Closed Loop Ice Slurry Refrigeration System

Abstract

A closed loop refrigeration system comprises an ice slurry mixture which comprises ice, water, and a freezing point depressant. The system also comprises a first storage device for storing the ice slurry mixture, and an agitator disposed in the first storage device. The agitator agitates the ice slurry mixture in at least an intermittent manner. The system further comprises a first conduit connecting the first storage device and a heat load, and a first pump disposed on the first conduit for pumping the ice slurry mixture through the first conduit from the first storage device to the heat load. At least some of the ice melts in the heat load. The system also comprises a second conduit connecting the heat load and a second storage device. The second storage device is connected to the first storage device. The system further comprises a second pump disposed on the second conduit for pumping the ice slurry mixture containing the melted ice through the second conduit from the heat load to the second storage device.

What Is claimed: 
     
         1 . A closed loop refrigeration system, comprising:
 an ice slurry mixture comprising ice, water, and a freezing point depressant; a first storage device for storing the ice slurry mixture;   an agitator disposed in the first storage device, wherein the agitator agitates the ice slurry mixture in at least an intermittent manner;   a first conduit connecting the first storage device and a heat load;   a first pump disposed on the first conduit for pumping the ice slurry mixture through the first conduit from the first storage device to the heat load, wherein at least some of the ice melts in the heat load;   a second conduit connecting the heat load and a second storage device, the second storage device connected to the first storage device; and   a second pump disposed on the second conduit for pumping the ice slurry mixture containing the melted ice through the second conduit from the heat load to the second storage device.   
     
     
         2 . The system of  claim 1 , where the freezing point depressant comprises a low carbon glycol or the corresponding polyglycol. 
     
     
         3 . The system of  claim 2 , where the low carbon glycol is selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, a corresponding polyglycol, and a mixture thereof. 
     
     
         4 . The system of  claim 2 , where the low carbon glycol is propylene glycol. 
     
     
         5 . The system of  claim 1 , further comprising an ice slurry generator, the ice slurry generator connected to the first and second storage devices. 
     
     
         6 . The system of  claim 1 , further comprising a vibrator disposed on the first or second conduit, the vibrator vibrating the ice slurry mixture contained in the conduit. 
     
     
         7 . A closed loop refrigeration system, comprising:
 an ice slurry mixture comprising about 5-60% ice, about 20-95% water, and about 0-50% a freezing point depressant;   a first storage device for storing the ice slurry mixture;   an agitator disposed in the first storage device, wherein the agitator agitates the ice slurry mixture in at least an intermittent manner;   a heat load;   a first transporter for transporting the ice slurry mixture from the first storage device to the heat load; and   a second transporter for transporting the ice slurry mixture from the heat load to a second storage device, the second storage device connected to the first storage device.   
     
     
         8 . The system of  claim 7 , where the freezing point depressant is propylene glycol. 
     
     
         9 . The system of  claim 7 , where the freezing point depressant is about 10-50% of the ice slurry mixture. 
     
     
         10 . The system of  claim 7 , where the ice is about 20-35% of the ice slurry mixture. 
     
     
         11 . The system of  claim 7 , where the first or second transporter is a pump. 
     
     
         12 . The system of  claim 7 , where the first or second transporter is a progressing cavity pump. 
     
     
         13 . The system of  claim 7 , further comprising an ice slurry generator, the ice slurry generator connected to the first and second storage devices. 
     
     
         14 . The system of  claim 13 , wherein the ice slurry mixture from the heat load is transported to the ice slurry generator for regenerating the ice slurry mixture. 
     
     
         15 . A method, comprising the steps of:
 providing an ice slurry mixture comprising about 5-60% ice, about 20-95% water, and about 0-50% a freezing point depressant in a first storage device;   agitating the ice slurry mixture stored in the first storage device in at least an intermittent manner;   pumping the ice slurry mixture through a first conduit from the first storage device to a heat load, wherein at least some of the ice melts in the heat load;   pumping the ice slurry mixture containing the melted ice through a second conduit from the heat load to a second storage device.   
     
     
         16 . The method of  claim 16 , where the pumping is with a progressing cavity pump. 
     
     
         17 . The method of  claim 16 , further comprising generating the ice slurry mixture and introducing the ice slurry mixture to the first storage device. 
     
     
         18 . The method of  claim 16 , further comprising vibrating the ice slurry mixture contained in the conduit. 
     
     
         19 . The method of  claim 16 , further comprising regenerating the ice slurry mixture containing the melted ice after the ice slurry mixture containing the melted ice is pumped from the heat load to the second storage device.