Patent ID: 7559206

Claim:
A supercritical heat pump cycle system comprising: a compressor for compressing refrigerant; a refrigerant radiator having an inner pressure higher than a critical pressure of the refrigerant, in which the refrigerant discharged from the compressor is heat-exchanged with a fluid passing the refrigerant radiator to heat the fluid in a heating operation; a decompression unit which decompresses the refrigerant flowing from the refrigerant radiator; a refrigerant evaporator for evaporating the refrigerant from the decompression unit; target temperature setting means for setting a target temperature of the fluid; target pressure determining means for determining a heating target control pressure in the refrigerant radiator based on the target temperature of the fluid, during the heating operation, and low-pressure determining means for determining a pressure of a low-pressure refrigerant after being decompressed in the decompression unit, wherein the decompression unit is controlled so that a refrigerant pressure in the refrigerant radiator becomes the target control pressure; and the pressure determining means determines the heating target control pressure in the refrigerant radiator based on the pressure of the low-pressure refrigerant and the target temperature of the fluid, during the heating operation.