| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an air conditioner which suppresses generation of liquid back and excessive increase of the suction temperature in a normal cycle defrost operation, readily secures heat quantity supplied from a compressor to a refrigerant circuit, and has high reliability.SOLUTION: An air conditioner 100 includes a refrigerant circuit 80 enabling a heating operation in which refrigerant is circulated in the order of a compressor 31, an indoor heat exchanger 21, an expansion valve 35, and an outdoor heat exchanger 33; a discharge-suction bypass circuit 50 having an overheat valve 52 and connected to the refrigerant circuit so that, when the overheat valve is opened, the refrigerant is bypassed from a discharge side to a suction side of the compressor; and a control unit 40. The air conditioner circulates the refrigerant in the refrigerant circuit in the same manner as that in the heating operation, while performing a normal cycle defrost operation in which the refrigerant is bypassed from the discharge side to the suction side of the compressor in the discharge-suction bypass circuit. The control unit controls the opening of the overheat valve to set a ratio between the flow rate of the refrigerant passing through the overheat valve and the flow rate of the refrigerant passing through the expansion valve to a prescribed flow rate ratio in a normal cycle defrost operation.</p> |
