In the heating mode, the water circulating in the earth loop is colder than the surrounding ground. This causes the water to absorb energy, in the form of heat, from the earth. The water carries this energy to the heat exchanger in the pump. In the heat exchanger, refrigerant absorbs the heat energy from the water. The water now leaves the heat exchanger at a colder temperature, and circulates through the earth loop to pick up more energy.
The refrigerant gas, which contains energy gained from the earth loop, travels from the heat exchanger to the compressor. In the compressor, the refrigerant temperature rises to 160°. From the compressor, the superheated refrigerant travels to the air heat exchanger. Here, the heat pump’s blower circulates air across the air coil, increasing the temperature of the air, which is blown through ductwork to heat the home. After refrigerant releases its heat energy to the air, it then flows to the earth loop heat exchanger to start the cycle again.