Ejector Cycle Heat Recovery Refrigerant Separator

Abstract

A system ( 170; 300; 400 ) comprising a compressor ( 22 ). A heat rejection heat exchanger ( 30; 420 ) is coupled to the compressor to receive refrigerant compressed by the compressor. A separator ( 180 ) has: a vessel ( 181 ); an inlet ( 50 ) coupled to the heat rejection heat exchanger to receive refrigerant; a first outlet ( 54 ) in communication with a headspace of the vessel; and a second outlet ( 52, 52 ′) in communication with a lower portion of the vessel. The system has a heat exchanger ( 182; 220; 220′; 220″; 220 ′″) for transferring heat from refrigerant passing from a heat rejection heat exchanger to liquid refrigerant in the separator.

1 . A system ( 170 ;  300 ;  400 ) comprising:
 a compressor ( 22 );   a heat rejection heat exchanger ( 30 ;  420 ) coupled to the compressor to receive refrigerant compressed by the compressor;   a separator ( 180 ) having:
 a vessel ( 181 ); 
 an inlet ( 50 ) coupled to the heat rejection heat exchanger to receive refrigerant; 
 a first outlet ( 54 ) in communication with a headspace of the vessel; 
 a second outlet ( 52 ,  52 ′) in communication with a lower portion of the vessel; 
   a heat absorption heat exchanger ( 64 ); and   means ( 182 ;  220 ;  220 ′;  220 ″;  220 ″') for transferring heat from refrigerant passing from the heat rejection heat exchanger to liquid refrigerant in the separator.   
     
     
         2 . The system of  claim 1  further comprising:
 an expansion device ( 38 ;  330 ;  430 ) between the heat rejection heat exchanger and the separator inlet. 
 
     
     
         3 . The system of  claim 2  wherein the expansion device is:
 an ejector ( 38 ) having:
 a primary inlet ( 40 ) coupled to the heat rejection heat exchanger to receive refrigerant; 
 a secondary inlet ( 42 ); and 
 an outlet ( 44 ) coupled to the separator inlet. 
 
 
     
     
         4 . The system of  claim 3  wherein the ejector secondary inlet is coupled to receive refrigerant from the separator second outlet by an additional expansion device ( 70 ) and the heat rejection heat exchanger. 
     
     
         5 . The system of  claim 3  wherein the separator first outlet is coupled to a suction port ( 24 ) of the compressor. 
     
     
         6 . The system of  claim 2  wherein the expansion device is:
 an expansion valve ( 330 ;  430 ). 
 
     
     
         7 . The system of  claim 6  further comprising:
 a pump ( 320 ) coupling the separator second outlet to an inlet ( 66 ) of the heat absorption heat exchanger. 
 
     
     
         8 . The system of  claim 7  wherein:
 a flowpath through the pump merges with a flowpath through the expansion valve at a junction ( 312 ) upstream of the inlet ( 66 ) of the heat absorption heat exchanger. 
 
     
     
         9 . The system of  claim 1  wherein the separator first outlet is coupled to the compressor. 
     
     
         10 . The system of  claim 9  wherein the separator first outlet is coupled to a suction port ( 24 ) of the compressor. 
     
     
         11 . The system of  claim 9  wherein the outlet is coupled to an interstage of the compressor. 
     
     
         12 . The system of  claim 9  wherein the compressor is the high pressure stage ( 22 B) of a two-stage system. 
     
     
         13 . The system of  claim 9  wherein the separator is configured to:
 provide mainly liquid refrigerant to an expansion device upstream of the heat absorption heat exchanger; and 
 provide mainly vapor refrigerant to the suction port of the compressor. 
 
     
     
         14 . The system of  claim 1  wherein:
 refrigerant comprises at least 50% carbon dioxide, by weight. 
 
     
     
         15 . A method for operating the system of  claim 1  comprising running the compressor in a first mode wherein:
 the refrigerant is compressed in the compressor; 
 refrigerant received from the compressor by the heat rejection heat exchanger rejects heat in the heat rejection heat exchanger to produce initially cooled refrigerant; 
 the initially cooled refrigerant passes through the expansion device; 
 an outlet flow of refrigerant from the expansion device passes to the separator to separate said liquid refrigerant from refrigerant vapor; 
 said heat is transferred from said refrigerant passing from the heat rejection heat exchanger to said liquid refrigerant. 
 
     
     
         16 . A refrigerant separator comprising:
 a vessel ( 181 );   an inlet ( 50 );   a first outlet ( 54 ) in communication with a headspace of the vessel;   a second outlet ( 52 ; 52 ′) in communication with a lower portion of the vessel; and   a heat exchanger ( 182 ) having:
 an inlet ( 186 ); 
 an outlet ( 188 ); and 
 a portion through the lower portion of the vessel. 
   
     
     
         17 . The system of  claim 16  wherein the heat exchanger comprises:
 an upstream spiral leg and a downstream straight leg. 
 
     
     
         18 . A system comprising the refrigerant separator of  claim 16  and further comprising:
 a compressor ( 22 ); 
 a heat rejection heat exchanger ( 30 ;  420 ) coupled to the compressor to receive refrigerant compressed by the compressor; and 
 an ejector ( 38 ) having:
 a primary inlet ( 40 ) coupled to the heat rejection heat exchanger to receive refrigerant; 
 a secondary inlet ( 42 ); and 
 an outlet ( 44 ) coupled to the separator inlet. 
 
 
     
     
         19 . The system of  claim 1 , wherein the means comprises a heat exchanger ( 182 ) having:
 an inlet ( 186 );   an outlet ( 188 ); and   a portion through the lower portion of the vessel.   
     
     
         20 . The system of  claim 19  the heat exchanger comprises:
 an upstream spiral leg and a downstream straight leg.