Question:

We had an solar heating panel for pool automatic pool cover, which caused the temp to be 10 – 20F warmer than neighbors pools,solar heating panel for pool used signficantly less chemicals and was much cleaner from blowing dust and trash.  Only bad part is we live in Phoenix,solar heating panel for pool and 105F in the summer is a little hot, but we could swim 9 months of the year.

Those inexpensive floating fountains powered by filter pumps could cool and oxygenate unchlorinated pool water to keep it biologically cleaner solar heating panel for pool. If I remember the thermodynamics, 75% of heat loss is evaporation, 10% was conduction, and the rest was ?solar heating panel for pool??

That only leaves convection and radiation… solar heating panel for pool, do you have any analytical data?

ASHRAE says a square foot of uncovered pool (or a wet hand) loses about 100(Pw-Pa) Btu/h, (about a 10th of a pound of water per hour) where Pw is the (saturated) water vapor pressure near the pool surface, which depends on temperature, and Pa is the atmospheric vapor pressure, which doesn’t directly depend on temperature. They ignore air temperature, ground temperature, windspeed, everything but evaporation, to estimate heat loss. Pw = exp(17.8623-9621(Tw+460)) “Hg at pool water temp Tw (F), roughly, and Pa = 29.921/(1+0.62198/w), where w is the atmospheric humidity ratio, ie the number of pounds of water per pound of dry air. NREL says the average air temp in July in Phoenix is 93.5 F. The average yearly (deep ground) temp is 72.6. The July humidity ratio w = 0.0105, so Pa = 0.497 “Hg; 2410 Btu/day of sun falls on 1 ft^2 of unshaded pool, so we might expect the pool temp to rise until 2410 = 24hx100(Pw-0.497), ie Pw = 1.5″ Hg, ie the pool water temp Tw = 91.1 F on an average July day. Less wind and more sun and humidity would raise the pool temp…solar heating panel for pool

Response:

Nick, you’re impressive as usual.solar heating panel for pool  Nominal non aerating temp is 90-92, about 85 w/ the sprayers on.  One advantage of the pool cover was the significantly lower chemical consumption.  On the other hand, near 0 evaporation  meant temps well above 91.1F, sometimes unbearable.. Best, Mike B only 6 weeks and counting until ‘nice’ temps… – Hide quoted text — Show quoted text – We had an automatic pool cover, which caused the temp to be 10 – 20F warmer than neighbors pools, used signficantly less chemicals and was much cleaner from blowing dust and trash.  Only bad part is we live in Phoenix, and 105F in the summer is a little hot, but we could swim 9 months of the year. Those inexpensive floating fountains powered by filter pumps could cool and oxygenate unchlorinated pool water to keep it biologically cleaner. If I remember the thermodynamics, 75% of heat loss is evaporation, 10% was conduction, and the rest was ??? That only leaves convection and radiation..solar heating panel for pool do you have any analytical data? ASHRAE says a square foot of uncovered pool (or a wet hand) loses about 100(Pw-Pa) Btu/h, (about a 10th of a pound of water per hour) where Pw is the (saturated) water vapor pressure near the pool surface, which depends on temperature, and Pa is the atmospheric vapor pressure, which doesn’t directly depend on temperature. They ignore air temperature, ground temperature, windspeed, everything but evaporation, to estimate heat loss. Pw = exp(17.8623-9621(Tw+460)) “Hg at pool water temp Tw (F), roughly, and Pa = 29.921/(1+0.62198/w), where w is the atmospheric humidity ratio, ie the number of pounds of water per pound of dry air. NREL says the average air temp in July in Phoenix is 93.5 F. The average yearly (deep ground) temp is 72.6. The July humidity ratio w = 0.0105, so Pa = 0.497 “Hg; 2410 Btu/day of sun falls on 1 ft^2 of unshaded pool, so we might expect the pool temp to rise until 2410 = 24hx100(Pw-0.497), ie Pw = 1.5″ Hg, ie the pool water temp Tw = 91.1 F on an average July day. Less wind and more sun and humidity would raise the pool temp..solar heating panel for pool

Response:

Nick, you’re impressive as usual.

Aw, shucks. One advantage of the pool cover was the significantly lower chemical consumption.

