| 摘要 |
PROBLEM TO BE SOLVED: To obtain desired hot water while protecting a heat pump even when a temperature of a heat source fluid is high, and to cool the heat source fluid to a temperature lower than a water supply temperature, in a feedwater heating system applying the heat pump.SOLUTION: A heat pump 4 pumps up heat from a heat source fluid passing through an evaporator 15, and heats water passing through a condenser 13. Feedwater to a water supply tank 3 through a first water supply passage 8 is successively passed through a first heat exchanger 17, a subcooler 16 and the condenser 13. The heat source fluid is successively passed through a first heat exchanger 17 and the evaporator 15. The first heat exchanger 17 is an indirect heat exchanger between the feedwater to the water supply tank 3 through the first water supply passage 8, and the heat source fluid to the evaporator 15. The subcooler 16 is an indirect heat exchanger between the feedwater to the water supply tank 3 through the first water supply passage 8 and a refrigerant from the condenser 13 to an expansion valve 14. |
