Geothermal Heat

I'm wondering whether capturing summer heat (very hot where I live right now) in an underground tank of water would make the heat available in wintertime. Assuming the ground is quite dry with a known uniform temperature, how can I calculate the heat dissipation rate to determine how long the water would stay warm?
- Ward Webber (age 67)
Hines, OR, USA

Yes, it certainly does work. You don't even need the water tank! A couple of meters below the surface in ordinary soil the temperature is nearly constant over the year, because heat diffuses slowly through the soil. So if you drill down and put some pipes to carry heat to that deep soil, you have a source for heat in the winter and a sink for heat in the summer. You can get these geothermal wells drilled even for established houses. My colleague Scott Willenbrock had some put in his house (see  ) and there are several others around my neighborhood. They do a great job of saving energy. It doesn't make sense, given the problems with our energy sources, not to use these geothermal systems much more.

Mike W.

(published on 07/03/2015)