Abstract: The invention relates to a three function heat pump system which provides space heating, space cooling and hot water production. The system permits hot water production all year long without operation of the system in the heating or cooling modes. The system also provides a check valve arrangement which allows passage of a refrigerant through the receiver in all three modes without reversing the flow of the refrigerant through the receiver. The valving arrangement also prevents migration of the refrigerant from the liquid receiver to a thermal storage tank during the hot water production mode. In addition, the valve arrangement allows the refrigerant to pass through throttle or expansion valves when the liquid is passing from the liquid receiver to the thermal storage tank and outdoor air coil, while bypassing the expansion valves when the refrigerant passes from the outdoor air coil and the thermal storage tank to the liquid receiver inlet.

Abstract: The invention relates to a three-function heat pump system which provides space heating, space cooling and hot water. The system permits hot water production all year long without operation of the system in the heating or cooling modes. To this end, the system employs a large storage tank and a relatively smaller hot water tank. A heat exchanger within the hot water tank is sized sufficiently to permit the hot water heat exchanger to function as a system condenser, thereby permitting the refrigerant to bypass the large storage tank. The system is packaged in a compact unit in which the compressor of the system is located within an insulated container with the domestic hot water tank. The crankcase of the compressor therefore remains warm to prevent migration of the refrigerant to the compressor during off seasons. The location of the compressor adjacent to the hot water tank eliminates the need for less energy efficient resistance crankcase heaters.