panel manufacturers all provide a wealth of information on their panels' performance.
From the temperature characteristics you can work out the magnitude of improvement that would be produced.
If you produce a 10°C reduction in cell temperature (approx an 18°F at the temperatures we are considering) with say liquid cooling
, which I think would be achievable if you crunch the numbers, you come up with about a 3-5% gain.
You have to consider the draw of the pump. Typically this might be 1A or so for a small pump. The solar
array would therefore have to be producing around 25A to break even.
From these numbers, I cannot see a way to significantly improve solar panel efficiency with liquid cooling
, at least not without a passive system that would circulate the water
with little or no energy. Even then, the gains are small for the complication involved. I would love to be proved wrong, as more solar output would be great.
The goal of producing "free" hot water
where the gain in solar panel production runs a pump which creates warm water for showering, is a more realistic one. Even if there was a net loss of power, the warm water would be helpful.
Note: leaving an air gap for passive air cooling is important. This of costs no power and without this there is a danger
the Vmp can drop below the battery
voltage in some circumstances with 12v panels
. If this happens the power output will drop dramatically.