| 摘要 |
PROBLEM TO BE SOLVED: To provide an air conditioner using carbon dioxide as a refrigerant, whereby sufficient heating ability can be obtained regardless of operating conditions. SOLUTION: A compressor, an outdoor heat exchanger, an expansion machine, and an indoor heat exchanger are provided in the refrigerant circuit of this air conditioner. In this refrigerant circuit, a refrigerating cycle is applied by circulating carbon dioxide filled as a refrigerant. When operating this air conditioner for heating, under an operating condition in which a refrigerant evaporating temperature in the outdoor heat exchanger becomes about 0°C, an action by which the high pressure of the refrigerating cycle reaches not less than the critical pressure of the carbon dioxide is performed. On the other hand, under an operating condition in which the refrigerant evaporating temperature reaches low temperatures such as -10°C and -20°C for example, an action by which the high pressure of the refrigerating cycle becomes lower than the critical pressure of the carbon dioxide is performed. COPYRIGHT: (C)2006,JPO&NCIPI |
