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Comment by mxuribe | Hacker News Reader

I had heard that these types of systems existed/were used in places like Iceland (or was it Sweden?)...But I wasn't aware they could be leveraged in areas where there might not be as much underground geothermal activity. Unless, I'm misunderstanding what dependencies are needed for these types of systems to work. In any case, if this is not new, any competition to the way we heat/cool our homes - assuming it brings lower prices/more options - is welcomed!

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They don't depend on geothermal activity. They depend on the relatively constant temp of the ground below the freeze line. In most places if you go down a few feet the earth is 40-50 degrees F. Its basically a heat pump that uses water instead of air.

My sister outside of Pittsburgh, PA has had a https://www.waterfurnace.com for 17 years. Her system has paid for itself a few times over. She has 1500 ft of plastic tubing burried in her front yard.

They don't rely on any special geological phenomena. They work like a regular air conditioner or heat pump (compressor, refrigerant, condenser, evaporator) but instead of pumping heat to/from the outside air, they pump it to/from the ground.

The advantage is that, while the outside air is almost always the wrong temperature (hot in the summer when your pump needs it to absorb heat, cold in the winter when you need to pull heat out of it), the ground is basically always the right temperature.

The disadvantage is install costs because you have to put piping underground by either trenching or drilling.

Geo-thermal is a little misleading because the systems you are talking about use very high temperatures found in volcanic parts of the world, which is obviously pretty easy. A ground source heat pump only requires 10 degrees or more of heat difference, easily found 30 metres below ground in most moderate temperature countries - it then uses the same technology as air-conditioning. Loads of them are already installed in the UK.

Iceland gets a pretty nice chunk of their power from geothermal, and the cost effectiveness of geothermal power on a volcanic island (combined with a cold air temp that makes cooling easy) makes it a remarkably cheap place to mine bitcoin, as the case happens.

Another fun thing made possible by geothermal: Some roads and sidewalks in Reykjavik are actually heated to prevent icing over.

(And before someone says it: Yes, Greenland is colder, but Iceland still gets pretty freaking cold. After walking two miles or so in an Icelandic blizzard once, I feel like I can claim some expertise on the subject.)

There is at least one old house right here in Atlanta, GA that uses geo-thermal.

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