You might get by with aeration alone, like a sewage treatment plant. Some pools use hydrogen peroxide with a few silver and copper ions from floating PV-powered sources. only 6 weeks and counting until ‘nice’ temps…

You might shade the pool with a metal bow greenhouse over the top, partially covered with shadecloth on the south side.solar heating panel for pool.. NREL says the average air temp in July in Phoenix is 93.5 F. The average yearly (deep ground) temp is 72.6. The July humidity ratio w = 0.0105, so Pa = 0.497 “Hg; 2410 Btu/day of sun falls on 1 ft^2 of unshaded pool, so we might expect the pool temp to rise until 2410 = 24hx100(Pw-0.497).solar heating panel for pool..

With no sun at all, Pw = 0.497 = exp(17.863-9621/(Tw+460)), so Tw = 58.3 F. Nick

Response:

Can anyone provide information on using solar power to heat water in a swimming pool

Response:

most definitely check out http://www.warmwater.com/ & http://www.webconx.com/thermal.htm — — Steve Spence Subscribe to the Renewable Energy Newsletter: http://www.webconx.com/subscribe.htm Renewable Energy Pages – http://www.webconx.com Palm Pilot Pages – http://www.webconx.com/palm X10 Home Automation – http://www.webconx.com/x10 (212) 894-3704 x3154 – voicemail/fax We do not inherit the earth from our ancestors, we borrow it from our children. –

Can anyone provide information on using solar power to heat water in a swimming pool

Response:

Forget the solar arrays and expensive schemes.  The 75%+ is if you eliminate evaporation, you’ll get more thermal gain than any other reasonably priced alternative. We had an automatic pool cover, which caused the temp to be 10 – 20F warmer than neighbors pools, used signficantly less chemicals and was much cleaner from blowing dust and trash.  Only bad part is we live in Phoenix,solar heating panel for pool and 105F in the summer is a little hot, but we could swim 9 months of the year. Neighbors with a manual float on cover had similar results. If I remember the thermodynamics, 75% of heat loss is evaporation, 10% was conduction, and the rest was ??? If you’re not in the southwest, spend the $100 and swim longer. Nick Pine, do you have any analytical data? Best,   most definitely check out http://www.warmwater.com/ & http://www.webconx.com/thermal.htm — — Steve Spence Subscribe to the Renewable Energy Newsletter: http://www.webconx.com/subscribe.htm Renewable Energy Pages – http://www.webconx.com Palm Pilot Pages – http://www.webconx.com/palm X10 Home Automation – http://www.webconx.com/x10 (212) 894-3704 x3154 – voicemail/fax We do not inherit the earth from our ancestors, we borrow it from our children. — Can anyone provide information on using solar power to heat water in a swimming pool

Response:

I bought a solar heating panel from www.intheswim.com and absolutely LOVE it!  During the course of solar heating panel for pool a full sunny day the pool temp. has literally gone from 76 degrees to 84 degrees (American measurements)! There is no extra power, powered by the sun the panel uses the existing pump to push the water through the panel then into the pool. Works absolutely GREAT! Can anyone provide information on using solar power to heat water in a swimming pool

Response:

Question:

…As we live in So. California, almost all of our gas usage is for hot water.solar water heater tank repairs solar water heater tank repairs   We have plenty of sunshine, although not a lot of place to put solar panels, except on the roof of the garage…

Suppose you live in LA, where 890 Btu/ft^2 of sun per day falls on a horizontal surface in January, and 1300 falls on a south wall and I guess sqrt(890^2+1300^2) = 1575 Btu falls on a surface tilted up 90-atan(890/1300) = 56 degrees to the south. The 24-hour average temp is 56.8 F, with a 65.7 daily max, about 61 F during daylight hours, and a 23 F record low. The annual average (wellwater?) temp is 63 F. As there is no freeze here,solar water heater tank repairs  a direct system should suffice, without the need for a heat exchanger.

But maybe a pump and a hot water storage tank.solar water heater tank repairs  It seems to me that most solar hot water systems are undersized. I wonder how I might quantify the thermal output of a solar panel. I’d like to equate it to “therms,” so I might get some idea of the cost benefit of this,solar water heater tank repairs  before taking the plungesolar water heater tank repairs.

