>small Grundfos pump, controlled by a $100 controller that senses
>the temperature of the roof as well as the pool water,
>circulates water through the system anytime the roof temperature
>exceeds the pool water temp. It also will run the solar pump if the roof
>temperature is below 40 to prevent freezing. I use a "bubble pack"
>solar cover. I haven't had any maintenance expenses on the system in 12
>years and it typically keeps the pool between 88 and 90 (the pump turns
>off at 90) . It is able to bring the water up about 6 or 7 degrees per
>sunny day if we have a long cool cloudy stretch. In short, the pool has
>always been at a comfortable temperature anytime the outside was warm
>enough for anyone to be interested in swimming. We typically open the
>pool in late May and close it in early September.
Befoe this topic dies - can you tell me how putting the pipes in
parallel "keeps the head loss low"?
I am thinking of doing this deal, and I need to know the best way to
get the water from my 3" pool pipes up onto the roof which is some
distance away (say 25 feet horizontal ) and up to the roof (say 15-20
feet above the filter pump).
There will be a fair resistance (??) as the pipe narrows to the black
poly pipe diameter - will my filter pump (1.5hp) handle the pressure
load from the height as well as the resistance from the smaller tube ?
What "valves" need to be put in this system?
Andrew McKegney
John.H...@mailbox.uq.oz.au (John Harrison) wrote:
>Dick Lambert <lamb...@gold.tc.umn.edu> wrote:
96:10:17
Dear John
There are a couple of ways to keep the head loss low. The most
efficient is to use several (many) coils in parallel (each coil being
supplied (and returned to) by a common pipe) rather than one big coil
with one inlet and outlet. The supply and return lines must be a least
the same size as your regular plumbing -- or -- a second less
desirable method of reducing pressure drop -- substancially reduce the
flow rate of the water through the piping, which will also allow you
to use smaller diameter piping.
Note: the principle of using multiple parallel paths is used in almost
all commercial solar pool panels. They typically have dozens (if not
hundreds) of parallel tubes per panel. This is why they have such low
pressure drops while handling all of the flow from the pool filter.
Note 2: To collect the most heat from any solar panel, you want it to
operate as cool as possible. The warmer it is, the more heat it loses
to the air around it. So you want to push as much water as you can
through the panels to keep their temperature down. This will be a
problem if you have only one continuous coil as the pressure drop
through it will be very high, and this will seriously reduce the flow
rate through your filter.
To solve the problem of high pressure drop in a single coil system you
can install a diverter valve in the pool plumbing (between the supply
and return lines of the solar system) and open in to allow some water
to bypas the solar system and go staight back to the pool.
BTW all solar plumbing should be on the line returning to the pool,
after the filter (this keeps the crap out of the solar panels).
A third way to reduce the "effect" of the pressure drop from a solar
system on a pool pump is to use a seperate pump to circulate the water
throught the solar panels. This does involve the additional expenses
of the pump and the operation of the pump (and perhaps a seperate
timer/controller).
To answer your question as to whether or not you 1.5 hp pump could
"handle the pressure", it will work but pump much less water. The
result is you will likely get insufficient filtering to keep your pool
clean. A well installed commercial system might see a 4 psi pressure
drop between solar on & off. A single coil system could easily see a
20 psi pressure drop.
Another point to mention about pressure drops, is that in closed
systems (not open to the air) the height of the solar panels is not a
factor (except when first filling the system) because the weight of
the column of water going up equals the weight of the column of water
coming down. If the system is "open" with a vacuum breaker or other
method the column of water going up is not offset by the water coming
back.
Andrew McKegney C.E.T.
Guy Macon
Expanding on a point in Andrew's excellent post;
In article <545pu7$7...@news.pathcom.com>, sun...@pathcom.com (Andrew McKegney) says:
>
>Another point to mention about pressure drops, is that in closed
>systems (not open to the air) the height of the solar panels is not a
>factor (except when first filling the system) because the weight of
>the column of water going up equals the weight of the column of water
>coming down. If the system is "open" with a vacuum breaker or other
>method the column of water going up is not offset by the water coming
>back.
>
This is 100% true in any reasonable solar pool heater, but there is an
exception that the industrial folks migh run into...
The weight of the column of water going down only offsets the first
11 meters or so of the column of water going up. Past that, a
partial vacuum forms in the line going down. This assumes 1
atmosphere at the outlet. A pressurized loop can go higher and
still have a full syphon effect.
The real problem is when you expect the water going down to cool
something. The partial vacuum (water vapour, really) does not
cool the pipe walls as well as water would...
Dick Lambert
John Harrison wrote:
>
> Dick Lambert <lamb...@gold.tc.umn.edu> wrote:
>
> >I missed the first posts on this subject but I gather that Andrew
> >McKegney was looking for some ideas on solar pool heating in a cold
> >climate. Will someone with a 12 year old solar pool heater in Minnesota
> >do? Minnesota - you know, the place where summer is two months of bad
> >skiing.
