Systems and methods for purging a chiller system

Abstract

Embodiments of the present disclosure relate to a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system including a refrigerant loop and a purge system configured to purge the HVAC&R system of non-condensable gases. The purge system includes a liquid pump configured to draw a first refrigerant flow from an evaporator, a controllable expansion valve configured to receive the first refrigerant flow from the liquid pump and reduce a temperature of the first refrigerant flow, and a purge heat exchanger, which includes a purge coil. The purge coil is configured to receive the first refrigerant flow from the controllable expansion valve, a chamber of the purge heat exchanger is configured to draw a mixture of the non-condensable gases and a second refrigerant flow from a condenser, and the purge heat exchanger is configured to separate the non-condensable gases from the second refrigerant flow utilizing the first refrigerant flow.

1 . A heating, ventilation, air conditioning, and refrigeration (HVAC&R) system, comprising:
 a refrigerant loop;   a compressor disposed along the refrigerant loop, wherein the compressor configured to circulate refrigerant through the refrigerant loop;   an evaporator disposed along the refrigerant loop, wherein the evaporator is configured to place the refrigerant in a heat exchange relationship with a first cooling fluid;   a condenser disposed along the refrigerant loop, wherein the condenser is configured to place the refrigerant in a heat exchange relationship with second cooling fluid; and   a purge system configured to purge the HVAC&R system of non-condensable gases, the purge system comprising:
 a liquid pump configured to draw a first refrigerant flow from the evaporator; 
 an controllable expansion valve configured to receive the first refrigerant flow from the liquid pump and reduce a temperature of the first refrigerant flow; and 
 a purge heat exchanger comprising a purge coil, wherein the purge coil is configured to receive the first refrigerant flow from the controllable expansion valve, wherein a chamber of the purge heat exchanger is configured to draw a mixture comprising the non-condensable gases and a second refrigerant flow from the condenser, and wherein the purge heat exchanger is configured to separate the non-condensable gases of the mixture from the second refrigerant flow of the mixture utilizing the first refrigerant flow. 
   
     
     
         2 . The HVAC&R system of  claim 1 , comprising an ejector configured to receive the first refrigerant flow from the purge coil, wherein the ejector is configured to increase the pressure of first refrigerant flow utilizing the second refrigerant flow from the condenser. 
     
     
         3 . The HVAC&R system of  claim 2 , wherein the evaporator is configured to receive the second refrigerant flow and the first refrigerant flow discharged from the ejector. 
     
     
         4 . The HVAC&R system of  claim 1 , wherein the purge system further comprises a pump configured to remove the non-condensable gases of the mixture from the purge heat exchanger. 
     
     
         5 . The HVAC&R system of  claim 1 , wherein the purge system further comprises a conduit configured to flow the first refrigerant flow from the liquid pump to the controllable expansion valve, and wherein one or more thermoelectric assemblies are coupled to the conduit and configured to remove thermal energy from the first refrigerant flow flowing through the conduit. 
     
     
         6 . The HVAC&R system of  claim 5 , wherein each thermoelectric assembly of the one or more thermoelectric assemblies is configured to remove thermal energy of the first refrigerant flow by converting an electrical power gradient to a thermal gradient. 
     
     
         7 . The HVAC&R system of  claim 1 , wherein the purge system further comprises one or more adsorption chambers configured to receive the mixture from the purge heat exchanger, and wherein each adsorption chamber of the one or more adsorption chambers is configured to separate the non-condensable gases of the mixture from the second refrigerant flow of the mixture. 
     
     
         8 . The HVAC&R system of  claim 7 , wherein the one or more adsorption chambers is configured to expel the non-condensable gases of the mixture into the atmosphere and flow the second refrigerant flow of the mixture to the evaporator. 
     
     
         9 . The HVAC&R system of  claim 1 , wherein the liquid pump is configured to draw the first refrigerant flow from the evaporator through a flash tank, wherein the first refrigerant flow drawn from the evaporator comprises refrigerant liquid and refrigerant vapor, and wherein the flash tank is configured to separate the refrigerant liquid from the refrigerant vapor. 
     
