| 摘要 |
PURPOSE:To reduce the difference of the amount of refrigerant after the outlet of an expansion device remarkably and improve the efficiency of the system by a method wherein a refrigerant cooling unit is provided in a high-pressure high-temperature liquid refrigerant circuit from a hot-water heat exchanger to the expansion device to control the temperature of the liquid refrigerant at the inlet of the expansion device. CONSTITUTION:The high-pressure high-temperature refrigerant circuit 15, from the hot-water supplying heat exchanger 2 to the expansion device 3, is provided with the refrigerant cooling section 14, consisting of first cooling unit 17 equipped with radiating fins 16 and second cooling unit 19 connected thermally to a low-temperature low-pressure refrigerant circuit 18 including a heat collector 4. When water temperature in a hot-water reserving tank 7 is increased by the feed water heating operation of heat pump cycle, a compressing pressure is increased and the outlet temperature of the heat exchanger 2 is increased to a temperature higher than the temperatures of atmosphere and the low-temperature low-pressure refrigerant circuit 18. According to the temperature increase, heat radiations of the radiating fins 16 and the second cooling unit 19 are generated and the inlet temperature of the expansion device becomes a value not different so much from the temperature when water temperature is low. Accordingly, the total amount of refrigerant in the circuit 18 from the expansion device 3 to an accumulator 5 becomes constant substantially, the fluctuation of optimum amount of refrigerant is reduced, over-filling effect of refrigerant is decreased and the efficiency of the system may be improved. |