>
> >I put four 1000' coils of 1" black poly piping on my (admittedly flat)
> >garage roof. They are plumbed in parallel to keep the head loss low. A
> >small Grundfos pump, controlled by a $100 controller that senses
> >the temperature of the roof as well as the pool water,
> >circulates water through the system anytime the roof temperature
> >exceeds the pool water temp. It also will run the solar pump if the roof
> >temperature is below 40 to prevent freezing. I use a "bubble pack"
> >solar cover. I haven't had any maintenance expenses on the system in 12
> >years and it typically keeps the pool between 88 and 90 (the pump turns
> >off at 90) . It is able to bring the water up about 6 or 7 degrees per
> >sunny day if we have a long cool cloudy stretch. In short, the pool has
> >always been at a comfortable temperature anytime the outside was warm
> >enough for anyone to be interested in swimming. We typically open the
> >pool in late May and close it in early September.
>
> Befoe this topic dies - can you tell me how putting the pipes in
> parallel "keeps the head loss low"?
A pump only pushes so much water through a given resistance so if you
put four 1000' pipes in parallel you'll have 1/4 of the resistance of
4000' in series.
> I am thinking of doing this deal, and I need to know the best way to
> get the water from my 3" pool pipes up onto the roof which is some
> distance away (say 25 feet horizontal ) and up to the roof (say 15-20
> feet above the filter pump).
> There will be a fair resistance (??) as the pipe narrows to the black
> poly pipe diameter - will my filter pump (1.5hp) handle the pressure
> load from the height as well as the resistance from the smaller tube ?
No. I used a separate Grundfos brand circulating pump that taps into my
2" pool line just after the filter and returns the heated water on the
other side of an elbow - it isn't meant to run without the main pool
pump running. I've got about a 10' rise to the garage roof. I
recommend that you run as large a pipe to the roof as practical to keep
losses down.
> What "valves" need to be put in this system?
I would suggest six. One one each of the four 1000' coils to aid in
blowing them out (assuming your in an area that freezes) plus two more
to isolate the heater from the main pool circulating line is case you
solar system develops a leak.
--
Dick Lambert 800 Brenner Avenue
John Harrison
Dick Lambert <lamb...@gold.tc.umn.edu> wrote:
amongst other stuff
>No. I used a separate Grundfos brand circulating pump that taps into my
>2" pool line just after the filter and returns the heated water on the
>other side of an elbow - it isn't meant to run without the main pool
>pump running. I've got about a 10' rise to the garage roof. I
>recommend that you run as large a pipe to the roof as practical to keep
>losses down.
>> What "valves" need to be put in this system?
>I would suggest six. One one each of the four 1000' coils to aid in
>blowing them out (assuming your in an area that freezes) plus two more
>to isolate the heater from the main pool circulating line is case you
>solar system develops a leak.
I am not in an area that EVER freezes, but I thought that I would need
a valve at the pump end to prevent " backflushing " from the water up
on the roof when the pump goes off, and also some other sort of valve
to stop the down pipe (outlet) from the solar collector from
collapsing from negative pressure when the pump goes off (won't the
water in this pipe just run down into the pool otherwise?).
Excuse my ignorance - I know nothing about solar, pressure, flow,
valves etc!!!
What sort of valves are we talking about????
Dick Lambert
John Harrison wrote:
>
> Dick Lambert <lamb...@gold.tc.umn.edu> wrote:
>
> amongst other stuff
>
> >No. I used a separate Grundfos brand circulating pump that taps into my
> >2" pool line just after the filter and returns the heated water on the
> >other side of an elbow - it isn't meant to run without the main pool
> >pump running. I've got about a 10' rise to the garage roof. I
> >recommend that you run as large a pipe to the roof as practical to keep
> >losses down.
>
> >> What "valves" need to be put in this system?
>
> >I would suggest six. One one each of the four 1000' coils to aid in
> >blowing them out (assuming your in an area that freezes) plus two more
> >to isolate the heater from the main pool circulating line is case you
> >solar system develops a leak.
>
> I am not in an area that EVER freezes,
Then you wouldn't really need the individual valves on the four parallel
coils. I'd still recommend the two isolating valves at the pool pump in
case the system developes a leak you shut it off without having to turn
off your main pool pump.
>but I thought that I would need
> a valve at the pump end to prevent " backflushing " from the water up
> on the roof when the pump goes off
This isn't a problem unless you have a leak in the pipe above that opens
the system to the atmosphere.
> and also some other sort of valve
> to stop the down pipe (outlet) from the solar collector from
> collapsing from negative pressure when the pump goes off
This isn't a problem
(won't the
> water in this pipe just run down into the pool otherwise?).
See above
> Excuse my ignorance - I know nothing about solar, pressure, flow,
> valves etc!!! What sort of valves are we talking about????
I'd suggest what's know as a ball valve - they are available from any
decent do-it-yourself store. Get one that has a full sized port, i.e.,
the hole thru the rotating ball should be the same size as the pipe the
valve it for.
kri...@micron.net
Dick Lambert <lamb...@gold.tc.umn.edu> wrote:
>John Harrison wrote:
>>
>> Dick Lambert <lamb...@gold.tc.umn.edu> wrote:
>>
>No. I used a separate Grundfos brand circulating pump that taps into my
>2" pool line just after the filter and returns the heated water on the
>other side of an elbow - it isn't meant to run without the main pool
>pump running. I've got about a 10' rise to the garage roof. I
>recommend that you run as large a pipe to the roof as practical to keep
>losses down.
