AIR CONDITIONER

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).