Tapping the Earth For Home Heating and Cooling

suraj.sun recommends a CNet post giving details of a still little-known energy technology: the ground source heat pump or geo-exchange system. This is distinct from so-called geothermal energy, which taps the heat in the earth to provide energy. Geo-exchange is suitable in scale for small industry — the article describes one commercial re-development of an old mill into apartment and commercial space that put in a geo-exchange at about half the cost of traditional fossil fuel-based alternatives. Even some individual homeowners are opting for this green method of heating and cooling, at a premium in price of about 50 percent (but costs are very much per-project, largely because drilling is involved). "Rather than use underground heat, geothermal heat pumps attached to buildings capitalize on the steady temperature of the ground or deep water wells. In effect, they treat the Earth like a giant energy savings bank, depositing or withdrawing heat depending on the time of year. "

Comments

"little known" ???

[Gothmolly]

Ah yes, kdawson.

This technology is HARDLY little-known, but places where people need lots of heating and cooling (the Northeast) are also places where electricity is uber expensive (thank you Greenpeace), so heat pumps aren't worth the $$.

Re:"little known" ???

[JWSmythe]

    Actually, there are lots of people who have no idea that this can be done.

    I live in Florida, and very few people that I've spoken with know anything about it. I haven't been able to find anyone that installs it either, but I'm not looking so hard now that I don't own a house any more.

    There are quite a few interesting variations on this. I won't bother mention the well system, since that's what the article talks about. :)

    One was a dry system, where you simply needed a series of tubes (intentionally said for Sen. Stevens) buried in a horizontal plane at about 10' to 20' deep. You can pump a liquid for a heat exchanger, or even just air, to stabilize the air temperature at about 60F degrees. There are all kinds of options on this. A heat exchanger, or even circulating home air through have both been done successfully. Adding a small amount of outside air can raise or lower the temperature as needed. If 65F is too cold, say 10% outside air could raise that up to 75F.

    Another uses river or lake water. This would depend on your climate to if it would work really well. A friend of mine lives beside a lake that's between 20 to 30 feet deep. Her air conditioner also works very poorly. I introduced the idea of an open loop system, where it would pump water from the lake, through a coil and back to the lake. It would need some degree of large debris filtering, but not a lot (try not to suck up the Loch Ness monster). The coil at the house would simply recirculate just as the regular air handler in the house would, except the coils would maintain about 60 degrees because of the lake. When it's close to 100 degrees outside, and the lake water is in the high 60's at the bottom, a 75 to 80 degree house is a welcome temperature. :)

    Unfortunately, most people look at it as "but, everyone else has a .....". Some people were worried about a reduction in their resale value, because if they sell their home, now there's a "nonstandard" system there. Who would want a house with an almost free heating/cooling system?

    A freon free, low energy system, that takes advantage of the difference in air and ground/water temperature is a wonderful thing.

    This wasn't news, and I wanted to say so too, but people need to be exposed to the idea.