Thermal transfer device and working fluid therefor including a kinetic ice inhibitor

Abstract

A kinetic ice inhibitor is added to water in very small quantities (0.5 to 1.0 wt. %) to inhibit the nucleation and growth of ice crystals when the water is used as a working fluid in a heat transfer device, such as a vapor chamber heat sink. The preferred type of kinetic ice inhibitor is a water soluble polymer or copolymer, such as polymers, copolymers of polyvinylpyrrolidone (PVP) and polyvinylcaprolactam (PVCAP) and terpolymers VC-713. These polymers kinetically delay or inhibit the formation and growth of ice crystals in the water and significantly reduce the chances of expansion damage to the heat transfer device when subjected to below freezing temperatures potentially encountered during shipment and storage.

What is claimed is:  
     
         1 . A working fluid for use in a thermal transfer device comprising: 
 water; and    a kinetic ice inhibitor in an amount effective to kinetically inhibit the nucleation and growth of ice crystals within said water when said working fluid is subjected to temperatures below 0° C.    
     
     
         2 . The working fluid of  claim 1  wherein said kinetic ice inhibitor comprises a substantially water-soluble polymer.  
     
     
         3 . The working fluid of  claim 2  wherein said polymer is present in an amount of from about 0.01 percent to about 1.5 percent by weight relative to the total fluid weight.  
     
     
         4 . The working fluid of  claim 3  wherein said polymer is present in an amount of from about 0.5 percent to about 1.0 percent by weight relative to the total fluid weight.  
     
     
         5 . The working fluid of  claim 2  wherein said polymer has the following formula  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a pendant group having an amid group (N—C═O) adjacent to the polymer backbone, and n is a whole number greater than 1.  
     
     
         6 . The working fluid of  claim 5  wherein said pendant group is a lactam ring.  
     
     
         7 . The working fluid of  claim 2  wherein said polymer is a copolymer having the following formula  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a first pendant group having an amid group (N—C═O) adjacent to the polymer backbone, R 2  is a second pendant group having an amid group (N—C═O) adjacent to the polymer backbone, and x and y are whole numbers greater than 1.  
     
     
         8 . The working fluid of  claim 2  wherein said polymer is a terpolymer having the following formula  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a first pendant group having an amid group (N—C═O) adjacent to the polymer backbone, R 2  is a second pendant group having an amid group (N—C═O) adjacent to the polymer backbone, R 3  is a third pendant group having a amino group (O—C═O) adjacent the polymer backbone, and x, y, and z are whole numbers greater than 1.  
     
     
         9 . The working fluid of  claim 2  wherein said polymer is selected from the group consisting of: polymers, copolymers and terpolymers of polyvinylcaprolactam (PVCAP) and polyvinylpyrrolidone (PVP).  
     
     
         10 . The working fluid of  claim 2  wherein said polymer is selected from the group consisting of: polyvinylpyrrolidone (PVP), polyvinylcaprolactam (PVCAP), poly(vinylpyrrolidone-vinylcaprolactam) (VPNC), and poly(vinylpyrrolidone-vinylcaprolactam-dimethylaminoethyl) (VC-713).  
     
     
         11 . A heat transfer device comprising: 
 a vacuum sealed vapor chamber having an evaporator section and a condenser section;    a working fluid contained within said vapor chamber, said working fluid comprising: 
 water; and  
 a kinetic ice inhibitor in an amount effective to kinetically inhibit the nucleation and growth of ice crystals within said working fluid when said working fluid is subjected to temperatures below 0° C.  
   
     
     
         12 . The heat transfer device of  claim 11  wherein said kinetic ice inhibitor comprises a substantially water-soluble polymer.  
     
     
         13 . The heat transfer device of  claim 12  wherein said polymer is present in an amount of from about 0.01 percent to about 1.5 percent by weight relative to the total fluid weight.  
     
     
         14 . The heat transfer device of  claim 13  wherein said polymer is present in an amount of from about 0.5 percent to about 1.0 percent by weight relative to the total fluid weight.  
     
     
         15 . The heat transfer device of  claim 12  wherein said polymer has the following formula  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a pendant group having an amid group (N—C═O) adjacent to the polymer backbone, and n is a whole number greater than 1.  
     
