I just has solar heating installed to my roof. 8 4x12 panels and 2 inch pvc. It is going up to my roof which is pretty high up. 25-30 feet. Yesterday was 88 and sunny in so ca and my pool was 86. The water coming out of the jets did not feel any warmer than pool. Should I feel a difference coming out of jets? The pool also didn’t get any warmer. Could this be due to too much pressure?
New solar heater
- Thread starter Jravenstine
- Start date
- May 3, 2007
- 18,067
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
You actually don't want much temperature difference between the inlet and out of the panels. Less than 5F rise is normal operation. But also, the temperature difference is proportional to the flow rate through the panels. Ideally, the panels should have about 40 GPM which should produce around 4F rise in the heat of the day. If there is twice the flow rate, the rise will be half as much.
But wouldn't you be heating twice as much water?
Not being a smartie pants. Genuinely asking!
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Desert Dog
Silver Supporter
I feel a difference in mine. Since it is new, is it automated? Do you know what temp the system is set too? The pool may already be at it's target temp and turned off flow to the panels (If automated). Mine is set to 88 degrees and according to ScreenLogic, it is only diverting water in the morning to the panels for three hours to hit the target. From the rest of the day the sun/heat has been holding it there. a month ago when it was cooler out, the panels had water diverted to them the whole day.
- May 3, 2007
- 18,067
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Correct, that is why the net heat transfer is theoretically the same in both situations. My only point was that you can't judge the performance of a solar panel by measuring only the heat rise.
However, heat loss is another matter. The larger the heat rise in the panels, the more heat is lost to the evironment.
Desert Dog
Silver Supporter
But wouldn't you be heating twice and much water?
Hard to explain. At least for me. When the water is traveling through the pipes, it can only reach a certain temp because your heat source is the sun. Push water too fast and it does not reach that temp. Too slow and you are wasting time. Lets say you can warm 50 gallons a minute, but are only warming 25 because your flow rate is slow. Too fast and it doesn't get to it's target temp. Make any sense?
Hard to explain. At least for me. When the water is traveling through the pipes, it can only reach a certain temp because your heat source is the sun. Push water too fast and it does not reach that temp. Too slow and you are wasting time. Lets say you can warm 50 gallons a minute, but are only warming 25 because your flow rate is slow. Too fast and it doesn't get to it's target temp. Make any sense?
It is not automated but I am thinking about getting a automated controller so I can see temperature going in and coming out. So far I don’t see how it will get hot enough to ever turn off.
Desert Dog
Silver Supporter
Not sure if you can get automation to show in and out temps. I'll I've seen is one temp sensor for water temp. Are your panels facing south? Guessing they are Swim Joy panels? Our temps are roughly the same. I'm more inland than you and probably get a little more sun. I have 6 4X12 panels and they work great. Just trying to guess why you don't feel a difference. Maybe the pool water is just too close to what the system can produce so your not feeling it and you will in cooler months. What temp are you trying to achieve?
Maybe put a thermometer in the water and then in front of a return to see if you register a difference. In cooler months it can take the panels a couple of days just to raise 4 degrees. They work, but just not miracles.
Maybe put a thermometer in the water and then in front of a return to see if you register a difference. In cooler months it can take the panels a couple of days just to raise 4 degrees. They work, but just not miracles.
- May 3, 2007
- 18,067
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
@Jravenstine, what is the pump RPM while running solar? What is the filter pressure with and without solar enabled? What is the pool temperature in the morning and evening?
Is your signature correct in that you have a 11,500 sq-ft pool? That is huge. Or did you mean to say it is 11,500 gallons and the spa is 500 gallons.
Is your signature correct in that you have a 11,500 sq-ft pool? That is huge. Or did you mean to say it is 11,500 gallons and the spa is 500 gallons.
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Desert Dog
Silver Supporter
Mark (mas985),
I see you recommended above a flow rate of 40 GPM. My solar installer told me they recommend running a flow rate of 7 gallons per minute per panel for 4x12 Swim Joy Panels. I have mine for 6 panels set to 45 GPM. Does this sound correct? Would this mean Jravenstine should run his at 60 GPM (or what ever RPM that equals) since he has 8 panels?
I see you recommended above a flow rate of 40 GPM. My solar installer told me they recommend running a flow rate of 7 gallons per minute per panel for 4x12 Swim Joy Panels. I have mine for 6 panels set to 45 GPM. Does this sound correct? Would this mean Jravenstine should run his at 60 GPM (or what ever RPM that equals) since he has 8 panels?
- May 3, 2007
- 18,067
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Most manufactures recommend 0.1 GPM/sq-ft. or about 5 GPM for a 4x12 panel. 30 GPM for 6 panels and 40 GPM for 8 panels. Lower than that and efficiency starts to drop off. Higher than that and efficiency doesn't improve much.
Here is a typical efficiency curve:
Here is a typical efficiency curve:
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