A square foot of solar heating panel with an R1 single cover with 90% solar transmission and 130 F water inside might gather 0.9×1575 = 1418 Btu of sun and lose about 6h(130F-61F)1ft^2/R1 = 413 on an average day, for an average net gain of 1005, so you’d need about 100 ft^2 of panels to make a therm of hot water per day, heating 100000/(8(130-63)) = 187 gallons of 63 F water to 130. You might use an unpressurized insulated 7′ diameter x 5′ tall 1500 gallon $400 ag poly tank to store hot water for a cloudy week, along with a $75 12V Shurflo RV pump with built-in pressure switch for the tank output. For the collectors, you might make something like this with a horizontal water-filled EPDM rubber bladder and Nielsen’s Mylar, $0.09/ft^2 in 4′ wide rolls from http://www.snomo.com/mylar.html…    The most serious mistake was making the outer container of the receiver    of plywood. We thought that the plywood would be sufficiently insulated    from the copper panel which was the receiver proper, that it would not    get too hot. The copper panel was separated from the plywood by 4″ of    fiberglass insulation.solar water heater tank repairs  Nevertheless, solar water heater tank repairs

Response:

This is very encouraging…

Do you have the Btu-ft^2 figures for, say, July? Suppose you live in LA, where 890 Btu/ft^2 of sun per day falls on a horizontal surface in January, and 1300 falls on a south wall and I guess sqrt(890^2+1300^2) = 1575 Btu falls on a surface tilted up 90-atan(890/1300) = 56 degrees to the south.solar water heater tank repairs  The 24-hour average temp is 56.8 F, with a 65.7 daily max, about 61 F during daylight hours, and a 23 F record low.solar water heater tank repairs  The annual average (wellwater?) temp is 63 F.

It’s going to take me a while to digest the numbers, and I am truly grateful for your excellent analysis. I think you mean one hundred square feet, not one hundred feet on a side (i.e., 10K square feet), right? A square foot of solar heating panel with an R1 single cover with 90% solar transmission and 130 F water inside might gather 0.9×1575 = 1418 Btu of sun and lose about 6h(130F-61F)1ft^2/R1 = 413 on an average day, for an average net gain of 1005, so you’d need about 100 ft^2 of panels to make a therm of hot water per day, heating 100000/(8(130-63)) = 187 gallons of 63 F water to 130. You might use an unpressurized insulated 7′ diameter x 5′ tall 1500 gallon $400 ag poly tank to store hot water for a cloudy week,solar water heater tank repairs  along with a $75 12V Shurflo RV pump with built-in pressure switch for the tank output. solar water heater tank repairs

I’m considering purchasing three 4′ x 10′ panels, new, mfg by Sun-Earth.solar water heater tank repairs  This would be about $3K.  Can I make something that compares to a manufactured product in terms of heat collecting ability? I am contemplating a system where I can manually adjust the tilt of the panels with a chain block and pulley.solar water heater tank repairs   Thus I could optimize for each month. I would have to use flexible copper tubing, coiled (and insulated, of course) to absorb the torsion in the hook up, to both top and bottom of the panels.  My fear is that the panels aren’t designed for this, and the fittings in side the panels might crack.  Have you ever heard of this or considered doing it?solar water heater tank repairs For the collectors, solar water heater tank repairs

Excellent tip regarding “success story” below!  Thank you.    The most serious mistake was making the outer container of the receiver    of plywood. We thought that the plywood would be sufficiently insulated    from the copper panel which was the receiver proper, that it would not    get too hot. The copper panel was separated from the plywood by 4″ of    fiberglass insulation. Nevertheless, the plywood caught fire and the unit    was completely destroyed.solar water heater tank repairs We suppose this is a success, of sorts…    fsolar water heater tank repairs

Response:

This is very encouraging…

Good… Do you have the Btu-ft^2 figures for, say, July? Suppose you live in LA, where 890 Btu/ft^2 of sun per day falls on a horizontal surface in January, and 1300 falls on a south wall and I guess sqrt(890^2+1300^2) = 1575 Btu falls on a surface tilted up 90-atan(890/1300) = 56 degrees to the south. The 24-hour average temp is 56.8 F, with a 65.7 daily max, about 61 F during daylight hours, and a 23 F record low. The annual average (wellwater?) temp is 63 F.

July has 2260 Btu/ft^2 on a horizontal surface and 770 on a south wall and a 24-hour average temp of 69.1 and a 75.3 average daily max. I think you mean one hundred square feet, not one hundred feet on a side (i.e., 10K square feet), solar water heater tank repairs

Right. I’m considering purchasing three 4′ x 10′ panels,solar water heater tank repairs  new, mfg by Sun-Earth. This would be about $3K.  Can I make something that compares to a manufactured product in terms of heat collecting ability?

