Reply #38: I like your heat storage idea

[txlibdem]

While I don't understand how it would tie in with photovoltaic panels, I think you are onto something. I could see it working well with solar thermal to store heat (or cold) in a heat store like a gravel pit. I've also heard of a sand pit with a closed loop of pipes from the energy source, and another closed loop of pipe that go to the inside of the house to take the heat from the sand (or to dump the heat from the inside).

I would suppose that in the summer the energy source would be underground pipes since the temperature at 4ft or 6ft depth is always around 50 or 60 degrees depending on your latitude, or (if you're lucky enough to be near water) a lake, pond, or river. And in the winter the energy source would be a solar hot water unit that you could build for probably less than $100 if you're even a little bit handy.