Can you have too many solar heating panels???

[BBBliever]

Just installed an 80 sq ft solar panel for my 160 sq ft pool. I'm very happy with the results and performance. The rack I built for the panel was the largest expense in the project. The panel is on 4x4's, 2x4's and hardibacker board. It is elevated about 9 feet and at a 45 degree angle. I have room to place another panel at a 20 degree angle below the first. Expense would be minimal to add on to the structure of the rack. For less than $300 I can get the panel and build the rack to hold it.

Is 160 sq ft of solar panels way overkill for 160 sq ft of pool? Would 2 panels keep the water warmer longer or just make the water hotter for the same time frame? I'm thinking when it turns to 3 or 4 hours of direct sun for the panel two panles would double the heat output.

Am I right or would a second panel just be a waste of money. When the weather turns will it be futile to try to heat the pool with solar regardless of the amount of solar panels?

 

[JasonLion]

Additional panel area will increase the portion of the year that the water will remain warm enough to swim in. Of course not everyone is interested in swimming when the air temperature is very cold, regardless of the water temperature.

Overheating is not an issue, since the system can be run at night to cool the pool should over heating be a risk.

 

[BBBliever]

Thank you Jason. You confirmed my thoughts. With another panel I will be swimming for Thanksgiving for sure. Winters are mild in my location of California. Only a few nights during the winter will temps drop to around 30. In the middle of winter average high temp would be in the low 50's with night time temps dropping to upper 30's. With my hot tub the pool will get winter use.

 

[mas985]

I have about 80% of my pool surface area in solar panels and there are a few days in November/March where the panels can produce quite a bit of heat but it really depends on average air temperature. If the average air temp is too low, then the panel efficiency drops off dramatically and it is hard to get a large temperature rise. But that is ok with me since I rarely want to swim when the air temp is low anyway.

 

[FloridaSolarPro]

Am I right or would a second panel just be a waste of money. When the weather turns will it be futile to try to heat the pool with solar regardless of the amount of solar panels?

It depends on where you are located to some extent. In Southwest Florida, 100% coverage (panel area equals pool surface area) will give you about 10 degrees over the Gulf temperature depending on your panel's BTU rating. Once you exceed 100% coverage, the marginal efficiency decreases rapidly. In any case, increasing your coverage to 160 square feet would be advisable to extend your swimming season.

 

[chem geek]

It depends on where you are located to some extent. In Southwest Florida, 100% coverage (panel area equals pool surface area) will give you about 10 degrees over the Gulf temperature depending on your panel's BTU rating. Once you exceed 100% coverage, the marginal efficiency decreases rapidly. In any case, increasing your coverage to 160 square feet would be advisable to extend your swimming season.

You must be talking about an uncovered pool that loses a lot of heat at night. When using a pool cover, one can expect a lot higher temperature gain from solar. I have 11 4' x 10' FAFCO SunSaver and 1 4' x 8' FAFCO Revolution panels for 466.1 sq. ft. of effective surface area. The pool is 15.5x32 feet so 496 sq. ft. for a ratio of 94% though 2 of the panels are often shaded by a tree. This post shows the average day/night temps where I live which is close the the temperature of pool water with no heating nor cover. I can get the water temp to be 20ºF higher April, September and October and 25ºF higher in May, June, July and August when using a relatively thin mostly opaque electric safety cover. When using a more insulating bubble-type cover, one can get even higher net (retained) heat gain.