>> What "valves" need to be put in this system?
>I would suggest six. One one each of the four 1000' coils to aid in
>blowing them out (assuming your in an area that freezes) plus two more
>to isolate the heater from the main pool circulating line is case you
>solar system develops a leak.
>--
>Dick Lambert 800 Brenner Avenue
>President Roseville, Mn 55113-1904
>R.C. Lambert & Associates, Inc. (612) 483-1492
>Energy Conservation Consulting Engr lamb...@gold.tc.umn.edu
Could this type of system be converted to warm a house?
Is there any way to use a pond in the winter to heat a house?
Andrew McKegney
John.H...@mailbox.uq.oz.au (John Harrison) wrote:
>I am not in an area that EVER freezes, but I thought that I would need
>a valve at the pump end to prevent " backflushing " from the water up
>on the roof when the pump goes off, and also some other sort of valve
>to stop the down pipe (outlet) from the solar collector from
>collapsing from negative pressure when the pump goes off (won't the
>water in this pipe just run down into the pool otherwise?).
>Excuse my ignorance - I know nothing about solar, pressure, flow,
>valves etc!!!
>What sort of valves are we talking about????
The valve you are speaking of is a "check-valve" or "foot valve"(if at
the end of a pipe) They are designed to allow water to flow in only
one direction- ie: not drain out or back. They are available from any
plumbing store, or if you want PVC, a good pool service
store/department.
You will have a problem, if your system plumbing is "closed" meaning
not open to the air (anywhere), with a vacuum/negative pressure in the
plumbing at the highest point when the pump is off.
The solar industry uses vacuum breakers to allow air into the plumbing
if a negative pressure develops in the panels. This prevents plastic
panels, softened in high heat - non-operating conditions, from
collapsing. (and these products are designed to be in the sun - unlike
most poly pipe!)
Again, vacuum breakers can be purchased from a good plumbing store.
Shut off valves should be used on the supply and return lines as
noted by others.
Andy McKegney C.E.T.
John Harrison
I am still reading this with interest, but remember I live in brisbane
, Australia where it NEVER freezes!
I am pretty sure I am gonna try this setup with the poly pipes!
A couple of questions remain....
The pool pump (1.5HP) will have to lift the water to the roof (about
20ft) - will it have enough or too much pressure for a 1000 ft run of
polypiping? I am going to try one coil initially to see how i go. Can
I use the plastic securers (that you get in the garden/ hardware
shops)over the pipe barbed interconnectors or should I use metal
clamps?
What difference does it make to the system if there is gate or ball
valve somewhere after the pump but before the solar collector?
These restrict the diameter of whatever pipe they are put on. What
does it do to pressure vs flow??? Are they really necessary?
Won't the pump be struggling against this restriction since it has a
fixed output rate??? Does this harm the pump?
But better than blowing all the joins (not that there will be too
many) and having water all over my roof!
(My currnet pump runs from 40-100 psi depending on how dirty the
filter is!)
Does it really make any difference (to pressure, flow etc)where I make
the first join from the pvc 50mm PVC pipe (from the pump outlet) to
the 19mm black poly pipe.
A restriction is a resriction !!!
It is a lot easier for me to do this join at ground level near the
pump and then run the black poly up to the roof coil and back to the
pool. It is a lot harder (i.e. more work and money) to run the 50mm
pvc pipe up onto the roof and then make the connection to the coil. If
that makes a big difference to efficiency etc can someone tell me how?
johnsm...@maildrop.cc
> I missed the first posts on this subject but I gather that Andrew
> McKegney was looking for some ideas on solar pool heating in a cold
> climate. Will someone with a 12 year old solar pool heater in Minnesota
> do? Minnesota - you know, the place where summer is two months of bad
> skiing.
>
> I put four 1000' coils of 1" black poly piping on my (admittedly flat)
> garage roof. They are plumbed in parallel to keep the head loss low. A
> small Grundfos pump, controlled by a $100 controller that senses
> the temperature of the roof as well as the pool water,
> circulates water through the system anytime the roof temperature
> exceeds the pool water temp. It also will run the solar pump if the roof
> temperature is below 40 to prevent freezing. I use a "bubble pack"
> solar cover. I haven't had any maintenance expenses on the system in 12
> years and it typically keeps the pool between 88 and 90 (the pump turns
> off at 90) . It is able to bring the water up about 6 or 7 degrees per
> sunny day if we have a long cool cloudy stretch. In short, the pool has
> always been at a comfortable temperature anytime the outside was warm
> enough for anyone to be interested in swimming. We typically open the
> pool in late May and close it in early September.
>
>
> Richard C. Lambert 800 Brenner Avenue
> R.C. Lambert & Associates, Inc. (612) 483-1492
> Energy Conservation Consulting Engr lamb...@gold.tc.umn.edu