High Side Pressure Regulation For Transcritical Vapor Compression System

Abstract

An expensive expansion device may be eliminated in favor of a less expensive pressure regulator in a CO 2 vapor compression system such as is used in a bottle cooler or small-capacity air conditioner, refrigerator, or other system.

1 . A refrigeration system ( 60 ;  80 ;  100 ;  120 ;  140 ;  160 ;  180 ) comprising:
 a compressor ( 22 ) for driving a refrigerant along a flow path ( 62 ;  82 ;  102 ;  122 ;  142 ;  162 ;  182 ) in at least a first mode of system operation;   a first heat exchanger ( 24 ) along the flow path downstream of the compressor in the first mode;   a second heat exchanger ( 28 ) along the flow path upstream of the compressor in the first mode; and   a pressure regulator ( 68 ;  72 ;  88 ;  92 ;  108 ,  110 ;  124 ,  126 ;  148 ,  152 ;  164 ;  188 ;  190 ) in the flow path downstream of the first heat exchanger ( 24 ) and upstream of the second heat exchanger ( 28 ) in the first mode.   
   
   
       2 . The system of  claim 1  wherein the pressure regulator comprises a non-valve fixed orifice expansion device ( 68 ;  72 ;  88 ;  92 ;  108 ;  126 ;  148 ;  152 ). 
   
   
       3 . The system of  claim 1  wherein the pressure regulator comprises a non-valve fixed orifice expansion device ( 126 ;  148 ) in series with a solenoid valve ( 124 ;  150 ) with a valve element having an orifice. 
   
   
       4 . The system of  claim 1  wherein the pressure regulator comprises a non-valve fixed orifice expansion device ( 88 ;  148 ) in series with a parallel combination of a solenoid valve ( 90 ;  150 ) and bypass conduit ( 86 ;  146 ). 
   
   
       5 . The system of  claim 1  wherein there are first and second such pressure regulators in parallel. 
   
   
       6 . The system of  claim 1  wherein:
 the refrigerant comprises, in major mass part, CO 2 ; and   the first and second heat exchangers are refrigerant-air heat exchangers.   
   
   
       7 . The system of  claim 1  wherein:
 the first and second heat exchangers and compressor are removable from a housing of the system as a unit without need to previously empty contents of the system.   
   
   
       8 . The system of  claim 1  wherein:
 the refrigerant consists essentially of CO 2 ; and   the first and second heat exchangers are refrigerant-air heat exchangers each having an associated fan, a first mode air flow across the first heat exchanger being an external to external flow and a first mode airflow across the second heat exchanger being a recirculating internal airflow.   
   
   
       9 . The system of  claim 1  being a cooler containing:
 a plurality of beverage containers in a 0.3-4.0 liter size range.   
   
   
       10 . The system of  claim 9  wherein the cooler is selected from the group consisting of:
 a cash-operated vending machine;   a transparent door front, closed back, display case; and   a top access cooler chest.   
   
   
       11 . A refrigeration system comprising:
 a compressor driving a CO 2 -based refrigerant along a flow path in at least a first mode of system operation;   a first heat exchanger along the flow path downstream of the compressor   a second heat exchanger along the flow path upstream of the compressor; and   means in the flow path downstream of the first heat exchanger and upstream of the second heat exchanger for expanding the refrigerant in the absence of an electronic expansion device.