Refrigerating cycle system using carbon dioxide as refrigerant

Abstract

A refrigerating cycle system of a vapor compression system has a constitution wherein a first compressor, a first radiator, an expansion mechanism, a heat absorber, and a second compressor connected sequentially and circularly. A CO 2 refrigerant is circulated in the sequence of the first compressor→the first radiator→the expansion mechanism→the heat absorber→the second compressor→the first compressor. The rotating drive shaft of the second compressor is connected to the rotating output shaft of the expansion mechanism with a common shaft. Thereby, since the drive force of the second compressor is obtained from the power generated by the refrigerant expanding action of the expansion mechanism, the power of the first compressor consumed for elevating the pressure of the refrigerant to a predetermined pressure can be minimized.

What is claimed is:  
     
         1 . A refrigerating cycle system having a refrigerant pipe for circulating a carbon dioxide refrigerant sequentially to a first compressor, a first radiator, an expansion mechanism, and a heat absorber, and discharging heat from said first radiator in a supercritical state, 
 wherein a second compressor is provided in the refrigerant pipe between said heat absorber and said first compressor, and a rotating drive shaft of said second compressor and a rotating output shaft of said expansion mechanism are connected to each other.    
     
     
         2 . The refrigerating cycle system according to  claim 1 , provided with a bypass pipe one end of which is connected to the refrigerant pipe connected to the gas inlet of said second compressor, and the other end of which is connected to the refrigerant pipe connected to the gas outlet of said second compressor to bypass said second compressor; and 
 said bypass pipe is provided with a switching valve.    
     
     
         3 . The refrigerating cycle system according to  claim 1 , wherein said second compressor and said expansion mechanism are composed of a scroll-type compression/expansion mechanism.  
     
     
         4 . The refrigerating cycle system according to  claim 2 , wherein said second compressor and said expansion mechanism are composed of a scroll-type compression/expansion mechanism.  
     
     
         5 . The refrigerating cycle system according to  claim 1 , wherein said refrigerant pipe between said first compressor and said second compressor is provided with a second radiator.  
     
     
         6 . The refrigerating cycle system according to  claim 2 , wherein said refrigerant pipe between said first compressor and said second compressor is provided with a second radiator.  
     
     
         7 . The refrigerating cycle system according to  claim 3 , wherein said refrigerant pipe between said first compressor and said second compressor is provided with a second radiator.  
     
     
         8 . The refrigerating cycle system according to  claim 4 , wherein said refrigerant pipe between said first compressor and said second compressor is provided with a second radiator.