Enhanced economizer operation in a chiller

Abstract

A refrigeration system includes a compressor, a heat rejecting heat exchanger, an expansion device, and a heat absorbing heat exchanger fluidly connected to form a closed loop through which a refrigerant is configured to circulate. An economizer heat exchanger is located downstream from an outlet of the heat rejecting heat exchanger and upstream from the expansion device relative to a flow of the refrigerant. The economizer heat exchanger has a main flow path and an economizer flow path formed therein. All liquid refrigerant provided at an outlet of the heat rejecting heat exchanger is provided to the main flow path.

What is claimed is: 
     
         1 . A refrigeration system comprising:
 a compressor, a heat rejecting heat exchanger, an expansion device, and a heat absorbing heat exchanger fluidly connected to form a closed loop through which a refrigerant is configured to circulate;   an economizer heat exchanger located downstream from an outlet of the heat rejecting heat exchanger and upstream from the expansion device relative to a flow of the refrigerant, the economizer heat exchanger having a main flow path and an economizer flow path formed therein, wherein all liquid refrigerant provided at an outlet of the heat rejecting heat exchanger is provided to the main flow path.   
     
     
         2 . The refrigeration system of  claim 1 , wherein a portion of the refrigerant is provided to the main flow path and the economizer flow path in series. 
     
     
         3 . The refrigeration system of  claim 1 , further comprising a subcooler arranged directly downstream from and in fluid communication with the heat rejecting heat exchanger, wherein an outlet of the subcooler is fluidly connected to an inlet of the main flow path. 
     
     
         4 . The refrigeration system of  claim 3 , wherein all the liquid refrigerant provided at the outlet of the subcooler is provided to the main flow path. 
     
     
         5 . The refrigeration system of  claim 1 , wherein the expansion device and the economizer flow path are arranged in parallel relative to an outlet of the main flow path. 
     
     
         6 . The refrigeration system of  claim 5 , wherein the compressor includes a primary suction inlet and an economizer suction inlet, the heat absorbing heat exchanger being fluidly connected to the primary suction inlet and the economizer flow path being fluidly connected to the economizer suction inlet. 
     
     
         7 . The refrigeration system of  claim 5 , further comprising an economizer expansion device arranged downstream from the outlet of the main flow path and directly upstream from the economizer flow path. 
     
     
         8 . The refrigeration system of  claim 1 , wherein an inlet of the main flow path is arranged at a first side of the economizer heat exchanger and an inlet of the economizer flow path is arranged at a second, opposite side of the economizer heat exchanger. 
     
     
         9 . A refrigeration system comprising:
 a compressor, a heat rejecting heat exchanger, an expansion device, and a heat absorbing heat exchanger fluidly connected to form a closed loop through which a refrigerant is configured to circulate;   an economizer heat exchanger located downstream from an outlet of the heat rejecting heat exchanger and upstream from the expansion device relative to a flow of the refrigerant, the economizer heat exchanger having a main flow path and an economizer flow path formed therein, wherein an inlet of the economizer flow path is fluidly coupled to an outlet of the main flow path such that a portion of the refrigerant is provided to the main flow path and the economizer flow path in series.   
     
     
         10 . The refrigeration system of  claim 9 , wherein all liquid refrigerant output from the heat rejecting heat exchanger is provided to the main flow path. 
     
     
         11 . The refrigeration system of  claim 9 , wherein the expansion device and the economizer flow path are arranged in parallel relative to the outlet of the main flow path. 
     
     
         12 . The refrigeration system of  claim 11 , wherein the compressor includes a primary suction inlet and an economizer suction inlet, the heat absorbing heat exchanger being fluidly connected to the primary suction inlet and the economizer flow path being fluidly connected to the economizer suction inlet. 
     
     
         13 . The refrigeration system of  claim 11 , further comprising an economizer expansion device arranged downstream from the outlet of the main flow path and directly upstream from the economizer flow path. 
     
     
         14 . The refrigeration system of  claim 9 , further comprising a subcooler arranged directly downstream from and in fluid communication with the heat rejecting heat exchanger, wherein an outlet of the subcooler is fluidly connected to an inlet of the main flow path. 
     
     
         15 . The refrigeration system of  claim 14 , wherein all of the liquid refrigerant provided at the outlet of the subcooler is provided to the main flow path. 
     
     
         16 . The refrigeration system of  claim 9 , wherein an inlet of the main flow path is arranged at a first side of the economizer heat exchanger and the inlet of the economizer flow path is arranged at a second, opposite side of the economizer heat exchanger. 
     
     
         17 . A method of operating a refrigeration system, the method comprising:
 condensing and cooling a refrigerant;   further cooling the refrigerant within a main flow path of an economizer heat exchanger;   separating the refrigerant at an outlet of the main flow path into a first portion and a second portion; and   heating the second portion of the refrigerant provided within an economizer flow path of the economizer heat exchanger.   
     
     
         18 . The method of  claim 17 , wherein the condensing and cooling occurs within a subcooler and all liquid refrigerant at the outlet of the subcooler is provided to the main flow path. 
     
     
         19 . The method of  claim 17 , further comprising lowering an enthalpy of the second portion of the refrigerant, wherein lowering the enthalpy occurs prior to heating the second portion of the refrigerant within the economizer flow path. 
     
     
         20 . The method of  claim 17 , further comprising providing the first portion of the refrigerant at the outlet of the main flow path to an expansion device and a heat absorbing heat exchanger in series.