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solar heating swimming pool water

Joe Miranda

Titanium
Joined
Oct 19, 2004
Location
Elyria Ohio
Have any of you come up with a way to harness solar energy to heat your swimming pool? We live in the northern Ohio area and we could sure get a lot more use out of the pool if we could warm it up about 10 degrees. I hate the thought of investing several thousand dollars for a gas water heater. Any suggestions?

Joe Miranda
 
Retard evaporation and add solar gain: Float a piece of 4 mil black visqueen on the water and keep the water circulating. Remove the plastic to use the pool. At night cover the pool with something insulating (another sheet of visqueen?)to hold the heat. It'll take a week to get to 80 degrees water temp but once you're there it's easy to hold.


The thing to remember is that evaporation removes lots of heat from the water. Also the black plastic will keeps algae from forming and keeps the leaves and bugs out of the water. Pool covers are a Good Thing.
 
There are commercial panals that you plumb in line with your filter to do this. Check with some of the larger mail order pool supply places. They are fairly cheap. If you are not already using a solar cover everytime the pool is not used, do so. It will also reduce the chemical demand of the pool as well.
 
Agreed with Forests comments. I started a pool project last August and filled it about 2 months ago. I covered it when ambient temps were around 50 degrees and water temp was 51 degrees.

After a week of intermittant sun it heated up to 65 degrees - now about 2 months later after the last week of a couple of warm sunny days and now a few rainy days with partial sun it bounces around between 75 and as high as 82 degrees.

My next experiment is the coils of black pipe laid out on the roof.

Eventually, I'd like to see if I can use the water in a heat exchanger with my heat pump to lower my A/C costs in August - does anybody have any idea if something is available to switch in/out in place of the standard outdoor heatpump unit?
 
I have a six panel solar array on my patio roof. I'm on the eastern California high desert with lots of sunshine and mild weather. From March thru May and again from Sept thru mid Movember I can keep the pool water between 78-82 with no problem. June, July, and August I can shut it down. 4'x 12' panels cost about $200 each. The surface area of your array should be no less than 3/4 of the surface area of your pool. If you do a solar array I suggest you design your system to use a separate pump than your filter pump. The filter pump is just over kill and you end up diverting 60-70% of the pump output and wasting a lot of electricity. Each panel requires only 5 GPM at 50 PSI Max. For my array I use a small pump rated 30GPM at 35 PSI. The pump pulls about 1.5 Amps. Can run it as long as needed very economically. While the initial cost of the array will be close to the cost of a large gas heater, the cost to operate is minimal. Do a Google search for solar pool heaters and you will find a wealth of info.
 
Joe,

I stayed in a mom and pop motel once that used a coil of black plastic water pipe like the 1" stuff you use for a water well. It was coiled up on top of a dark colored roof. They diverted some of pumps output through the black pipe and into the pool. Looks to me that it would work pretty good. Cheap too!

Troy
 
Swimming pool supply dealers stock various sizes of floating insulators. These are large blankets of "bubble-pack" material that float on the pool surface.

They do a fair job of allowing sunlight to radiate through the translucent material during daylight hours while retarding convection losses (due to the trapped air in the bubbles) at night.

Unhappily, these things are fairly expensive and need to be replaced every four or five years due to gradual deterioration from ultraviolet exposure and pool chemicals.
 
I do use a solar cover and it does a fairly good job of keeping the heat in when the temperatures during the day are fairly hot (@85-90F). But when the temperature dips below that we have never been successful in keeping the water temperature much above 70-72F. If I could get the water to about 80F we would be thrilled. I like the idea of pumping the water through black plastic pipe plumbed over the roof somehow.

Joe
 
Solar panels are the way to go. My brother scored some used ones and put them on the roof of the garage which was near the pool.

Use a child-proof cover if there are ever toddlers at your house. A child can fall in the pool and not be seen under a floating cover. I don't know the fencing requirements in Ohio, but if fenced, use gates that a child can't open.

I grew up cleaning pools for my father's pool service company. Any poolman's biggest fear is walking in to service a pool and finding a child drowned. Far too many children die needlessly every year in swimming pools and spas.

Les
 
A Saftey Pool cover is the first step. Not cheap but the piece of mind is worth it. Does a great job of heating the pool during the "season". I sometimes have to leave it open at night in August to let it cool down.

I have for years made "plans" to try some of the solar options described above. So far I've always had a "hotter" project, but I would very much like to hear how you come out. Solar could get me several more months of use out of the "Money Pit".
 
My neighbors from a good while ago built some solar collectors for heating the pool. He let the normal filter pump circulate the water. Make sure and put an automatic bypass to not pump through the collectors at night. It would easily keep the pool in the 80's even when it was in the 30's outside.

If you are so inclined you can also run a line into the house and build a heat exchanger to pre-heat the water going to your hot water heater. If you want to do that, run the output from the solar collectors through the heat exchanger first. Build as much collector surface area as you can get away with.
 
