Phase change materials for enhanced heat transfer fluid performance

Abstract

A composition for enhanced heat transfer fluid performance. The composition includes at least one base heat transfer fluid. The at least one base heat transfer fluid undergoes one or more phase changes in a heat transfer process. The heat transfer process includes a heated zone and/or a cooled zone. The one or more phase changes increase heat removal from the heated zone and/or increase heat rejection in the cooled zone, as compared to heat removal from a heated zone and/or heat rejection in a cooled zone of a heat transfer process having a base heat transfer fluid that does not undergo one or more phase changes. The base heat transfer fluids can exhibit liquid crystal behavior (e.g., heat transfer fluids having nematic, smectic or discotic liquid crystals). A method for conducting heat transfer in a heating and/or cooling system using the compositions comprising the base heat transfer fluids.

1 . A composition for enhanced heat transfer fluid performance, said composition comprising at least one base heat transfer fluid, wherein the at least one base heat transfer fluid undergoes one or more phase changes in a heat transfer process, wherein the heat transfer process comprises a heated zone and/or a cooled zone, wherein the one or more phase changes increase heat removal from the heated zone and/or increase heat rejection in the cooled zone, as compared to heat removal from a heated zone and/or heat rejection in a cooled zone of a heat transfer process having a base heat transfer fluid that does not undergo one or more phase changes. 
     
     
         2 . The composition of  claim 1  wherein the at least one base heat transfer fluid comprises liquid crystals. 
     
     
         3 . The composition of  claim 1  wherein the at least one base heat transfer fluid comprises one or more nematic, smectic or discotic liquid crystals. 
     
     
         4 . The composition of  claim 2  wherein the one or more liquid crystals are represented by the formula:
   R1-(A) m -Y—(B) n —R2
 
 wherein R1 and R2 are the same or different and are a substituted or unsubstituted, alkyl group or alkoxy group having from about 2 to about 24 carbon atoms; 
 A and B are the same or different and are a cycloaliphatic group or aromatic group, provided at least one of A and B is an aromatic group; 
 Y is a covalent bond, —CH2-CH2-, —CH═CH—, —COO—, —CO—, —CSO—, —CSS—, —CS—, —O—, —S—, —SO—, —SO2-, or —CH2O—; and 
 m and n are independently 0, 1, 2 or 3. 
 
     
     
         5 . The composition of  claim 2  wherein the one or more liquid crystals are represented by the formula: 
       
         
           
           
               
               
           
         
       
       or 
     
     
         6 . The composition of  claim 2  wherein the one or more liquid crystals are selected from the group consisting of 4′-n-octyl-4-cyano-biphenyl, 4-(trans-4-heptylcyclohexyl)-pentylbenzene, 4-(trans-4-heptylcyclohexyl)-propylbenzene, and 4-(trans-4-propylcyclohexyl)-ethylbenzene. 
     
     
         7 . The composition of  claim 2  wherein the one or more liquid crystals are represented by the formula: 
       
         
           
           
               
               
           
         
       
     
     
         8 . The composition of  claim 2  wherein the one or more liquid crystals are selected from the group consisting of 4-(hexyloxy)phenyl 4-(heptyloxy)benzoate, 4-pentylphenyl 4-(heptyloxy)benzoate 4-pentylphenyl 4-(heptyloxy)benzoate, 4-(hexyloxy)phenyl 4-(heptyloxy)benzoate and mixture Of them 
     
     
         9 . The composition of  claim 2  wherein the one or more liquid crystals are represented by the formula:
   A-(R3) n    
 
       wherein A is a mono-ring or a multi-ring aromatic group, R3 is the same or different and is a substituted or unsubstituted, hydrocarbon group having from about 2 to about 24 carbon atoms, and n is a value from about 1 to about 12. 
     
     
         10 . The composition of  claim 2  wherein the one or more liquid crystals are represented by the formula: 
       
         
           
           
               
               
           
         
       
     
     
         11 . The composition of  claim 2  wherein the one or more liquid crystals comprise hexakis(octylthio)benzene. 
     
     
         12 . The composition of  claim 1  wherein the at least one base heat transfer fluid has a freezing point of at least greater than about −50° C. as determined by ASTM D1777-17, a boiling point of greater than about 100° C. as determined by ASTM D1120-17, and a flash point of at least 50° C. as determined by ASTM D93-16a. 
     
     
         13 . The composition of  claim 1  further comprising one or more of a corrosion inhibitor, a thermal stabilizer, a pH stabilizer or buffer, an antiscaling agent, a viscosity modifier, or a biocide. 
     
     
         14 . The composition of  claim 1  further comprising one or more lubricating oils to form a bimodal blend, wherein the one or more lubricating oils comprise a Group I, Group II, Group III, Group IV, or Group V oil, and mixtures thereof. 
     
     
         15 . The composition of  claim 1  wherein the heat transfer process is carried out at a temperature and/or pressure sufficient to cause the at least one base heat transfer fluid to undergo one or more phase changes. 
     
     
         16 . The composition of  claim 1  wherein the heat transfer process is carried out at a temperature from about −40° C. to greater than about 80° C., and/or a pressure from about 50 MP to about 500 MP. 
     
