Abstract: A heat pump system is disclosed that utilizes an accumulator fluidly connected between a boost compressor output and a primary compressor input. The accumulator is multifunctional in that it allows the refrigerant from the boost compressor to be cooled with refrigerant from other parts of the system if necessary. The accumulator also serves to receive and cool the oil separated from the refrigerant near the output of the primary compressor. A method for distributing oil among the compressors is also disclosed.

Abstract: A heat pump system including a first heating/cooling exchange loop including a refrigerant to water heat exchanger to produce a first output. A second heating/cooling exchange loop includes a refrigerant to forced air heat exchanger to produce a second output. A compressor is fluidly coupled to the first heating/cooling exchange loop and the second heating/cooling exchange loop. A controller is connected to control the first output and the second output and to transmit control signals to the at least one compressor, for balancing the first output and the second output responsive to a structural heating/cooling load.