     
         10 . The HVAC&R system of  claim 9 , wherein the flash tank is configured to flow the refrigerant liquid to the liquid pump and flow refrigerant vapor to the evaporator. 
     
     
         11 . The HVAC&R system of  claim 1 , wherein the purge heat exchanger is configured to flow the second refrigerant flow of the mixture into the condenser, the evaporator, or both. 
     
     
         12 . A heating, ventilation, air conditioning, and refrigeration (HVAC&R) system comprising:
 a refrigerant loop;   a compressor disposed along the refrigerant loop and configured to circulate refrigerant through the refrigerant loop;   an evaporator disposed along the refrigerant loop and configured to place the refrigerant in a heat exchange relationship with a first cooling fluid;   a condenser disposed along the refrigerant loop and configured to place the refrigerant in a heat exchange relationship with a second cooling fluid; and   a purge system configured to purge the HVAC&R system of non-condensable gases (NCG), the purge system comprising:
 a purge heat exchanger configured to separate a mixture drawn from the condenser utilizing a first refrigerant flow of the refrigerant drawn from the evaporator, wherein the mixture comprises the NCG and a second refrigerant flow of the refrigerant from the condenser, and wherein separating the mixture comprises separating the NCG from the second refrigerant flow; and 
 one or more thermoelectric assemblies configured to remove thermal energy from the second refrigerant flow. 
   
     
     
         13 . The HVAC&R system of  claim 12 , wherein the purge system further comprises a liquid pump configured to draw the first refrigerant flow from the evaporator and push the first refrigerant flow through the one or more thermoelectric assemblies to the purge heat exchanger. 
     
     
         14 . The HVAC&R system of  claim 13 , wherein the purge system further comprises a conduit configured to flow the first refrigerant flow from the liquid pump to the purge heat exchanger, and wherein the one or more thermoelectric assemblies are coupled to the conduit. 
     
     
         15 . The HVAC&R system of claim of  claim 14 , wherein each thermoelectric assembly of the one or more thermoelectric assemblies comprises:
 thermal paste configured to couple the thermoelectric assembly to the conduit;   a thermoelectric assembly coupled to the thermal paste and configured to remove thermal energy from the first refrigerant flow by converting an electrical power gradient to a thermal gradient;   a heat sink coupled to the thermoelectric assembly; and   a fan coupled to the heat sink.   
     
     
         16 . The HVAC&R system of  claim 12 , wherein the purge heat exchanger comprises a purge coil configured to receive the first refrigerant flow. 
     
     
         17 . The HVAC&R system of  claim 12 , wherein the purge system further comprises a pump configured to remove the NCG from the purge heat exchanger. 
     
     
         18 . The HVAC&R system of  claim 12 , wherein the purge heat exchanger is configured to flow the second refrigerant flow to the condenser, the evaporator, or both. 
     
     
         19 . The HVAC&R system of  claim 12 , wherein the purge system further comprises one or more adsorption chambers configured to receive at least a portion of the mixture from the purge heat exchanger, and wherein the one or more adsorption chambers is configured to separate the second refrigerant flow from the NCG by adsorbing the second refrigerant flow. 
     
     
         20 . A heating, ventilation, air conditioning, and refrigeration (HVAC&R) system comprising:
 a refrigerant loop;   a compressor disposed along the refrigerant loop and configured to circulate refrigerant through the refrigerant loop;   an evaporator disposed along the refrigerant loop and configured to place the refrigerant in a heat exchange relationship with a first cooling fluid;   a condenser disposed along the refrigerant loop and configured to place the refrigerant in a heat exchange relationship with second cooling fluid; and   a purge system configured to purge the HVAC&R system of non-condensable gases (NCG), the purge system comprising:   a purge heat exchanger configured to separate a mixture drawn from the condenser utilizing a first refrigerant flow of the refrigerant drawn from the evaporator, wherein the mixture comprises the NCG and a second refrigerant flow of the refrigerant from the condenser, and wherein separating the mixture comprises separating the NCG from the second refrigerant flow; and   one or more adsorption chambers configured to receive the NCG from the purge heat exchanger, wherein the one or more adsorption chambers is configured to separate the NCG from remaining refrigerant.   
     
