Free heat! (well almost, gotta run the fan)

Originally Posted by jghilino

you could put a solar panel on the roof and then run a 12 volt fan off of it and a 12 volt pump to circulate the coolant?

You could run a pump or fan in a variety of ways. You have to do the math. You would need a battery of some size to regulate the voltage.

For example, one of the fans I put a link to was 2.5 amps. You can very inexpensively get a solar panel that puts out 2.5 amps, but as soon as a cloud passes by you will no longer be getting 2.5 amps, which obviously affects the fan (not enough juice to run). This would happen all day and most likely burn out the fan (or pump). A simple, cheap, 5ah battery solves this problem.

I personally would want a bigger battery, it would seem that a 10ah battery would be a better choice as it will run the fan for 4 hours unassisted by the solar panel.

What would end up happening is that you will use a little of the juice from the battery from time to time, but it would quickly charge in the morning when the heater hasn't reached a high enough temp to cut the fan on but there is sunlight.