| 摘要 |
PROBLEM TO BE SOLVED: To improve defrosting capacity in a heating cycle, and to improve defrosting finish determining accuracy. SOLUTION: A refrigerating cycle has a compressor 1, a four-way valve 8, an indoor heat exchanger 3, a pressure reducer 4 and an outdoor heat exchanger 5, and has a first bypass circuit 18 connecting a part between the outdoor heat exchanger 5 and the pressure reducer 4 and a part between the compressor 1 and a delivery pipe 2, and a second bypass circuit 19 connecting the delivery pipe 2 of the compressor 1 to a suction part of the compressor 1, and is constituted by arranging an opening-closing mechanism 7 in the first and second bypass circuits 18 and 19. Heating defrosting operation can melt frost by raising the refrigerant temperature and pressure of the outdoor heat exchanger 5, without sending cold air into a room, by putting the pressure reducer 4 in a blocked-up state, by changing the four-way valve 8 to a cooling operation cycle from the heating cycle, after performing defrosting operation of the heating cycle up to a predetermined condition. The pressure reducer 4 is opened in predetermined opening, and the defrosting finish determining accuracy can be improved by circulating a refrigerant a little to the indoor heat exchanger 3. COPYRIGHT: (C)2009,JPO&INPIT
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