| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent the freezing of water supply at an outlet side of a water heat source evaporator while maintaining high COP operation in a water heater including the water heat source evaporator. <P>SOLUTION: A supercritical tank 26 is interposed in a refrigerant flow passage 100, and branch flow passages 102 in which flow control valves 108, 110 are interposed are provided upstream and downstream of the supercritical tank 26. By making a part of a refrigerant flow in the branch flow passages 102, a refrigerant circulation amount of a heat pump cycle is controlled. Inlet and outlet temperatures of heat source water supplied to plate type heat exchangers 32a, 32b and an inlet temperature of supply water for hot water supply supplied to a gas cooler unit 24 are detected. By using the temperatures as variables, on the condition that a high COP can be obtained and outlet side heat source water temperatures of the plate type heat exchangers 32a, 32b do not reach freezing temperatures, a compressor discharge pressure value P<SB>d</SB>is calculated. The refrigerant circulation amount of the heat pump cycle is controlled to obtain the pressure value Pd. <P>COPYRIGHT: (C)2011,JPO&INPIT |