     
         17 . A blend composition for enhanced heat transfer fluid performance, said blend composition comprising:
 (i) at least one base heat transfer fluid, and   (ii) one or more lubricating oils comprising a Group I, Group II, Group III, Group IV, or Group V oil; wherein the at least one base heat transfer fluid undergoes one or more phase changes in a heat transfer process, wherein the heat transfer process comprises a heated zone and/or a cooled zone, wherein the one or more phase changes increase heat removal from the heated zone and/or increase heat rejection in the cooled zone, as compared to heat removal from a heated zone and/or heat rejection in a cooled zone of a heat transfer process having a base heat transfer fluid that does not undergo one or more phase changes.   
     
     
         18 . A method for conducting heat transfer in a heating and/or cooling system, said method comprising:
 (a) providing a composition comprising at least one base heat transfer fluid in the heating and/or cooling system; and   (b) conducting heat transfer between the at least one base heat transfer fluid and the heating and/or cooling system; wherein the least one base heat transfer fluid undergoes one or more phase changes in the heating and/or cooling system, wherein the one or more phase changes increase heat removal from the heating system and/or increase heat rejection in the cooling system, as compared to heat removal from a heating system and/or heat rejection in a cooling system having a base heat transfer fluid that does not undergo one or more phase changes.   
     
     
         19 . The method of  claim 18  wherein the at least one base heat transfer fluid comprises liquid crystals. 
     
     
         20 . The method of  claim 18  wherein the at least one base heat transfer fluid comprises one or more smectic or discotic liquid crystals. 
     
     
         21 . The method of  claim 19  wherein the one or more liquid crystals are represented by the formula:
   R1-(A) m -Y—(B) n —R2
 
 wherein R1 and R2 are the same or different and are a substituted or unsubstituted, alkyl group or alkoxy group having from about 2 to about 24 carbon atoms; 
 A and B are the same or different and are a cycloaliphatic group or aromatic group, provided at least one of A and B is an aromatic group; 
 Y is a covalent bond, —CH2-CH2-, —CH═CH—, —COO—, —CO—, —CSO—, —CSS—, —CS—, —O—, —S—, —SO—, —SO2-, or —CH2O—; and 
 m and n are independently 0, 1, 2 or 3. 
 
     
     
         22 . The method of  claim 19  wherein the one or more liquid crystals are represented by the formula: 
       
         
           
           
               
               
           
         
       
       or 
     
     
         23 . The method of  claim 19  wherein the one or more liquid crystals are selected from the group consisting of 4′-n-octyl-4-cyano-biphenyl, 4-(trans-4-heptylcyclohexyl)-pentylbenzene, 4-(trans-4-heptylcyclohexyl)-propylbenzene, and 4-(trans-4-propylcyclohexyl)-ethylbenzene. 
     
     
         24 . The method of  claim 19  wherein the one or more liquid crystals are represented by the formula:
   A-(R3) n    
 
       wherein A is a mono-ring or a multi-ring aromatic group, R3 is the same or different and is a substituted or unsubstituted, hydrocarbon group having from about 2 to about 24 carbon atoms, and n is a value from about 1 to about 12. 
     
     
         25 . The method of  claim 19  wherein the one or more liquid crystals are represented by the formula: 
       
         
           
           
               
               
           
         
       
     
     
         26 . The method of  claim 19  wherein the one or more liquid crystals comprise hexakis(octylthio)benzene. 
     
     
         27 . The method of  claim 18  wherein the at least one base heat transfer fluid has a freezing point of at least greater than about −50° C. as determined by ASTM D1777-17, a boiling point of greater than about 100° C. as determined by ASTM D1120-17, and a flash point of at least 50° C. as determined by ASTM D93-16a. 
     
     
         28 . The method of  claim 18  wherein the composition further comprises one or more of a corrosion inhibitor, a thermal stabilizer, a pH stabilizer or buffer, an antiscaling agent, a viscosity modifier, or a biocide. 
     
     
         29 . The method of  claim 18  wherein the composition further comprises one or more lubricating oils to form a bimodal blend, wherein the one or more lubricating oils comprise a Group I, Group II, Group III, Group IV, or Group V oil, and mixtures thereof. 
     
     
         30 . The method of  claim 18  further comprising conducting heat transfer between the at least one base heat transfer fluid and the heating and/or cooling system at a temperature and/or pressure sufficient to cause the at least one base heat transfer fluid to undergo one or more phase changes. 
     
     
         31 . The method of  claim 18  further comprising conducting heat transfer between the at least one base heat transfer fluid and the heating and/or cooling system at a temperature from about −40° C. to greater than about 80° C., and/or a pressure from about 50 MP to about 500 MP. 
     
     
         32 . A method of heat transfer comprising:
 (a) providing an object to be heated or cooled; and   (b) transferring heat to or from the object to be heated or cooled by a composition comprising at least one base heat transfer fluid, wherein the least one base heat transfer fluid undergoes one or more phase changes, wherein the one or more phase changes increase heat removal from the object and/or increase heat rejection in the object, as compared to heat removal from an object and/or heat rejection in an object by a base heat transfer fluid that does not undergo one or more phase changes.