I was just at a conference where one of the presentations was about green buildings. And the presenter was speaking about geothermal heat pump technology and how it saves energy and thereby money. I did a little looking around and the information I got made it seem that you still need to heat or cool the water in the system before storing it in the ground. Is this just insulation for the water heat or does the ground actually heat the water? Then how is it that this would work in a harsh winter? I will be looking for more information but was wondering if anyone here knew a good book, web-site, or just knew what was going on.
How it works.
A few feet beneath the surface, the earth's temperature remains fairly constant-ranging from 45º or so in northern latitudes to about 70ºF in the deep south-year round. Geoexchange takes advantage of this constant temperature to provide extremely efficient heating and cooling.
In winter, a water solution circulating through pipes buried in the ground absorbs heat from the earth and carries it into the home. The Geoexchange system inside the home uses a heat pump to concentrate the earth's thermal energy and then to transfer it to air circulated through standard ductwork to fill the interior space with warmth.
Simply put, a GHP works much like the refrigerator in your kitchen, with the addition of a few extra valves that allow heat-exchange fluid to follow two different paths: one for heating and one for cooling. The GHP takes heat from a warm area and exchanges the heat to a cooler area, and vice versa. The beauty of such a system is that it can be used for both heating and cooling—doing away with the need for separate furnace and air-conditioning systems—and for free hot water heating during the summer months. For a more detailed explanation of how GHP systems work, see the sidebar.
The sidebar. (http://www.eere.energy.gov/erec/factsheets/geo_heatpumps.html#sidebar)
The ground heat exchanger in a GHP system is made up of a closed or open loop pipe system. Most common is the closed loop, in which high density polyethylene pipe is buried horizontally at 4-6 feet deep or vertically at 100 to 400 feet deep. These pipes are filled with an environmentally friendly antifreeze/water solution that acts as a heat exchanger. In the winter, the fluid in the pipes extracts heat from the earth and carries it into the building. In the summer, the system reverses and takes heat from the building and deposits it to the cooler ground.
The air delivery ductwork distributes the heated or cooled air through the house's duct work, just like conventional systems. The box that contains the indoor coil and fan is sometimes called the air handler because it moves house air through the heat pump for heating or cooling. The air handler contains a large blower and a filter just like conventional air conditioners.
Thank you very much Iris!!:)