TWO-STAGE COMPRESSION DEVICE AND REFRIGERATION/AIR-CONDITIONING APPARATUS EMPLOYING THE SAME

PROBLEM TO BE SOLVED: To provide a two-stage compression device of which the configuration is simplified and the cost is reduced and which is made small-sized and compact by reducing the number of components by omitting an oil separator from the two-stage compression device in which two compressors are connected in series, and a refrigeration/air-conditioning apparatus employing the same.SOLUTION: In a two-stage compression device 2, a refrigerant is compressed on two stages by two compressors 10, 20 at lower-stage and higher-stage sides connected in series. Between the two compressors, the compressor 10 at the lower-stage side is a low-pressure housing type compressor 10, and the compressor 20 at the higher-stage side is a high-pressure housing type compressor 20. An oil reservoir 25 of the high-pressure housing type compressor 20 and an oil reservoir 15 of the low-pressure housing type compressor 10 are connected via oil return piping 27.