Remember, a geothermal heat pump doesn’t create heat by burning fuel, like a furnace does. Instead, in winter it collects the Earth’s natural heat through a series of pipes, called a loop, installed below the surface of the ground or submersed in a pond or lake. Fluid circulates through the loop and carries the heat to the house. There, an electrically driven compressor and a heat exchanger concentrate the Earth’s energy and release it inside the home at a higher temperature. Ductwork distributes the heat to different rooms.
In summer, the process is reversed.

The underground loop draws excess heat from the house and allows it to be absorbed by the Earth. The system cools your home in the same way that a refrigerator keeps your food cool – by drawing heat from the interior, not by blowing in cold air.

The geothermal loop that is buried underground is typically made of high-density polyethylene, a tough plastic that is extraordinarily durable but which allows heat to pass through efficiently. When installers connect sections of pipe, they heat fuse the joints, making the connections stronger than the pipe itself. The fluid in the loop is water or an environmentally safe antifreeze solution that circulates through the pipes in a closed system.

Another type of geothermal system uses a loop of copper piping placed underground. When refrigerant is pumped through the loop, heat is transferred directly through the copper to the earth.

As with any heat pump, geothermal and water-source heat pumps are able to heat, cool, and, if so equipped, supply the house with hot water. Some models of geothermal systems are available with two-speed compressors and variable fans for more comfort and energy savings. Relative to air-source heat pumps, they are quieter, last longer, need little maintenance, and do not depend on the temperature of the outside air.

Egg Geothermal Heating and Cooling uses the Earth’s constant temperature to achieve EER’s (Energy Efficiency Ratings) in the 30′s. The heating COP (Coefficient of Performance) is approaching 5. A 5 COP indicates that the Egg Geothermal Systems are producing 5 units of energy for every unit of electricity consumed. The other 4 come from the Earth. That’s why this technology is called “renewable”.

Chicago’s Green Alley Initiative (photo: Chicago DOT)
Urban alleyways. Grubby places that only scrappy cats or cop-show perps could love, right? Not in Chicago, where the Department of Transportation is giving them some serious TLC with its recently i…