     
         16 . The heat transfer device of  claim 15  wherein said pendant group is a lactam ring.  
     
     
         17 . The heat transfer device of  claim 12  wherein said polymer is a copolymer having the following formula  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a first pendant group having an amid group (N—C═O) adjacent to the polymer backbone, R 2  is a second pendant group having an amid group (N—C═O) adjacent to the polymer backbone, and x and y are whole numbers greater than 1.  
     
     
         18 . The heat transfer device of  claim 12  wherein said polymer is a terpolymer having the following formula  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a first pendant group having an amid group (N—C═O) adjacent to the polymer backbone, R 2  is a second pendant group having an amid group (N—C═O) adjacent to the polymer backbone, R 3  is a third pendant group having a amino group (O—C═O) adjacent the polymer backbone, and x, y, and z are whole numbers greater than 1.  
     
     
         19 . The heat transfer device of  claim 2  wherein said polymer is selected from the group consisting of: polymers, copolymers and terpolymers of polyvinylcaprolactam (PVCAP) and polyvinylpyrrolidone (PVP).  
     
     
         20 . The heat transfer device of  claim 12  wherein said polymer is selected from the group consisting of: polyvinylpyrrolidone (PVP), polyvinylcaprolactam (PVCAP), poly(vinylpyrrolidone-vinylcaprolactam) (VPNC), and poly(vinylpyrrolidone-vinylcaprolactam-dimethylaminoethyl) (VC-713).  
     
     
         21 . A semiconductor assembly comprising: 
 a semiconductor device;    a vapor chamber heat sink having a vacuum sealed vapor chamber, 
 said vapor chamber having an evaporator section in thermal communication with said semiconductor device and further having a condenser section;  
   a working fluid contained within said vapor chamber, said working fluid comprising: 
 water; and  
 a kinetic ice inhibitor in an amount effective to kinetically inhibit the nucleation and growth of ice crystals within said working fluid when said working fluid is subjected to temperatures below 0° C.  
   
     
     
         22 . The semiconductor assembly of  claim 21  wherein said kinetic ice inhibitor comprises a substantially water-soluble polymer.  
     
     
         23 . The semiconductor assembly of  claim 22  wherein said polymer is present in an amount of from about 0.01 percent to about 1.5 percent by weight relative to the total fluid weight.  
     
     
         24 . The semiconductor assembly of  claim 23  wherein said polymer is present in an amount of from about 0.5 percent to about 1.0 percent by weight relative to the total fluid weight.  
     
     
         25 . The semiconductor assembly of  claim 22  wherein said polymer has the following formula  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a pendant group having an amid group (N—C═O) adjacent to the polymer backbone, and n is a whole number greater than 1.  
     
     
         26 . The semiconductor assembly of  claim 25  wherein said pendant group is a lactam ring.  
     
     
         27 . The semiconductor assembly of  claim 12  wherein said polymer is a copolymer having the following formula  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a first pendant group having an amid group (N—C═O) adjacent to the polymer backbone, R 2  is a second pendant group having an amid group (N—C═O) adjacent to the polymer backbone, and x and y are whole numbers greater than 1.  
     
     
         28 . The semiconductor assembly of  claim 22  wherein said polymer is a terpolymer having the following formula  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a first pendant group having an amid group (N—C═O) adjacent to the polymer backbone, R 2  is a second pendant group having an amid group (N—C═O) adjacent to the polymer backbone, R 3  is a third pendant group having a amino group (O—C═O) adjacent the polymer backbone, and x, y, and z are whole numbers greater than 1.  
     
     
         29 . The semiconductor assembly of  claim 22  wherein said polymer is selected from the group consisting of: polymers, copolymers and terpolymers of polyvinylcaprolactam (PVCAP) and polyvinylpyrrolidone (PVP).  
     
     
         30 . The semiconductor assembly of  claim 22  wherein said polymer is selected from the group consisting of: polyvinylpyrrolidone (PVP), polyvinylcaprolactam (PVCAP), poly(vinylpyrrolidone-vinylcaprolactam) (VPNC), and poly(vinylpyrrolidone-vinylcaprolactam-dimethylaminoethyl) (VC-7 13).  
     
     
         31 . A method of inhibiting the nucleation and growth of ice crystals in a water-based working fluid to be used in a heat transfer device, said method comprising: 
 treating said working fluid with a kinetic ice inhibitor comprising a substantially water-soluble polymer.    
     
