Gas cooler assembly for transcritical refrigeration system

Abstract

A transcritical refrigeration gas cooler assembly comprises at least one gas cooler-condenser having an inlet and an outlet, the inlet configured to receive a carbon dioxide (CO 2 ) refrigerant from a discharge line of a refrigeration system, at least one evaporator having an inlet and an outlet, the inlet fluidly connected to and downstream of the outlet of the at least one gas cooler-condenser, and an expansion valve positioned upstream of the inlet of at least one evaporator.

1 . A method of operating a transcritical refrigeration gas cooler assembly to recover energy from excess heat, the method comprising:
 receiving a carbon dioxide (CO 2 ) refrigerant at a first refrigerant temperature at an inlet of at least one gas cooler-condenser of the gas cooler assembly;   flowing an external airflow through the gas cooler assembly;   rejecting heat from the CO 2  refrigerant within the at least one gas cooler-condenser to the external airflow to increase an air temperature of the external airflow, wherein rejecting the heat from the CO 2  refrigerant within the at least one gas cooler-condenser to the external airflow generates a microclimate within a microclimate space between the at least one gas-cooler condenser and the at least one evaporator, and downstream of the at least one gas cooler-condenser and upstream of at least one evaporator, relative to a direction of the external airflow through the gas cooler assembly;   initiating a defrost sequence within the at least one gas cooler-condenser by operating the gas cooler-condenser at a maximum discharge gas temperature state;   rejecting heat from the gas cooler-condenser to the microclimate space to warm the microclimate space to above 32° F.; and   defrosting an exterior of the at least one evaporator by the microclimate space.   
     
     
         2 . The method of  claim 1 , wherein the first refrigerant temperature ranges from 88° F. to 300° F. 
     
     
         3 . The method of  claim 1 , wherein flowing the external airflow through the gas cooler assembly comprises: operating at least one fan of the gas cooler assembly to draw the external airflow serially across the at least one gas cooler-condenser and the at least one evaporator. 
     
     
         4 . The method of  claim 3  and further comprising: drawing the external airflow across at least one adiabatic precooler, and operating the adiabatic precooler above a threshold condition of the external airflow. 
     
     
         5 . The method of  claim 1 , and further comprising: throttling a heating output of the gas cooler-condenser to increase a heating capacity of the gas cooler-condenser. 
     
     
         6 . The method of  claim 5  and further comprising: deactivating an outdoor cooling coil to increase heat rejection from the at least one gas cooler-condenser to the microclimate space. 
     
     
         7 . The method of  claim 6  and further comprising: restarting the outdoor cooling coil after the microclimate space has defrosted the at least one evaporator. 
     
     
         8 . A transcritical refrigeration gas cooler assembly comprising:
 a first end and a second end opposite the first end;   at least one gas cooler-condenser comprising an inlet and an outlet, the inlet configured to receive a carbon dioxide (CO 2 ) refrigerant from a discharge line of a refrigeration system, wherein the at least one gas-cooler condenser is between the first end and second end, and wherein the CO 2  refrigerant is at a maximum discharge gas temperature when exiting the at least one gas cooler-condenser at the outlet of the at least one gas cooler-condenser;   at least one evaporator comprising an inlet and an outlet, the inlet of the at least one evaporator is fluidically connected to and downstream of the outlet of the at least one gas cooler-condenser, wherein the at least one evaporator is stacked between the at least on gas cooler-condenser and the first end;   a microclimate space between the at least one evaporator and the at least one gas cooler-condenser; and   an expansion valve positioned upstream of the inlet of at least one evaporator.   
     
     
         9 . The gas cooler assembly of  claim 8  and further comprising: at least one adiabatic precooler. 
     
     
         10 . The gas cooler assembly of  claim 8  and further comprising: at least one fan configured to draw an external airflow into the gas cooler assembly and across the at least one gas cooler-condenser, the microclimate space, and the at least one evaporator. 
     
     
         11 . The gas cooler assembly of  claim 8 , and further comprising: a bypass valve positioned upstream of the inlet of the at least one gas cooler-condenser. 
     
     
         12 . The gas cooler assembly of  claim 8 , wherein an external airflow flows serially across the at least one gas cooler-condenser, the microclimate space, and the at least one evaporator. 
     
     
         13 . The gas cooler assembly of  claim 8 , wherein the at least one gas cooler-condenser receives the CO 2  refrigerant at a first refrigerant temperature ranging from 88° F. to 300° F. 
     
     
         14 . The gas cooler assembly of  claim 8 , wherein the at least one gas cooler assembly is configured as a horizontal gas cooler assembly. 
     
     
         15 . The gas cooler assembly of  claim 8 , wherein the at least one gas cooler assembly is configured as a vertical gas cooler assembly. 
     
     
         16 . The gas cooler assembly of  claim 8 , wherein the at least one gas cooler assembly is configured as a v-bank gas cooler assembly. 
     
     
         17 . The gas cooler assembly of  claim 8 , wherein the at least one gas cooler assembly is configured as an angled gas cooler assembly. 
     
     
         18 . The gas cooler assembly of  claim 8  and further comprising: a damper fluidly connected to a source of auxiliary heat, the damper being configured to allow an amount of the auxiliary heat into the gas cooler assembly between the at least one gas cooler-condenser and the at least one evaporator. 
     
     
         19 . The gas cooler assembly of  claim 18  and further comprising: a bypass valve positioned downstream of the outlet of the at least one evaporator. 
     
     
         20 . The gas cooler assembly of  claim 19 , wherein the at least one evaporator comprises a plurality of evaporators arranged in series.