Refrigeration circuit

Abstract

A refrigeration circuit includes one first compressor, a first gas-cooler, connected to the first compressor through a common discharge line, a medium temperature expansion valve, a medium temperature heat exchanger, a liquid receiver that is connected to an outlet liquid line that splits in a first liquid line that connects with the medium temperature heat exchanger and a second liquid line that has a first expansion valve, to a first pressure reduction valve and to a first heat exchanger. The refrigerant flowing through the second liquid line is also mixed with the refrigerant from the first liquid line leaving the medium temperature heat exchanger and the mixture enters the first heat exchanger to exchange heat with the refrigerant in the first liquid line to be directed to the first compressor through a suction line.

1 . A refrigeration circuit, configured to use CO2 as refrigerant, comprising:
 at least one first compressor,   a first gas-cooler, connected to the at least one first compressor through a common discharge line,   a medium temperature expansion valve,   a medium temperature heat exchanger,   a liquid receiver that is connected to:
 an outlet liquid line that splits in a first liquid line that connects with the medium temperature heat exchanger and a second liquid line that comprises a first expansion valve, 
   a first pressure reduction valve located on a gas-cooler outlet line connecting the outlet of the first gas-cooler with an inlet of the liquid receiver, and   a first heat exchanger,   
       wherein, 
       the refrigerant flowing through the second liquid line and depressurized by the first expansion valve is also mixed with the refrigerant from the first liquid line leaving the medium temperature heat exchanger and the mixture enters the first heat exchanger to exchange heat with the refrigerant in the first liquid line to be directed to the at least one first compressor through a suction line. 
     
     
         2 . The refrigeration circuit of  claim 1 , further comprising:
 an outlet vapor line, comprising a second pressure reduction valve, which connects the liquid receiver with the suction line at the outlet of the first heat exchanger, and   a third heat exchanger that exchanges heat between the refrigerant flowing through the gas-cooler outlet line upstream the first pressure reduction valve, and the refrigerant flowing through the suction line after mixing with the outlet vapor line.   
     
     
         3 . The refrigeration circuit of  claim 2 , that further comprises:
 a first motorised multi way valve located in the suction line either at the inlet or at the outlet of the third heat exchanger, and   a first pipe connected to the first motorised multi way valve and bypassing the third heat exchanger   
       so that the refrigerant flows from the first heat exchanger mixed with the refrigerant from the outlet vapor line to the at least one first compressor either through the third heat exchanger, directly through the first pipe, or as a mixture through both elements. 
     
     
         4 . The refrigeration circuit of  claim 1 , that comprises:
 a second compressor connected to the at least one first compressor in parallel to the common discharge line,   a second heat exchanger that exchanges heat between the refrigerant leaving the first gas-cooler and the refrigerant flowing through a first fluid line that branches from the gas-cooler outlet line, either at the inlet or at the outlet of the third heat exchanger, and depressurized by a third expansion valve, and   a second pipe that connects the inlet of the second compressor with the first fluid line leaving the second heat exchanger.   
     
     
         5 . The refrigeration circuit of  claim 4 , that comprises:
 a first vapor line with a first motorised valve, connecting the outlet vapor line to the first fluid line at the inlet of the second heat exchanger.   
     
     
         6 . The refrigeration circuit of  claim 4 , that comprises:
 a cooling line that connects the first liquid line and the first vapor line and further comprises a cooling coil located within the liquid receiver and a fourth expansion valve.   
     
     
         7 . The refrigeration circuit of  claim 1 , wherein the discharge line comprises a second motorised multi way valve that is connected to the inlet of a fourth heat exchanger through a first branch, the outlet of the fourth heat exchanger being connected to the inlet of the first gas-cooler. 
     
     
         8 . The refrigeration circuit of  claim 7 , wherein the discharge line, comprises a third motorised multi way valve that is connected to the outlet gas-cooler line through a second branch, bypassing the first gas-cooler. 
     
     
         9 . The refrigeration circuit of  claim 8 , that further comprises:
 a first check valve located in the gas-cooler outlet line-upstream the connection to the second branch,   a third branch, comprising a third motorised valve that connects the inlet to the first gas-cooler with the outlet vapor line, and   a fourth branch comprising a second expansion valve and a second check valve, that connects the first liquid line with the gas-cooler outlet line upstream the first check valve.   
     
