Patent ID: 7918096

Claim:
A refrigeration system comprising: a vapor-compression refrigeration cycle refrigerant circuit ( 11 ) including a compressor ( 20 ) and an expander ( 30 ); the compressor ( 20 ) including: a compressor casing ( 24 ); a compression mechanism ( 21 ) disposed within the compressor casing ( 24 ), the compression mechanism ( 21 ) compressing refrigerant drawn in directly from outside the compressor casing ( 24 ) and delivering it into the compressor casing ( 24 ); and an oil sump ( 27 ), formed within the compressor casing ( 24 ), for lubricant oil which is supplied to the compression mechanism ( 21 ); the expander ( 30 ) including: an expander casing ( 34 ); an expansion mechanism ( 31 ) disposed within the expander casing ( 34 ), the expansion mechanism ( 31 ) expanding refrigerant admitted directly from outside the expander casing ( 34 ) and discharging it directly to outside the expander casing ( 34 ); and an oil sump ( 37 ), formed within the expander casing ( 34 ), for lubricant oil which is supplied to the expansion mechanism ( 31 ); wherein there is provided an oil distribution pipe ( 41 ), connected between the oil sump ( 27 ) within the compressor casing ( 24 ) and the oil sump ( 37 ) within the expander casing ( 34 ), for the transfer of lubricant oil; and wherein the expander casing ( 34 ) is connected in the middle of piping on the delivery side of the compressor ( 20 ) so that refrigerant delivered out from the compressor ( 20 ) is distributed through the inside of the expander casing ( 34 ).