Passive refrigeration system for the cold chain industry

Abstract

A passive refrigeration box for controlled refrigeration of a product comprising: an outer box including an outer insulation layer; an inner box including an inner insulation layer, and a thermal shield on an outside of the inner insulation layer, the inner box and the outer box defining a vapour channel therebetween; and a thermal link including a thermal layer and a plurality of heat pipes or thermosyphons, the thermal layer and a top section of the inner box defining a coolant chamber, the coolant chamber including a coolant chamber access, and in communication with the vapour channel, and the thermal layer and a bottom section of the inner box defining a load chamber, the load chamber including a load chamber access, each heat pipe or thermosyphon having a condenser section disposed in the coolant chamber and an evaporator section disposed in the load chamber and extending through the thermal layer.

1 . A passive refrigeration box for controlled refrigeration of a product, the refrigeration box comprising:
 an outer box, the outer box including an outer insulation layer;   an inner box, the inner box including an inner insulation layer, and a thermal shield on an outside of the inner insulation layer, the inner box and the outer box defining a vapour channel therebetween; and   a thermal link, the thermal link including a thermal layer and a plurality of heat pipes or a plurality of thermosyphons, the thermal layer and a top section of the inner box defining a coolant chamber, the coolant chamber including a coolant chamber access, and the coolant chamber in communication with the vapour channel, and the thermal layer and a bottom section of the inner box defining a load chamber, the load chamber including a load chamber access, each heat pipe or thermosyphon having a condenser section disposed in the coolant chamber and an evaporator section disposed in the load chamber and extending through the thermal layer.   
     
     
         2 . The passive refrigeration box of  claim 1 , further comprising a mesh header below the plurality of heat pipes or the plurality of thermosyphons. 
     
     
         3 . The passive refrigeration box of  claim 1 , further comprising an outer skin on the outer insulation and an inner liner on the inner insulation. 
     
     
         4 . The passive refrigeration system of  claim 1 , wherein the thermal link includes the plurality of heat pipes. 
     
     
         5 . The passive refrigeration box of  claim 1 , wherein the thermal shield is an aluminum shield. 
     
     
         6 . The passive refrigeration box of  claim 1 , wherein the coolant chamber access includes an outer lid and an inner lid. 
     
     
         7 . The passive refrigeration box of  claim 6 , wherein the inner lid is seated on a step in the inner box. 
     
     
         8 . The passive refrigeration box of  claim 1 , further comprising a gasket between an inner lid and a step in the inner box. 
     
     
         9 . The passive refrigeration box of  claim 1 , wherein the plurality of heat pipes are weld-free heat pipes. 
     
     
         10 . The passive refrigeration box of  claim 9 , wherein the plurality of heat pipes include a working fluid, the working fluid selected from a group consisting of acetone, methanol, pentane, and propylene. 
     
     
         11 . The passive refrigeration box of  claim 1 , wherein the thermal link is a reconfigurable thermal link. 
     
     
         12 . The passive refrigeration box of  claim 6 , further comprising a check valve in the outer lid, wherein the check valve is in communication with the vapour channel. 
     
     
         13 . A passive refrigeration system for the cold-chain industry, the system including:
 a box and a solid coolant, the box comprising:
 an outer box, the outer box including an outer insulation layer, 
 an inner box, the inner box including an inner insulation layer, and 
 a thermal shield on an outside of the inner insulation layer, the inner box and the outer box defining a vapour channel therebetween; and 
 a thermal link, the thermal link including a thermal layer and a plurality of heat pipes or a plurality of thermosyphons, the thermal layer and a top of the inner box defining a coolant chamber, the coolant chamber including a coolant chamber access, and the coolant chamber in communication with the vapour channel, and the thermal layer and a bottom of the inner box defining a load chamber, the load chamber including a load chamber access, each heat pipe of the plurality of heat pipes or thermosyphon of the plurality of thermosyphons having a condenser section disposed in the coolant chamber and an evaporator section disposed in the load chamber and extending through the thermal layer, and where the solid coolant is solid carbon dioxide. 
   
     
     
         14 . The system of  claim 13 , wherein the thermal link is a reconfigurable thermal link. 
     
     
         15 . The system of  claim 13 , wherein the thermal link includes the plurality of heat pipes. 
     
     
         16 . The system of  claim 13 , wherein the heat pipes are weld-free heat pipes. 
     
     
         17 . The system of  claim 16 , wherein the heat pipes include a working fluid, the working fluid selected from a group consisting of acetone, methanol, pentane, and propylene. 
     
     
         18 . The system of  claim 13 , wherein the thermal shield is an aluminum shield. 
     
     
         19 . A passive refrigeration box for controlled refrigeration of a product, the refrigeration box comprising:
 a bottom;   four sides attached to the bottom;   an inner lid; and   an outer lid, the sides including an outer insulation layer and an inner insulation layer, the layers and the inner and outer lids defining a vapour channel therebetween, an aluminum shield adjacent the vapour channel and abutting an outer side of the inner insulation layer and a top of the inner lid;   a thermal layer, the thermal layer disposed below the inner lid and between the inner insulation layers to define a coolant chamber, the coolant chamber for retaining a coolant and in communication with the vapour channel; and   a load chamber, the load chamber defined by the inner insulation layer and the thermal layer; and   a plurality of heat pipes, each heat pipe of the plurality of heat pipes having a condenser section disposed in the coolant chamber and an evaporator section disposed in the load chamber and extending through the thermal layer.   
     
     
         20 . A method of refrigerating a load passively, using the refrigeration box of  claim 1 , the method comprising loading the load into the load chamber and charging the coolant chamber with a solid coolant. 
     
     
         21 . The method of  claim 20 , further comprising configuring the thermal link to regulate the temperature of the load. 
     
     
         22 . The method of  claim 20 , wherein the solid coolant is solid carbon dioxide.