| 摘要 |
An air conditioner ( 1 ) including a heat source side heat exchanger ( 23 ) constructed such that, when it functions as the evaporator for a refrigerant, the refrigerant flows in from the lower side and flows out from the upper side and having a refrigerant circuit ( 12 ) capable of switching to cause the heat source side heat exchanger ( 23 ) and use side heat exchangers ( 32, 42, 52 ) to function individually as the evaporator or the condenser for the refrigerant. The range of control when evaporation ability of the heat source side heat exchanger ( 23 ) is controlled by a heat source side expansion valve ( 24 ) is expanded. When the heat source side heat exchanger ( 23 ) is operated to function as the evaporator, the air conditioner ( 1 ) causes the refrigerant discharged from a compression mechanism ( 21 ) through a first bypass circuit ( 102 ) to bypass to the suction side of the compression mechanism ( 21 ), switches the heat source side heat exchanger ( 23 ) to operation in which it functions as the condenser, and closes the heat source side expansion valve ( 24 ). By this, a freezing machine oil collected in the heat source side heat exchanger ( 23 ) through a first oil return circuit ( 101 ) is returned to the suction side of the compression mechanism ( 21 ) from the lower part of the heat source side heat exchanger ( 23 ).
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