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Malcolm Gladwell’s Father explains Geothermal heat pumps

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Malcolm Gladwell, journalist and author of the Tipping Point and Blink, has an interesting post on his blog where his father explains how his newly installed geothermal heat pump system works.

Most of us prefer the temperature in the house in the winter to be nearer 70˚F then 60˚F, so we need to raise the temperature of the relatively warm air a little. For this we use the gas equation that you may remember from High School Physics: PV=RT. Here P is pressure, V is volume, T is absolute temperature, and R is a constant. If we keep the volume constant, we see that the Pressure is proportional to the Temperature. This means that if we want to raise the temperature of the air a little, then we should increase its pressure a little. To see how much, we must work in absolute temperature, which is 273˚+temperature in Celsius (centigrade) . Take an example: suppose the temperature of the water coming out of the ground were 50˚F; that is 10˚C or 273˚+10˚=283˚ absolute. We want to heat the air from 50˚F to say 68˚F. 68˚F is 20˚C or 273˚+20˚=293˚ absolute. Raising the temperature from 283˚ to 293˚, means that we raise it by (293-283)*100/283 percent, or 3.5 %. That small increase in pressure can easily be done by using a compressor.

He then goes into the capital costs for his local market (Canada). For a domestic market with a wide summer/winter temperature differential and plenty of land, it’s a perfect solution.

Technorati Tags: sustainability

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