Evaporation circuit for alternative refrigerant in a refrigeration system

Abstract

An evaporator circuit for a second refrigerant used in conjunction with a refrigeration circuit of the type operating a refrigeration cycle. The evaporator circuit has a heat exchange stage having a heat exchanger in a refrigerant accumulator in which the second refrigerant is in heat-exchange relation with the first refrigerant circulating in the heat exchanger in the evaporation stage of the refrigeration circuit. The heat exchanger is positioned in the refrigerant accumulator so as to be immersed in the second refrigerant such that the second refrigerant releases heat to the first refrigerant circulating in the heat exchanger. An evaporator stage has an evaporator in which the second refrigerant absorbs heat from a fluid passing through the evaporator, so as to cool the fluid, whereby the second refrigerant circulates between the heat exchange stage and the evaporator stage.

1 . An evaporator circuit for a second refrigerant used in conjunction with a refrigeration circuit of the type operating a refrigeration cycle having a compression stage, a condensation stage, an expansion stage, and an evaporation stage with a first refrigerant, comprising: 
 a heat exchange stage having at least one heat exchanger in a refrigerant accumulator in which the second refrigerant is in heat-exchange relation with the first refrigerant circulating in the heat exchanger in the evaporation stage of the refrigeration circuit, the heat exchanger being positioned in the refrigerant accumulator so as to be immersed in the second refrigerant such that the second-refrigerant releases heat to the first refrigerant circulating in the heat exchanger; and    an evaporator stage having at least one evaporator in which the second refrigerant absorbs heat from a fluid passing through the evaporator, so as to cool the fluid;    whereby the second refrigerant circulates between the heat exchange stage and the evaporator stage.    
   
   
       2 . The evaporation circuit according to  claim 1 , wherein the heat exchange stage has two of the heat exchanger each in a respective refrigerant accumulator, such that the second refrigerant in the refrigerant accumulators is sequentially (1) in heat-exchange relation with the first refrigerant while receiving the second refrigerant from the evaporator stage, and then (2) fed to the evaporator stage, with the first and the second refrigerant accumulators alternating sequentially with respect to one another.  
   
   
       3 . The evaporation circuit according to  claim 1 , further comprising an energy accumulator in fluid communication with the heat exchange stage, such that the second refrigerant having released heat to the first refrigerant may be stored in the energy accumulator, for subsequently being used in the evaporator stage.  
   
   
       4 . The evaporator circuit according to  claim 1 , wherein at least one pump is used to induce fluid circulation between the heat exchange stage and the evaporator stage.  
   
   
       5 . The evaporator circuit according to  claim 1 , wherein a pressure source pressurizes the refrigerant accumulator to induce fluid circulation between the heat exchange stage and the evaporator stage.  
   
   
       6 . The evaporator circuit according to  claim 1 , wherein the second refrigerant changes phase from liquid to solid in the heat-exchange relation with the first refrigerant, a tool being provided on the heat exchanger so as to remove solid build-up of the second refrigerant on the heat exchanger.  
   
   
       7 . A refrigeration system of the type having a refrigeration circuit having a compression stage, a condensation stage, an expansion stage and an evaporation stage through which a first refrigerant circulates, further comprising an evaporator circuit through which circulates a second refrigerant between a heat exchange stage having at least one heat exchanger in a refrigerant accumulator in which the second refrigerant is in heat-exchange relation with the first refrigerant circulating in the heat exchanger in the evaporation stage of the refrigeration circuit, the heat exchanger being positioned in the refrigerant accumulator so as to be immersed in the second refrigerant such that the second refrigerant releases heat to the first refrigerant circulating in the heat exchanger, and an evaporator stage having at least one evaporator in which the second refrigerant absorbs heat from a fluid passing through the evaporator, so as to cool the fluid for refrigeration, whereby the second refrigerant circulates between the heat exchange stage and the evaporator stage.  
   
   
       8 . The refrigeration system according to  claim 7 , further comprising a defrost circuit in which the second refrigerant circulates, and being in a heat exchange relation with the first refrigerant at the condensation stage of the refrigeration circuit so as to absorb heat from the first refrigerant, the defrost circuit being in a controlled fluid communication with the evaporator of the evaporator stage of the evaporation circuit, so as to defrost the at least one evaporator with the second refrigerant that has absorbed heat in the heat exchange relation with the first refrigerant.  
   
   
       9 . The refrigeration system according to  claim 7 , wherein the heat exchange stage has two of the heat exchanger each in a respective refrigerant accumulator, such that the second refrigerant in the refrigerant accumulators is sequentially (1) in heat-exchange relation with the first refrigerant while receiving the second refrigerant from the evaporator stage, and then (2) fed to the evaporator stage, with the first and the second refrigerant accumulators alternating sequentially with respect to one another.  
   
   
       10 . The refrigeration system according to  claim 7 , further comprising an energy accumulator in fluid communication with the heat exchange stage, such that the second refrigerant having released heat to the first refrigerant may be stored in the energy accumulator, for subsequently being used in the evaporator stage.  
   
   
       11 . The refrigeration system according to  claim 7 , wherein at least one pump is used to induce fluid circulation between the heat exchange stage and the evaporator stage.  
   
   
       12 . The refrigeration system according to  claim 7 , wherein the second refrigerant changes phase from liquid to solid in the heat-exchange relation with the first refrigerant, a tool being provided on the heat exchanger so as to remove solid build-up of the second refrigerant on the heat exchanger.  
   
   
       13 . The refrigeration system according to  claim 8 , wherein a pressure source is connected to the at least one evaporator of the evaporator stage to flush the first refrigerant out from the at least one evaporator for subsequent defrost of the evaporator, and after the defrost of the evaporator.  
   
   
       14 . The refrigeration system according to  claim 13 , wherein the pressure source is connected to the refrigerant accumulator so as to pressurize the refrigerant accumulator to induce fluid circulation between the heat exchange stage and the evaporator stage.  
   
   
       15 . A refrigeration system of the type having a refrigeration circuit having a compression stage, a condensation stage, an expansion stage and an evaporation stage through which a first refrigerant circulates, comprising: 
 at least one compressor at the compression stage, the compressor being a magnetic-bearing compressor; and    pressure increasing means upstream of the expansion stage, so as to increase the pressure of the first refrigerant for subsequently being fed to the expansion stage.