Refrigeration system for a transport unit

Abstract

Provided is a refrigeration system for a transport unit. The refrigeration system has a refrigeration cycle comprising a compressor, an evaporator, a condenser fluidically coupled downstream of the compressor and upstream of the evaporator, an expansion valve fluidically coupled downstream of the condenser and upstream of the evaporator, and a suction gas heat exchanger comprising a liquid line side and a suction line side. The liquid line side is fluidically coupled downstream of the condenser and upstream of the expansion valve, and the suction line side is fluidically coupled downstream of the evaporator and upstream of the compressor. The suction gas heat exchanger is configured to transfer heat between refrigerant in the liquid line side and refrigerant in the suction line side.

What is claimed is: 
     
         1 . A refrigeration system for a transport unit, the refrigeration system comprising a refrigeration cycle comprising:
 a compressor;   an evaporator;   a condenser fluidically coupled downstream of the compressor and upstream of the evaporator;   an expansion valve fluidically coupled downstream of the condenser and upstream of the evaporator; and   a suction gas heat exchanger comprising a liquid line side and a suction line side, wherein the liquid line side is fluidically coupled downstream of the condenser and upstream of the expansion valve, and the suction line side is fluidically coupled downstream of the evaporator and upstream of the compressor, whereby the suction gas heat exchanger is configured to transfer heat between refrigerant in the liquid line side and refrigerant in the suction line side.   
     
     
         2 . The refrigeration system of  claim 1 , comprises a non-azeotropic refrigerant in the refrigeration cycle. 
     
     
         3 . The refrigeration system of  claim 1 , wherein the compressor is a multi-stage compressor comprising more than one compression stage. 
     
     
         4 . The refrigeration system of  claim 1 , comprising a gas injector valve fluidically coupled downstream of the condenser and upstream of the first compressor, in a parallel fluid connection with the expansion valve, so as to supply refrigerant expanded through the gas injector valve to the first compressor. 
     
     
         5 . The refrigeration system of  claim 3 , wherein the compressor is a two-stage compressor comprising a compressor low stage and a compressor high stage, and the compressor comprises a gas injector port that opens into the compressor at a location such that a pressure at the gas injector port is between a pressure at an inlet of the compressor low stage and an outlet of the compressor high stage; and
 wherein the gas injector valve is fluidically coupled downstream of the condenser and upstream of the gas injector port.   
     
     
         6 . The refrigeration system of  claim 1 , wherein the refrigeration system is a cascade refrigeration system comprising:
 the refrigeration cycle, wherein the refrigeration cycle is a first refrigeration cycle, the compressor is a first compressor, and the expansion valve is a first expansion valve;   a second refrigeration cycle comprising a second compressor and a second expansion valve; and   a cascade heat exchanger comprising a condenser side fluidically coupled downstream of the first compressor and upstream of the first expansion valve, and an evaporator side fluidically coupled downstream of the second expansion valve and upstream of the second compressor;   wherein the condenser is the condenser side of the cascade heat exchanger.   
     
     
         7 . The refrigeration system of  claim 6  comprising a pre-cooler, the pre-cooler comprising a first side and a second side, the first side being fluidically coupled downstream of the first compressor and upstream of the condenser side of the cascade heat exchanger, whereby the pre-cooler is configured to transfer heat between refrigerant in the first side and refrigerant in the second side. 
     
     
         8 . The refrigeration of  claim 7 , wherein the second side of the pre-cooler is fluidically coupled in the second refrigeration cycle, whereby the pre-cooler is configured to transfer heat between refrigerant in the first refrigeration cycle and refrigerant in the second refrigeration cycle. 
     
     
         9 . The cascade refrigeration system of  claim 6 , comprising an economiser expansion valve fluidically coupled downstream of the second compressor and upstream of the second side of the pre-cooler. 
     
     
         10 . The cascade refrigeration system of  claim 9 , wherein the economiser expansion valve is in a parallel fluidic connection with the second expansion valve. 
     
     
         11 . The cascade refrigeration system of  claim 6 , comprising an economiser heat exchanger, the economiser heat exchanger comprising:
 a first economiser side fluidically coupled downstream of the second compressor and upstream of the second expansion valve; and   a second economiser side fluidically coupled downstream of the second compressor and upstream of the second side of the pre-cooler.   
     
     
         12 . The refrigeration system of  claim 1 , wherein the evaporator comprises a first fluid channel, a second fluid channel, an inlet, and a valve arrangement fluidically coupled between the inlet and the first and second fluid channels,
 wherein the first and second fluid channels are configured to pass refrigerant from the inlet through the evaporator, so that heat can be exchanged between the refrigerant in the first and second fluid channels and an external fluid that is external to the first and second fluid channels, in use, and   wherein the valve arrangement is configurable in a first configuration to fluidically couple both of the first and second fluid channels to the inlet, or in a second configuration to fluidically couple one of the first and second fluid channels to the inlet and to fluidically isolate the other of the first and second fluid channels from the inlet.   
     
     
         13 . A heat exchanger for a refrigeration system, the heat exchanger comprising a first fluid channel, a second fluid channel, an inlet, and a valve arrangement fluidically coupled between the inlet and the first and second fluid channels,
 wherein the first and second fluid channels are configured to pass refrigerant from the inlet through the evaporator, so that heat can be exchanged between the refrigerant in the first and second fluid channels and an external fluid that is external to the first and second fluid channels, in use, and   wherein the valve arrangement is configurable in a first configuration to fluidically couple both of the first and second fluid channels to the inlet, or in a second configuration to fluidically couple one of the first and second fluid channels to the inlet and to fluidically isolate the other of the first and second fluid channels from the inlet.   
     
     
         14 . A transport unit comprising a cargo space for storing cargo and the refrigeration system of  claim 1 , wherein the evaporator is configured to transfer heat between the cargo space and refrigerant in the evaporator. 
     
     
         15 . The transport unit of  claim 14 , comprising a parts storage space for storing replacement parts for the refrigeration system, wherein the parts storage space is located outside the cargo space. 
     
     
         16 . A marine vessel comprising the refrigeration system of  claim 1 , the heat exchanger of  claim 13 , or the transport unit of  claim 14 .