Patent ID: 7918106

Claim:
A refrigeration system including a refrigerant circuit that includes a low-pressure stage compressor, a high-pressure stage compressor and a gas-liquid separator for intermediate-pressure refrigerant and operates in a two-stage compression and two-stage expansion refrigeration cycle, wherein the refrigerant circuit further includes a low-pressure stage oil separating device for returning refrigerating machine oil separated out of refrigerant discharged from the low-pressure stage compressor to the suction input of the low-pressure stage compressor and a high-pressure stage oil separating device for returning refrigerating machine oil separated out of refrigerant discharged from the high-pressure stage compressor to the suction input of the high-pressure stage compressor, and the rate of oil separated out of refrigerant by the low-pressure stage oil separating device is set lower than the rate of oil separated out of refrigerant by the high-pressure stage oil separating device.