| 摘要 |
PROBLEM TO BE SOLVED: To realize a cooling/heating (hot water supply) system by using supercritical refrigerant without using a four-way switch valve, and to realize reduction of liquid back in starting by liquefied refrigerant (flooded refrigerant) condensed and accumulated in a heat source-side heat exchanger in stopping the operation. SOLUTION: When a heating or hot water supplying operation is started, a switch valve 7 between the heat source-side heat exchanger 11 and a high-pressure gas pipe 3 is opened, a switch valve 8 between the heat source-side heat exchanger 11 and a low-pressure gas pipe 6 is closed, a switch valve 9 between a use-side heat exchanger 12 and the high-pressure gas pipe 3 is closed, a switch valve 10 between the use-side heat exchanger 12 and the low-pressure gas pipe 6 is opened, and expansion valves 15, 16 respectively between each of heat exchangers 11, 12 and a liquid pipe 17 are opened. An inverse cycle is started for a short time, a pressure of the refrigerant is raised to a supercritical state by using a high-pressure sensor 21, and then the operation is switched to a normal operation. COPYRIGHT: (C)2006,JPO&NCIPI
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