The cooling process involves the extraction of heat energy from the air in the building, and moving it into the earth. Transferring the heat from the air in the building to the earth involves a cycle of expansion, condensation, compression, condensation and evaporation. A refrigerant is used as the heat transfer medium.
The cooling cycle starts as the compressor delivers refrigerant to the water-to-refrigerant heat exchanger. Heat from the refrigerant is absorbed by (rejected into) the low temperature source (earth loop fluid or well water) resulting in the refrigerant turning cold. The cold refrigerant passes through a refrigerant-to-air heat exchanger. As warm, humid air from the return air duct system is passed over the cold air coil, the air is cooled and dehumidified the returned into the building, cooling the space.
The heat from the warm air that returns to the unit is absorbed by the cold refrigerant, turning the refrigerant into a hot gas. The hot refrigerant is returned to the compressor where the process is repeated continuously during the cooling process. A portion of the heat returning to the compressor (from the hot return air) is diverted to another refrigerant circuit that generates hot water and delivers it to the water heater by way of a small pump.