REFRIGERATION DEVICE

摘要

An air-conditioning apparatus (1) comprises a four-stage compressor (2), switching mechanisms (31 to 33), intercoolers (51 to 53), oil separators (41 to 43), and a control unit. The four-stage compressor (2) has four compression mechanisms (21 to 24) connected in series. The switching mechanisms (31 to 33) are connected to blow-out pipes (101b to 103b) of the compression mechanisms (21 to 23). The switching mechanisms (31 to 33) switch between a cooling operation cycle and a heating operation cycle. The intercoolers (51 to 53) cool a refrigerant blown out from the compression mechanisms (21 to 23) during the cooling operation cycle. The oil separators (41 to 43) are placed between the switching mechanisms (31 to 33) and the intercoolers (51 to 53). The oil separators (41 to 43) separate a lubricating oil from the refrigerant blown out from the compression mechanisms (21 to 23) during the cooling operation cycle. A control unit controls the four-stage compressor (2) and the switching mechanisms (31 to 33).