| 摘要 |
PROBLEM TO BE SOLVED: To heat feedwater to a heat pump as intended in a cycle external heat exchanger so as to improve efficiency of the heat pump, in a feedwater heating system applying the heat pump.SOLUTION: Feedwater to a water supply tank 3 through a water supply passage 8, is successively passed through a cycle external heat exchanger 17, a subcooler 16 and a condenser 13. The cycle external heat exchanger 17 is an indirect heat exchanger between the feedwater to the water supply tank 3 through the water supply passage 8 and a heat source fluid. The subcooler 16 is an indirect heat exchanger between the feedwater to the water supply tank 3 through the water supply passage 8 and a refrigerant from the condenser 13 to an expansion valve 14. The heat source fluid is allowed to pass through an evaporator 15 and the cycle external heat exchanger 17 in parallel. |
