Devices for heat transfer

Abstract

Devices and methods of heat transfer are provided. In an example, a thermo-reversible hydrogel is provided in a first portion of a casing of a device. A wicking surface is provided in an inner surface of the casing between the first portion and the second portion.

We claim: 
     
         1 . A device for heat transfer comprising:
 a casing, wherein the casing comprises:
 a first portion to receive heat from a heat source; 
 a thermo-reversible hydrogel provided in the first portion; and 
 a wicking surface provided along an inner surface of the casing and connecting the first portion to a second portion of the casing. 
   
     
     
         2 . The device of  claim 1 , wherein the device is one of a heat pipe and a vapor chamber. 
     
     
         3 . The device of  claim 1 , wherein the thermo-reversible hydrogel is selected from ethylene maleic anhydride copolymer, carboxymethyl cellulose, polyvinyl alcohol copolymers, starch grafted copolymer of polyacrylonitrile or polyacrylamide super absorbents, and combinations thereof. 
     
     
         4 . The device of  claim 1 , wherein the wicking surface is one of a sintered metal powder, a screen, and a grooved wicking surface. 
     
     
         5 . The device of  claim 1 , wherein a thickness of the thermo-reversible hydrogel is in a range of 100-800 μm. 
     
     
         6 . The device of  claim 1 , wherein the first portion comprises a working fluid and wherein the thermo-reversible hydrogel is soaked in the working fluid. 
     
     
         7 . The device of  claim 6 , wherein the casing and the wicking surface are fabricated from copper and wherein the working fluid is water. 
     
     
         8 . A method of preparing a device for heat transfer, the method comprising:
 sintering a wick material powder along an inner surface of a casing of the heat transfer device;   coating a thermo-reversible hydrogel on an inner surface of a first portion of the casing of the heat transfer device; and   drying the thermo-reversible hydrogel.   
     
     
         9 . The method of  claim 8 , wherein coating the thermo-reversible hydrogel comprises spraying a solution comprising the thermo-reversible hydrogel on the inner surface at a pressure in a range of about 0.0005-0.002 Torr, wherein the solution comprises the thermo-reversible hydrogel in a range of about 0.1-3.0% weight by volume of the solution. 
     
     
         10 . The method of  claim 8 , wherein sintering is performed at about 700-1300° C. for about 30-60 minutes. 
     
     
         11 . The method of  claim 8 , wherein drying of the thermo-reversible hydrogel is performed at a temperature of about 105-120° C. for about 15-40 minutes. 
     
     
         12 . The method of  claim 8 , wherein the method further comprises injecting a working fluid into the first portion of the casing under vacuum. 
     
     
         13 . A device comprising:
 a first portion comprising a thermo-reversible hydrogel soaked in a working fluid;   a second portion substantially opposite to the first portion;   a vapor region between the first portion and the second portion; and   a wicking surface enclosing the vapor region, wherein the vapor region and the wicking surface fluidly couple the first portion and the second portion for heat transfer between the first portion and the second portion.   
     
     
         14 . The device as claimed in  claim 13 , wherein, when a first temperature of the first portion is higher than a second temperature of the second portion:
 the vapor region is to transfer vapors of the working fluid from the first portion to the second portion for condensation;   the wicking surface is to transfer condensed working fluid from the second portion to the first portion; and   the thermo-reversible hydrogel is to absorb the condensed working fluid.   
     
     
         15 . The device as claimed in  claim 13 , wherein, when a second temperature of the second portion is higher than a first temperature of the first portion:
 the vapor region is to transfer vapors of the working fluid from the second portion to the first portion for condensation;   the wicking surface is to transfer condensed working fluid from the first portion to the second portion; and   the thermos-reversible hydrogel is to absorb the vapors.