Patent attributes
A heat pump system includes: a heat-source-side refrigerant circuit having a heat-source-side compressor, a first usage-side heat exchanger operable as a radiator of heat-source-side refrigerant, and a heat-source-side heat exchanger operable as an evaporator of heat-source-side refrigerant; and a usage-side refrigerant circuit having a usage-side compressor arranged to compress usage-side refrigerant with a pressure of the usage-side refrigerant corresponding to a saturated gas temperature of 65° C. that is 2.8 MPa or less at gauge pressure, a refrigerant-water heat exchanger operable as a radiator of usage-side refrigerant to heat an aqueous medium, and a first usage-side heat exchanger operable as an evaporator of usage-side refrigerant by the radiation of heat-source-side refrigerant. The weight of usage-side refrigerant enclosed in the usage-side refrigerant circuit is one to three times the weight of refrigeration machine oil enclosed to lubricate the usage-side compressor.