Patent ID: 8109116

Claim:
A refrigeration air conditioner comprising: a main compression mechanism for compressing a refrigerant; a gas cooler for cooling the refrigerant compressed; an expansion mechanism for expanding the refrigerant flowing from said gas cooler to recover power; a sub-compression mechanism disposed on a discharge side or a suction side of said main compression mechanism for compressing the refrigerant using the power recovered by said expansion mechanism; an evaporator for evaporating the refrigerant expanded at said expansion mechanism; a first hermetic vessel containing said main compression mechanism and lubricant oil; a second hermetic vessel containing said expansion mechanism, said sub-compression mechanism, and lubricant oil; a first equalizer pipe connecting a bottom portion of said first hermetic vessel, at a position lower than a minimum oil level of said first hermetic vessel, to a bottom portion of said second hermetic vessel, at a position lower than a minimum oil level of said second hermetic vessel; a second equalizer pipe connecting a side of said second hermetic vessel, at a position higher than the minimum oil level of said second hermetic vessel, to a suction side of said main compression mechanism, wherein a space within said second hermetic vessel is isolated from said expansion mechanism and said sub-compression mechanism, and pressure within said second hermetic vessel is independent of pressure within said expansion mechanism and pressure within said sub-compression mechanism.