Home made water cooling system

[jtsi73]

Hi,
I'm a newbee to PV and I found the MJLorton Youtube vids after purchasing my system and building this cooling system(wish I'd watched them before, great stuff!). I have polychrystaline panels and altough Finland is a cold country we have had a few days when the temperature on the roof and panels went over the 60 degrees C mark. I witnessed a drop in amperes of almost 35%, so I built a cooling system of parts I had lying around: An old drainage pump and some old water hose, I utilised my roofs guttering and the barrel we collect rainwater in for watering the garden. It works like this: the pump pumps the rainwater trough the hose to the upper part of the panels, where the hose is fixed with (at the moment) some ironwire to the frames existing holes. I made slits with a knife along the hose so that the water covers the panels, the gutter then takes the water back to the barrel. I have meassured a drop of 30 degrees C, when the temperature in the shade is 27 C. This brings my PV current back to full power, the old pump takes 200VA, the gain in power is about 500W (not exact measurements, I rely on my chargers logs for this info). The water temperature will reach up to 40 C after a while, but the convection still keeps the temperature just under 40 C, one helping factor might also be that I painted my steel roof white round and under the panels (this brings down the temperature from 60 to 40, on the roof, not panels). I use this system on a 15 min timer (15min on 15 min off, I had the timer lying around also) during the hot days hottest hours. Only drawback is that is sounds like its raining .

My Q are: Is this widely used? If not, why? Are there some known drawbacks I should be aware of?

[SeanB]

Major reason is that the constant water flow accelerates the corrosion of the panel mountings and frames, and this will shorten panel life a lot when water penetrates through to the interconnects or the silicon inside. You will have to look carefully at the panels and correct corrosion there, as well as most likely paint the frame steelwork with a corrosion inhibiting paint in addition to the existing coating, you will see rust forming on cut and punched edges most likely. As well you need to ensure the panel edges are well sealed, and there are no water dams forming on the bottom of the panels, though with the high elevation likely with your panels this is not likely. The backs though will be exposed so they will need extra protection from dripping water.