[Piwoslaw]

Originally Posted by elhigh

what if I got a small window-mount heat pump unit, detached its exterior coil and built a water box around that?

What if you did that with your fridge? That's been floating around in my head for a while. If you already have some kind of ground source piping in the house, then sticking the refrigerator's coils into that would not only raise its efficiency (as would external insulation), but would also add some extra heat to the source of your heat pump. In fact, you can go one step further and notice that the temperature inside the fridge is close to either the temperature of your ground source, or of the return, so why not put the whole fridge in a water jacket? No compressors, no coils, no noise.

I've also been wondering about how much heat can be stored underground? Say you dump your A/C heat into the ground during the summer. How much of it will still be there when you need it in the winter, and how much will dissipate? That probably depends on your climate. Here, heating season is 5-7 months, while A/C might be needed no more than 2-6 weeks. Say you have solar panels that help with heating or hot water, but which are too big for summer. Would it be worth while to pump the sun's heat into the ground all summer?