Sure… I am contemplating a system where I can manually adjust the tilt of the panels with a chain block and pulley.  Thus I could optimize for each month. I would have to use flexible copper tubing, coiled (and insulated, of course) to absorb the torsion in the hook up, to both top and bottom of the panels.  My fear is that the panels aren’t designed for this, and the fittings in side the panels might crack.  Have you ever heard of this or considered doing it?

It could be done;solar water heater tank repairs  most people pick a single tilt or use flexible hoses.solar water heater tank repairs

Response:

Thanks again. Very encouraging… July has 2260 Btu/ft^2 on a horizontal surface and 770 on a south wall and a 24-hour average temp of 69.1 and a 75.3 average daily max.

Flexible hoses…that sounds like a great idea.  Get high quality hoses, insulate them, and swap them out every few years. On the other hand, they’ll be under pressure 24 hours a day,solar water heater tank repairs  all year long. Should I look into a hose that’s designed for “100% duty”? In the world of electric motors, there are those that are designed for intermittent duty, and those that are designed for continuous duty… Regards, solar water heater tank repairs  I am contemplating a system where I can manually adjust the tilt of the panels with a chain block and pulley.  Thus I could optimize for each month. I would have to use flexible copper tubing, coiled (and insulated, of course) to absorb the torsion in the hook up, to both top and bottom of the panels.  My fear is that the panels aren’t designed for this, and the fittings in side the panels might crack.  Have you ever heard of this or considered doing it? It could be done; most people pick a single tilt or use flexible hoses.solar water heater tank repairs

Response:

I am contemplating a system where I can manually adjust the tilt of the panels with a chain block and pulley.  Thus I could optimize for each month. I would have to use flexible copper tubing, coiled (and insulated, of course) to absorb the torsion in the hook up, to both top and bottom of the panels.solar water heater tank repairs   My fear is that the panels aren’t designed for this, and the fittings in side the panels might crack.  Have you ever heard of this or considered doing itsolar water heater tank repairs?

I doubt the variable pitch will be worth the expense, for a couple of reasons.  First, you lose very little if your panels aren’t perfectly perpendicular to the sun at midday.  sine(90) is 1.0,  but sine(80) is .984 and sine(70) is .94, so by being off axis 20 degrees you’ve lost only 6%. Second, assuming a fairly level year-round demand for hot water, it’s only in the winter months that you need to capture all the heat you can.  Summertime you’re getting more heat than you can use.  So, I suggest angling your panels to optimize for the coldest three months. Disclaimer: not an authority; ready to be enlightened by someone who is.

Response:

-solar water heater tank repairs  I am contemplating a system where I can manually adjust the tilt of the panels with a chain block and pulley.solar water heater tank repairs  Thus I could optimize for each month. I would have to use flexible copper tubing, coiled (and insulated, of course) to absorb the torsion in the hook up, to both top and bottom of the panels.  My fear is that the panels aren’t designed for this, and the fittings in side the panels might crack.  Have you ever heard of this or considered doing it? John I doubt the variable pitch will be worth the expense, for a couple of reasons.  First, you lose very little if your panels aren’t perfectly perpendicular to the sun at midday.  sine(90) is 1.0,  but sine(80) is .984 and sine(70) is .94, so by being off axis 20 degrees you’ve lost only 6%. Second, assuming a fairly level year-round demand for hot water, it’s only in the winter months that you need to capture all the heat you can. Summertime you’re getting more heat than you can use.  So, I suggest angling your panels to optimize for the coldest three months.solar water heater tank repairs  Disclaimer: not an authority; ready to be enlightened by someone who is.

You’ve got a point there.solar water heater tank repairs   Here’s another point…if my wife will let me put the panels on the garage roof (where they are very visible from the front of the house) they will keep my garage cooler in the summer.  That’s a reason to tip them back.  However,solar water heater tank repairs  the roof has a pitch of just over 20 degrees, so that isn’t the 9 degrees that is perfect for noon on June 21 anyway.

Response:

…if my wife will let me put the panels on the garage roof (where they are very visible from the front of the house) they will keep my garage cooler in the summer.solar water heater tank repairs  That’s a reason to tip them back.  However, the roof has a pitch of just over 20 degrees…

You might paint the south roof white and stand the panels up vertically on the peak… solar water heater tank repairs

Response:

…assuming a fairly level year-round demand for hot water, it’s only in the winter months that you need to capture all the heat you can. Summertime you’re getting more heat than you can use.solar water heater tank repairs  So, I suggest angling your panels to optimize for the coldest three months.

