To prevent overheating of a secondary refrigerant of a gas cooler for hot water supply or a gas cooler for heating, in a hot water supply heating system having the gas cooler for hot water supply and the gas cooler for heating in one heat pump circuit.
In this hot water supply heating system, a primary refrigerant is circulated to the gas coolers 7, 8 for hot water supply and the gas cooler 9 for heating by being compressed in multiple stages by a low-stage compressor 5 and a high-stage compressor 6 in the heat pump circuit 2A in a normal operation performing heating and hot water supply. Besides, when only the heating is necessary, a compression ratio of the low-stage compressor 5 and the high-stage compressor 6 is changed to control a temperature of the primary refrigerant flowing to the first gas cooler 7 for hot water supply becomes lower than a boiling point of the secondary refrigerant for hot water supply. When only the hot water supply is necessary, the low-pressure compressor 5 is bypassed by a bypass passage 21 in the heat pump circuit 2. Thus the primary refrigerant compressed in single stage by the high-stage compressor 6, is circulated to the gas coolers 7, 8 for hot water supply and the gas cooler 9 for heating, and the circulation of primary refrigerant and the refrigerant temperature corresponding to the load can be achieved.
YOSHIMI ATSUSHI
YAMADA TAKUO
OKUDA NORIYUKI
