Patent ID: 6880352

Claim:
A heat pump apparatus having a refrigerating cycle comprising: a compressor, a gas cooler, a pressure reducing device, and an evaporator in which water can be heated by the gas cooler, wherein said compressor comprises a two-stage compression type rotary compressor having a shell case, an electric motor portion and a compressing portion driven by the electric motor portion, the electric motor portion and the compressing portion being accommodated in said shell case, and the compressor portion having a two-stage structure including a first-stage compressing portion and a second-stage compressing portion which are mounted in the shell case, wherein at least a part of refrigerant compressed to an intermediate pressure in the first-stage compressing portion is passed through said shell case to the second-stage compressing portion and compressed to a high pressure in the second-stage compressing portion, and the high-pressure refrigerant is discharged from the second-stage compressing portion to the outside of said shell case, and wherein said heat pump apparatus further comprises a defrosting circuit for leading the intermediate-pressure refrigerant from the first-stage compressing portion of said compressor to said evaporator with bypassing said gas cooler and said pressure reducing device.