How it Works: Ground-Source Heat Pumps
Heating and cooling, courtesy of the earth
A ground-source heat pump uses the relatively stable temperature of the earth below 20 ft. to keep a house cool in the summer and warm in the winter. It works by cycling a refrigerant back and forth between the ground and the house. In heating mode, the pump uses the ground as a heat source; in cooling mode, it uses the ground as a heat sink.
Drawings: Don Foley