     
         32 . The method of  claim 31  wherein said polymer is present in an amount of from about 0.01 percent to about 1.5 percent by weight relative to the total fluid weight.  
     
     
         33 . The method of  claim 32  wherein said polymer is present in an amount of from about 0.5 percent to about 1.0 percent by weight relative to the total fluid weight.  
     
     
         34 . The method of  claim 31  wherein said polymer has the following formula  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a pendant group having an amid group (N—C═O) adjacent to the polymer backbone, and n is a whole number greater than 1.  
     
     
         35 . The method of  claim 34  wherein said pendant group is a lactam ring.  
     
     
         36 . The method of  claim 31  wherein said polymer is a copolymer having the following formula  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a first pendant group having an amid group (N—C═O) adjacent to the polymer backbone, R 2  is a second pendant group having an amid group (N—C═O) adjacent to the polymer backbone, and x and y are whole numbers greater than 1.  
     
     
         37 . The method of  claim 31  wherein said polymer is a terpolymer having the following formula  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a first pendant group having an amid group (N—C═O) adjacent to the polymer backbone, R 2  is a second pendant group having an amid group (N—C═O) adjacent to the polymer backbone, R 3  is a third pendant group having a amino group (O—C═O) adjacent the polymer backbone, and x, y, and z are whole numbers greater than 1.  
     
     
         38 . The method of  claim 31  wherein said polymer is selected from the group consisting of: polymers, copolymers and terpolymers of polyvinylcaprolactam (PVCAP) and polyvinylpyrrolidone (PVP).  
     
     
         39 . The method of  claim 31  wherein said polymer is selected from the group consisting of: polyvinylpyrrolidone (PVP), polyvinylcaprolactam (PVCAP), poly(vinylpyrrolidone-vinylcaprolactam) (VPNC), and poly(vinylpyrrolidone-vinylcaprolactam-dimethylaminoethyl) (VC-713).  
     
     
         40 . A working fluid for use in a thermal transfer device comprising: 
 between about 98.5 wt % and about 99.9 wt % water; and    between about 0.1 wt % and about 1.5 wt % of a kinetic ice inhibitor effective to kinetically inhibit the nucleation and growth of ice crystals within said water when said working fluid is subjected to temperatures below 0° C.,    said kinetic ice inhibitor comprising a substantially water-soluble polymer selected from the group consisting of: polyvinylpyrrolidone (PVP), polyvinylcaprolactam (PVCAP), poly(vinylpyrrolidone-vinylcaprolactam) (VPNC), and poly(vinylpyrrolidone-vinylcaprolactam-dimethylaminoethyl) (VC-7 13).    
     
     
         41 . The working fluid of  claim 40  wherein said polymer is present in an amount of from about 0.5 percent to about 1.0 percent by weight relative to the total fluid weight.  
     
     
         42 . A heat transfer device comprising: 
 a vacuum sealed vapor chamber having an evaporator section and a condenser section;    a working fluid contained within said vapor chamber, said working fluid comprising: 
 between about 98.5 wt % and about 99.9 wt % water, and between about 0.1 wt % and about 1.5 wt % of a kinetic ice inhibitor effective to kinetically inhibit the nucleation and growth of ice crystals within said water when said working fluid is subjected to temperatures below 0° C.,  
   said kinetic ice inhibitor comprising a substantially water-soluble polymer selected from the group consisting of: polyvinylpyrrolidone (PVP), polyvinylcaprolactam (PVCAP), poly(vinylpyrrolidone-vinylcaprolactam) (VPNC), and poly(vinylpyrrolidone-vinylcaprolactam-dimethylaminoethyl) (VC-713).    
     
     
         43 . The heat transfer device of  claim 41  wherein said polymer is present in an amount of from about 0.5 percent to about 1.0 percent by weight relative to the total fluid weight.  
     
     
         44 . The heat transfer device of  claim 42  further comprising a finned heat sink structure in thermal communication with said evaporator section of said vapor chamber.  
     
     
         45 . The heat transfer device of  claim 42  wherein said working fluid is present in said vapor chamber in an amount between about 5% and about 25% by volume of a total volume of said vapor chamber.