I live in the UK but I have a small swimming pool in Menorca, in the Balearics. It's long way to walk for a swim.

This Visqueen stuff?? Forrest I can get 600 grade black builder's polythene sheeting over there.
We only use the place about three fortnights a years and do not really want to fit solar panels which may be damaged in the winter storms. Our neighbours' stuff was damaged.

Would this builders stuff left on the bottom of the pool while it is not used, improve matters?

It would be all be fished out prior to the pool being used.

Norman
 
Ken, a water source heat pump can be used for cooling only applications and tied into a swimming pool as the water source. It will heat your pool while it cools your house, and the electricity usage on a WSHP will be about half what it is on a standard air to air split system. They're typically a single unit roughly the size of a residential gas furnace. I changed out a brand new wshp in a bank several years ago where an idiot had run a sheetmetal screw thru the refrigerant piping while installing ductwork. The unit lost its charge prior to ever being started, and the low pressure switch kept it from ever being run. The unit served a breakroom/conference room area and the back side of the ATM(lots of heat from those critters for some reason), and the bank simply wanted the unit removed and a new wall hung Japanese split system installed, so I brought the unit back to the shop and repaired the leak, charged it up and found that it was fine. My sister has a pool, but didnt have A/C, so we put it in her house. House is about 1800 sq ft, and built in the early 60's so it definitely isnt super-insulated. Running the unit added about $35/month to their usual power bill, with power at about 7.5 cents/Kw. We cut the pool piping on the discharge side of the pump and added a pair of tees with isolation valves, plus a bypass with another balancing valve such that we could create a restriction in the line but yet not force the entire flow of the pool pump thru the unit. One thing that's vital when using a pool as the water source is to install a flow switch in the water line and interlock the control power circuit of the unit thru the flow switch. With any water cooled A/C unit it is essential to shut off the compressor in the event of low or absent water flow, because during the cooling cycle the water temp in the condenser will go sky high in a heartbeat, and during the heating cycle where the condenser is now cooling the water by extracting heat from it, a lack of flow will freeze the water in the condenser in a matter of a couple minutes, and smash the refrigerant lines within the vessel as the ice expands. The units themselves are compact and simple, so the equipment cost per ton is actually less than for an air to air system. If you have any questions on this now or in the future, feel free to fire away
 
When I built pools 30 years ago, I set up a couple of systems where we simply ran a 100 foot coil of cheap black PE tubing[1 inch] on a handy roof with a couple of Ts and shut offs. worked great even in northern NY
 
I saw a wonderful solar heating system here in the UK a few years ago.
Take about 2000 dark glass
champagne bottles, remove the contents, knock a hole in the conical recess in the bottom, thread like beads on a couple of thousand feet of garden hose, make up a wooden armature and coil the bottle/hose around - tipi shape seems to work. Connect to your water pump and Bob's your uncle!
Takes a while to empty the bottles - but what a party!
 
About twelve years ago I installed a solar heating system in a pool. The buildings nearby, a garage and a pool house, had aluminum roofs. I attached copper lines to the inside surfaces of the roof, going in the parallel direction of the studs. All was fed uphill to a central pipe going along the top of the ridge board. Feed was supplied by a Bell and Gossett SLC-25 circulator pump. I had a bleed line at the top of the ridge to drain the system. You just opened a valve on the wall and air was introduced to the top. In one minute everything was drained for freezing weather. Closing the valve and turning on the pump reloaded the system. I had a jog button installed to force maximum pump output. I only had 18 feet of head and it took all it had to push the bubbles from the system. A thermal differential was installed to vary the pump speed. After sundown the unit would shut off.

The setup for Appalachia was almost too good. The water in the pool was vary warm for most of the season. In October they were still swimming with only solar heat. It more than doubled the swimming season for this area.

Truth be told; I also installed a ten section National solid fuel boiler in the garage, the next year. I installed a dual heat exchanger setup for domestic water and one to heat the pool. The boiler heated the garage, house, barn, and the remaining waste heat was shunted into the pool. After this the solar unit only was used when the boiler was down. This meant it was only used from May through September, from then on.

The solar system had the added affect of lowering the temperature in the buildings. It is amazing how much cooler a building is when the roof is cooled. The water evaporation got extreme. Warm water in cool dry weather blows away like someone punched a hole in the bottom of the pool.
 
Yes one idea. Use the discharge side from your pump to supply water flow. My dad built this year's ago. Build a rectangular box about 8 to 10 inches deep. Length and width about the size of a glass sliding door. That will be the cover. Painting the inside flat black. Now using plastic pipe. Make a surpenine out of pipe get as many feet as possible. The more feet the longer the water is in the hot box. Paint everything black. Hook up the discharge side to the pool . Hope this helped. It did for him.
 








 
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