pigpen;
Not sure what type of panels you're talking about. Solar panels maybe since you write about cells. If so then, no, you wouldn't want to put any type of liquid there will do a couple things.
Lower ability for sunshine to wade through
ruin cells as the fluid migrates into cells:-((
If these are Solar panels for heating assistance then the working fluid should be something that would be freeze/ heat resistant. Mineral oil is a good choice , but a bit expenesive. Glycol is a better choic with respect the freezeing and cost but thermal transfreance isn't as good as Mineral oil would be , plus most glycol mixes are poison.
There is another possibility of gathering the watse glycerin from some close who is homebrewing biodiesel ,but this you would need to make sure is at least 75% cleaned up from the methanol, if you go this route , use the heat of the summer to help boil the methanol out of the glycerin , then run a titrate to find if there is any menthaonl left.
Back to solar panels::: If these are indeed PV type panels it would better to cool the backside of the panels by way of moving air to move the heat.
Do you have any pics you get show, we can help further.
Cheers
Bruce s
