Internal liquid suction heat exchanger

Abstract

In one aspect, an evaporator assembly for a refrigeration system is provided. The evaporator assembly includes a pressure vessel having an inlet and an outlet. The outlet is configured to supply refrigerant to a compressor of the refrigeration system. A liquid suction heat exchanger is disposed within the pressure vessel. The liquid suction heat exchanger is configured to receive a liquid refrigerant for heat exchange with the refrigerant in the pressure vessel.

1 . An evaporator assembly for a refrigeration system, the evaporator assembly comprising:
 a pressure vessel having an inlet and an outlet, the outlet configured to supply refrigerant to a compressor of the refrigeration system; and   a liquid suction heat exchanger disposed within the pressure vessel, the liquid suction heat exchanger configured to receive a liquid refrigerant for heat exchange with the refrigerant in the pressure vessel.   
     
     
         2 . The evaporator assembly of  claim 1 , wherein the liquid suction heat exchanger comprises at least one finned tube. 
     
     
         3 . The evaporator assembly of  claim 1 , further comprising a tube bundle configured to receive a fluid for heat exchange with the refrigerant in the pressure vessel. 
     
     
         4 . The evaporator assembly of  claim 3 , wherein the liquid suction heat exchanger is disposed between the tube bundle and the pressure vessel outlet such that refrigerant vaporized against the tube bundle passes the liquid suction heat exchanger for heat exchange therewith. 
     
     
         5 . The evaporator assembly of  claim 1 , further comprising a superheat sensor disposed in the pressure vessel outlet. 
     
     
         6 . The evaporator assembly of  claim 1 , wherein the evaporator assembly is a flooded-type evaporator assembly or a falling film type evaporator assembly. 
     
     
         7 . A refrigeration system comprising:
 a compressor;   a condenser fluidly coupled to the compressor;   an evaporator having an inlet and an outlet, the evaporator fluidly coupled between the condenser and the compressor; and   a liquid suction heat exchanger fluidly coupled between the condenser and the evaporator, the liquid suction heat exchanger disposed within the evaporator for heat exchange between liquid refrigerant from the condenser and refrigerant vapor in the evaporator.   
     
     
         8 . The refrigeration system of  claim 7 , further comprising an oil separator disposed between the compressor and the condenser. 
     
     
         9 . The refrigeration system of  claim 7 , wherein the liquid suction heat exchanger comprises at least one finned tube. 
     
     
         10 . The refrigeration system of  claim 7 , further comprising a tube bundle disposed within the evaporator, the tube bundle configured to receive a fluid for heat exchange with the refrigerant in the evaporator. 
     
     
         11 . The refrigeration system of  claim 10 , wherein the liquid suction heat exchanger is disposed between the tube bundle and the evaporator outlet. 
     
     
         12 . The refrigeration system of  claim 7 , further comprising a superheat sensor disposed in the evaporator outlet. 
     
     
         13 . The refrigeration system of  claim 12 , further comprising an expansion valve disposed between the liquid suction heat exchanger and the evaporator, wherein the expansion valve is operably coupled to the superheat sensor. 
     
     
         14 . The refrigeration system of  claim 7 , wherein the evaporator is a flooded-type evaporator or a falling film type evaporator. 
     
     
         15 . A method of increasing suction superheat in a refrigeration system having a compressor, a condenser, an evaporator, and a liquid suction heat exchanger disposed in the evaporator, the method comprising:
 supplying liquid refrigerant from the condenser to the liquid suction heat exchanger;   cooling the liquid refrigerant in the liquid suction heat exchanger against refrigerant vapor in the evaporator;   supplying the cooled liquid refrigerant to the evaporator;   vaporizing and superheating the cooled liquid refrigerant into the refrigerant vapor;   increasing the superheat of the refrigerant vapor through heat exchange with the liquid refrigerant in the liquid suction heat exchanger; and   supplying the refrigerant vapor to the compressor.   
     
     
         16 . The method of  claim 15 , further comprising measuring the superheat temperature differential relative to the saturation temperature of the refrigerant vapor passing through an outlet of the evaporator. 
     
     
         17 . The method of  claim 16 , further comprising controlling an expansion valve based on the measured superheat, the expansion valve disposed between the liquid suction heat exchanger and the evaporator.