     
         21 . The HVAC&R system of  claim 20 , wherein each of the one or more adsorption chambers comprises a modified material configured to adsorb the remaining refrigerant and allow the NCG to pass through the one or more adsorption chambers. 
     
     
         22 . The HVAC&R system of  claim 21 , wherein each of the one or more adsorption chambers comprises a heater configured to heat the modified material to expel the remaining refrigerant from the modified material. 
     
     
         23 . The HVAC&R system of  claim 20 , wherein the evaporator is configured to receive the remaining refrigerant from the one or more adsorption chambers. 
     
     
         24 . The HVAC&R system of  claim 20 , wherein the one or more adsorption chambers is configured to expel the NCG into the atmosphere. 
     
     
         25 . The HVAC&R system of  claim 20 , wherein the purge system further comprises:
 a pump configured to draw the NCG from the purge heat exchanger, wherein the one or more adsorption chambers is configured to receive the NCG from the pump;   a liquid pump configured to draw the first refrigerant flow from the evaporator;   a controllable expansion valve configured to receive the first refrigerant flow from the liquid pump and decrease a pressure of the first refrigerant flow; and   a purge coil of the purge heat exchanger configured to receive the first refrigerant flow from the controllable expansion valve; wherein a chamber of the purge heat exchanger enables the mixture to exchange heat with the first refrigerant flow within the purge coil.   
     
     
         26 . The HVAC&R system of  claim 25 , wherein the purge system further comprises one or more thermoelectric assemblies configured to remove thermal energy from the first refrigerant flow exiting the liquid pump by converting an electrical power gradient into a thermal gradient. 
     
     
         27 . A heating, ventilation, air conditioning, and refrigeration (HVAC&R) system, comprising:
 a purge system configured to purge a vapor compression system of non-condensable gases (NCG), comprising:
 a pump configured to draw a mixture, comprising vapor refrigerant and the NCG, from a condenser of the vapor compression system; and 
 a purge heat exchanger configured to receive the mixture from the pump and place the mixture in a heat exchange relationship with a refrigerant flow drawn from the vapor compression system to condense the vapor refrigerant of the mixture and separate the NCG of the mixture from the vapor refrigerant, 
 wherein the pump is configured to increase a pressure of the mixture to induce flow of the NCG from the purge heat exchanger into the atmosphere via a pressure differential between the NCG and the atmosphere. 
   
     
     
         28 . The HVAC&R system of  claim 27 , comprising a liquid pump configured to draw the refrigerant flow from the vapor compression system and provide the refrigerant flow to the purge heat exchanger. 
     
     
         29 . The HVAC&R system of  claim 28 , wherein the purge heat exchanger is a direct contact heat exchanger. 
     
     
         30 . The HVAC&R system of  claim 27 , comprising an expansion device disposed along a conduit extending from a refrigerant loop of the vapor compression system to the purge heat exchanger, wherein the conduit and the expansion device are configured to supply the refrigerant flow to the purge heat exchanger. 
     
     
         31 . The HVAC&R system of  claim 30 , wherein the expansion device is configured to lower a pressure of the refrigerant flow to induce flow of the refrigerant flow through the purge heat exchanger and back to the vapor compression system via a second pressure differential between the refrigerant flow and an evaporator of the vapor compression system. 
     
     
         32 . The HVAC&R system of  claim 27 , comprising an ejector configured to draw the refrigerant flow from the purge heat exchanger and direct the refrigerant flow to an evaporator of the vapor compression system.