Carbon Dioxide Based Auxiliary Cooling System

Abstract

The present application provides a cascade refrigeration system. The cascade refrigeration system may include a first side cycle, a second side cycle with a second side cycle carbon dioxide refrigerant, and an auxiliary cooling system to cool the second side cycle carbon dioxide refrigerant in the event of a power outage. The auxiliary cooling system may include an auxiliary carbon dioxide refrigerant.

We claim: 
     
         1 . A cascade refrigeration system, comprising:
 a first side cycle;   a second side cycle;   the second side cycle comprising a second side cycle carbon dioxide refrigerant; and   an auxiliary cooling system to cool the second side cycle carbon dioxide refrigerant in the event of a power outage;   the auxiliary cooling system comprising an auxiliary carbon dioxide refrigerant.   
     
     
         2 . The cascade refrigeration system of  claim 1 , wherein the auxiliary cooling system comprises an auxiliary compressor and an auxiliary expansion valve. 
     
     
         3 . The cascade refrigeration system of  claim 1 , wherein the auxiliary cooling system comprises an auxiliary condenser. 
     
     
         4 . The cascade refrigeration system of  claim 1 , wherein the auxiliary cooling system comprises an auxiliary gas cooler. 
     
     
         5 . The cascade refrigeration system of  claim 1 , wherein the auxiliary cooling system comprises auxiliary condenser/evaporator. 
     
     
         6 . The cascade refrigeration system of  claim 1 , wherein the second side cycle comprises a second side cycle receiver and wherein the auxiliary cooling system is in communication with the second side cycle receiver. 
     
     
         7 . The cascade refrigeration system of  claim 1 , wherein the auxiliary cooling system comprises an auxiliary generator. 
     
     
         8 . The cascade refrigeration system of  claim 1 , wherein the first side cycle and the second side cycle interface via a cascade evaporator/condenser. 
     
     
         9 . The cascade refrigeration system of  claim 1 , wherein the first side cycle comprises a flow of an ammonia or a hydrocarbon refrigerant. 
     
     
         10 . The cascade refrigeration system of  claim 1 , wherein the first side comprises a suction/liquid heat exchanger. 
     
     
         11 . The cascade refrigeration system of  claim 1 , wherein the first side cycle comprises a first side compressor, a first side condenser, and a first side expansion device. 
     
     
         12 . The cascade refrigeration system of  claim 1 , wherein the second side cycle comprises a second side compressor, a second side expansion device, and a second side evaporator. 
     
     
         13 . The cascade refrigeration system of  claim 1 , wherein the second side cycle comprises a medium temperature loop and a medium temperature loop. 
     
     
         14 . The cascade refrigeration system of  claim 1 , further comprising a plurality of auxiliary cooling systems. 
     
     
         15 . An method of providing auxiliary cooling in a refrigeration system, comprising:
 flowing a natural refrigerant through a first side cycle;   flowing a carbon dioxide refrigerant through a second side cycle;   providing an auxiliary cooling system to cool the flow of the carbon dioxide refrigerant in the case of a power loss; and   flowing an auxiliary carbon dioxide refrigerant through the auxiliary cooling system.   
     
     
         16 . A carbon dioxide based refrigeration system, comprising:
 a receiver;   a carbon dioxide refrigerant; and   an auxiliary cooling system in communication with the receiver to cool the carbon dioxide refrigerant in the event of a power outage;   the auxiliary cooling system comprising an auxiliary carbon dioxide refrigerant.   
     
     
         17 . The carbon dioxide refrigeration system of  claim 16 , wherein the auxiliary cooling system comprises an auxiliary condenser. 
     
     
         18 . The carbon dioxide refrigeration system of  claim 16 , wherein the auxiliary cooling system comprises an auxiliary gas cooler. 
     
     
         19 . The carbon dioxide refrigeration system of  claim 16 , wherein the auxiliary cooling system comprises an auxiliary generator. 
     
     
         20 . The carbon dioxide refrigeration system of  claim 16 , wherein the carbon dioxide refrigeration system comprises a cascade refrigeration system.