A reflective surface or snow on the ground might add 30%…solar water heater tank repairs

Response:

I have wondered if reflective surfaces that could be put in place during the winter would be worth it. In CO the panels were 2′ above the ground and I noticed an increase when the first snows came.solar water heater tank repairs  Wish I had better monitors back then. dw – Hide quoted text — Show quoted text – …assuming a fairly level year-round demand for hot water, it’s only in the winter months that you need to capture all the heat you can. Summertime you’re getting more heat than you can use.  So, I suggest angling your panels to optimize for the coldest three months. A reflective surface or snow on the ground might add 30%…solar water heater tank repairs

Response:

I’m considering purchasing three 4′ x 10′ panels, new, mfg by Sun-Earth. This would be about $3K.

Seems high if it’s just for the panels.solar water heater tank repairs You might try this outfit.solar water heater tank repairs

Question:

What is the cheapest Solar Panel Inverter heating possible way for producing large parabolic mirrors for solar thermal power plants? How high is the cost at present? Would it be possible to produce ultra-cheap mirrors by means of solar energy itself? I mean, to build first one “mother” power plant with large parabolic mirrors and using it for melting glass out of desert sand (and other needed materials), then turning that glass into mirrors by adding an aluminium layer. And then to use these new mirrors for building new power plants nearby (or use these new mirrors for expanding the area of original power plant). Or would it be more simple to use some other material than glass for mirrors? Solar Panel Inverter heating For example, just melting desert sand for smooth, parabolic “stone mirrors” and covering them with aluminium and some protective layer (like SiO2)? Or is there some other really cheap material that could be used? Basically, if really ultra-cheap mirrors could be produced, would it not then be possible to cover (at least in theory) really large desert areas with solar thermal power plants? By the way, plants use somewhat similar principle successfully. They exploit solar energy and local materials, and soon large areas are covered with these little “power plants”.

Response:

Perhaps mirror reflective mylar, either 5 or 10 mil, mounted to a curved surface.

Solar Panel Inverter heatingWhat is the cheapest possible way for producing large parabolic mirrors for solar thermal power plants? How high is the cost at present? Would it be possible to produce ultra-cheap mirrors by means of solar energy itself? I mean, to build first one “mother” power plant with large parabolic mirrors and using it for melting glass out of desert sand (and other needed materials), then turning that glass into mirrors by adding an aluminium layer. And then to use these new mirrors for building new power plants nearby (or use these new mirrors for expanding the area of original power plant). Or would it be more simple to use some other material than glass for mirrors? For example, just melting desert sand for smooth, parabolic “stone mirrors” and covering them with aluminium and some protective layer (like SiO2)? Or is there some other really cheap material that could be used? Basically, if really ultra-cheap mirrors could be produced, would it not then be possible to cover (at least in theory) really large desert areas with solar thermal power plants? By the way, plants use somewhat similar principle successfully. Solar Panel Inverter heating They exploit solar energy and local materials, and soon large areas are covered with these little “power plants”.

Response:

What is the cheapest possible way for producing large parabolic mirrors for solar thermal power plants? How high is the cost at present? Would it be possible to produce ultra-cheap mirrors by means of solar energy itself? I mean, to build first one “mother” power plant with large parabolic mirrors and using it for melting glass out of desert sand (and other needed materials), then turning that glass into mirrors by adding an aluminium layer. And then to use these new mirrors for building new power plants nearby (or use these new mirrors for expanding the area of original power plant). Solar Panel Inverter heating

Reflective mylar is one that’s cheap, but it needs a surface and degrades pretty quick. Or would it be more simple to use some other material than glass for mirrors? For example, just melting desert sand for smooth, parabolic “stone mirrors” and covering them with aluminium and some protective layer (like SiO2)? Or is there some other really cheap material that could be used?

A novel way is to collect as many mirrors as you can possibly get, broken, large, small, Solar Panel Inverter heating who cares as long as it’s bright and shiney. Now take these and mount them all over the area of interest so that the suns reflection will track a certain area. Remember that the mirrors will be fixed so the receiver will need to move, play around with this. An acre of mirrors pointed to a raised collector that can move (or a collector ring, oval, whatever a black pipe of the right width that is fixed.) to collect all the energy or even more collectors, you can of course do the math and see how much energy can be gotten. Solar Panel Inverter heating