An air to water heat pump chiller can be used in a cascade system with other water-to-water or water-to-air heat pumps to provide a highly efficient and reliable source of cooling. In a cascade system, multiple heat pumps are connected in series, with the output of the air-to-water heat pump serving as the input for the intermediate loop for the water-to-water or water-to-air heat pumps. This allows the heat pumps to operate at a higher overall efficiency, as the cooling capacity of each heat pump is increased through the use of the waste heat generated by the other heat pumps in the system.
By using an air to water heat pump chiller in a cascade system, It reduces the lift on each heat pump and allows the air-to-water heat pump to keep working at lower ambient temperatures since the hot water temperature setpoint is lower. Additionally, buildings with simultaneous heating and cooling loads can transfer the heat within the building rather than having an air-to water heat pump and a chiller both operating at full lift.