Cooling device including an electrocaloric composite

Abstract

Cooling devices, heat pumps, and climate controlling devices employing an electrocaloric composite of high thermal conductivity and significant electrocaloric effect are disclosed. The electrocaloric composites include a combination of one or more EC-fluoropolymers and their blends with one or more electric-insulating fillers of high thermal conductivity.

What is claimed is: 
     
         1 . A cooling device comprising a high thermal conductivity electrocaloric (EC) composite as the refrigerant, wherein the high thermal conductivity electrocaloric composite can cycle through a temperature increase and decrease. 
     
     
         2 . The device of  claim 1 , wherein the high thermal conductivity EC composite has a thermal conductivity, along one direction, higher than 0.5 W/mK in the temperature range from 0° C. to 50° C. 
     
     
         3 . The device of  claim 1 , wherein the high thermal conductivity EC composite has a thermal conductivity, along one direction, higher than 1 W/mK in the temperature range from 0° C. to 50° C. 
     
     
         4 . The device of  claim 1 , wherein the high thermal conductivity EC composite has a thermal conductivity, along one direction, higher than 1 W/mK in the temperature range from −20° C. to 70° C. 
     
     
         5 . The device of  claim 1 , wherein the high thermal conductivity EC composite comprises one or more EC fluoropolymers having a significant electrocaloric effect in combination with one or more fillers, wherein the one or more fillers are electrically insulating and have high thermal conductivity. 
     
     
         6 . The device of  claim 5 , wherein the one or more EC fluoropolymers include a fluoropolymer made from vinylidene fluoride (VDF) based polymers which contain at least one additional fluoro-monomer including trifluoroethylene (TrFE), chlorofluoroethylene (CFE), chlorodifluoroethylene (CDFE), chlorotrifluoroethylene (CTFE), tetrafluoroethylene (TFE), hexafluoropropylene (HFP), hexafluoroethylene (HFE), vinylidene chloride (VDC), vinyl fluoride (VF) or mixture thereof. 
     
     
         7 . The device of  claim 5 , wherein the high thermal conductivity EC composite includes a blend of EC fluoropolymers. 
     
     
         8 . The device of  claim 7 , wherein the blend of EC fluoropolymers is a blend of a fluoropolymer that is a terpolymer with a fluoropolymer that is a copolymer. 
     
     
         9 . The device of  claim 5 , wherein the filler includes one or more of inorganic or organic high thermal conductivity fillers of oxides, nitrides, silicon carbide, certain carbons, polyethylene highly oriented fibers (PE) or mixtures thereof. 
     
     
         10 . The device of  claim 5 , wherein the filler volume fraction in the high thermal conductivity EC composite is less than 10 volume percent but higher than 0.1 volume percent. 
     
     
         11 . The device of  claim 5 , wherein the one or more fillers have thermal conductivity higher than 30 W/mK. 
     
     
         12 . The device of  claim 5 , wherein the one or more fillers are in a shape of nano-tube, nano-fiber, or nano-sheet. 
     
     
         13 . The device of  claim 5 , wherein the high thermal conductivity EC composite has a thermal conductivity, along one direction, higher than 0.5 W/mK in the temperature range from 0° C. to 50° C. 
     
     
         14 . The device of  claim 5 , wherein the high thermal conductivity EC composite has a thermal conductivity, along one direction, higher than 1 W/mK in the temperature range from 0° C. to 50° C. 
     
     
         15 . The device of  claim 5 , wherein the high thermal conductivity EC composite has a thermal conductivity, along one direction, higher than 1 W/mK in the temperature range from −20° C. to 70° C. 
     
     
         16 . The device of  claim 5 , wherein the one or more fillers are in the shape of a fiber of diameter larger than 1 micron and aligned which enhance the thermal conductivity of the composite along the fiber length direction while do not affect the thermal conductivity of the composite in the direction perpendicular to the aligned filler fibers. 
     
     
         17 . The device of  claim 16 , wherein the high thermal conductivity EC composite has a thermal conductivity, along one direction, higher than 1 W/mK in the temperature range from 0° C. to 50° C. 
     
     
         18 . The device of  claim 16 , wherein the high thermal conductivity EC composite has a thermal conductivity, along one direction, larger than 2 W/mK in the temperature range from −10° C. to 60° C. 
     
     
         19 . The device of  claim 16 , wherein the high thermal conductivity EC composite has a thermal conductivity, along one direction, larger than 4 W/mK in the temperature range from −20° C. to 70° C. 
     
     
         20 . The device of  claim 1 , wherein the high thermal conductivity EC composite has an electric field induce temperature change of more than 5° C. and an isothermal entropy change of larger than 22 Jkg −1 K −1  under an electric field not higher than 100 MV/m. 
     
     
         21 . The device of  claim 1 , wherein the high thermal conductivity EC composite has an electric field induce temperature changes, in the adiabatic condition, of more than 5° C. and an isothermal entropy change of larger than 22 Jkg −1 K −1  in the temperature range from 0° C. to 50° C., under an electric field not higher than 100 MV/m. 
     
     
         22 . The device of  claim 1 , wherein the high thermal conductivity EC composite has an electric field induce temperature changes, in the adiabatic condition, of more than 5° C. and an isothermal entropy change of larger than 22 Jkg −1 K −1  in the temperature range from −10° C. to 60° C., under an electric field not higher than 100 MV/m. 
     
     
         23 . The device of  claim 1 , wherein the high thermal conductivity EC composite has a dielectric breakdown field higher than 200 MV/m. 
     
     
         24 . The device of  claim 1 , wherein the high thermal conductivity EC composite comprises one or more EC fluoropolymers and one or more EC ceramics and one or more high thermal conductivity fillers.