     
         10 . The refrigeration circuit of  claim 4 , further comprising:
 a second fluid line, with a second motorised valve, that connects the gas-cooler outlet line at the outlet of the third heat exchanger with the liquid receiver,   a pressure increaser device located at the outlet of the second compressor,   a fourth fluid line that connects the second pipe to the pressure increaser device,   a pressure exchanger configured to exchange pressure between the refrigerant flowing through the second fluid line and the refrigerant flowing through the fourth fluid line.   
     
     
         11 . The refrigeration circuit of  claim 4 , further comprising:
 a second fluid line, with a second motorised valve, that connects the gas-cooler outlet line at the outlet of the third heat exchanger with the liquid receiver,   a fifth fluid line connecting the second pipe with the first gas-cooler outlet line and comprising a second gas-cooler and a pump, and   a pressure exchanger configured to exchange pressure between the refrigerant flowing through the second fluid line and the fifth fluid line.   
     
     
         12 . The refrigeration circuit of  claim 4 , further comprising:
 a second fluid line, with a second motorised valve, that connects the gas-cooler outlet line at the outlet of the third heat exchanger with the liquid receiver,   a sixth fluid line connecting the second pipe with the first gas-cooler outlet line,   a pressure exchanger configured to exchange pressure between the refrigerant flowing through the second fluid line and the sixth fluid line, and wherein the first gas-cooler comprises an additional circuit where the sixth fluid line is connected downstream the pressure exchanger, and   a pump located in the sixth fluid line at the outlet of the additional circuit.   
     
     
         13 . The refrigeration circuit of  claim 10 , that comprises:
 a third compressor connected to the rest of the compressors in parallel to the common discharge line,   a fourth motorised multi-way valve located on the second pipe-feeding the second compressor and connected to the suction line, wherein the fourth motorised multi-way valve is configured to switch a refrigerant flow between a refrigerant flowing through the suction line to the pressure exchanger and a refrigerant flowing through the second pipe to the pressure exchanger.   
     
     
         14 . The refrigeration circuit of  claim 1 , that further comprises: a low temperature liquid line connecting the first liquid line with the suction line, the low temperature liquid line comprising:
 a low temperature expansion valve,   a low temperature heat exchanger,   a low temperature compressor, and   a desuperheater.   
     
     
         15 . The refrigeration circuit of the  claim 14 , wherein the low temperature liquid line at the outlet of the low temperature heat exchanger is connected to the first heat exchanger-upstream the low temperature compressor, the first heat exchanger being configured to exchange heat between the refrigerant in the low temperature liquid line and the refrigerant flowing through the first liquid line. 
     
     
         16 . The refrigeration circuit of the  claim 15 , that comprises:
 a seventh motorised multi-way valve disposed downstream the low temperature heat exchanger and   a seventh fluid line that connects the seventh motorised multi-way valve with the inlet of the low temperature compressor,   
       so that
 the refrigerant may either flow to the low temperature compressor, bypassing the first heat exchanger, or to the first heat exchanger. 
 
     
     
         17 . The refrigeration circuit of  claim 14 , that further comprises a sixth motorized multi way valve located at the outlet of the desuperheater,
 wherein
 the sixth motorized multi valve is configured so that the refrigerant flowing from the desuperheater can be switched between the suction line to flow to the at least one first compressor and the sixth fluid line at the inlet of the pressure exchanger. 
   
     
     
         18 . The refrigeration circuit of  claim 2 , that comprises:
 a second compressor connected to the at least one first compressor in parallel to the common discharge line,   a second heat exchanger that exchanges heat between the refrigerant leaving the first gas-cooler and the refrigerant flowing through a first fluid line that branches from the gas-cooler outlet line, either at the inlet or at the outlet of the third heat exchanger, and depressurized by a third expansion valve, and   a second pipe that connects the inlet of the second compressor with the first fluid line leaving the second heat exchanger.   
     
     
         19 . The refrigeration circuit of  claim 3 , that comprises:
 a second compressor connected to the at least one first compressor in parallel to the common discharge line,   a second heat exchanger that exchanges heat between the refrigerant leaving the first gas-cooler and the refrigerant flowing through a first fluid line that branches from the gas-cooler outlet line, either at the inlet or at the outlet of the third heat exchanger, and depressurized by a third expansion valve, and   a second pipe that connects the inlet of the second compressor with the first fluid line leaving the second heat exchanger.