VAPOR INJECTION HEAT PUMP AND CONTROL METHOD

A vapor injection heat pump includes a compressor, a first valve directing a refrigerant of the compressor to a first or second heat exchanger dependent upon a mode of operation, an expansion device receiving the refrigerant from at least one of the heat exchangers, a vapor generator receiving an expanded liquid/vapor refrigerant mix from the first expansion device and directing a vapor component to a first input port of the compressor and a liquid component to at least one of the second heat exchanger and a third heat exchanger, via controlling a second valve, a second expansion device, a third expansion device, and a third valve. A second input of the compressor receives an output refrigerant from at least one of the second heat exchanger and the third heat exchanger dependent upon the mode of operation.