Nanoparticles for Heat Transfer and Thermal Energy Storage

Abstract

An article of manufacture and method of preparation thereof. The article of manufacture and method of making the article includes an eutectic salt solution suspensions and a plurality of nanocrystalline phase change material particles having a coating disposed thereon and the particles capable of undergoing the phase change which provides increase in thermal energy storage. In addition, other articles of manufacture can include a nanofluid additive comprised of nanometer-sized particles consisting of copper decorated graphene particles that provide advanced thermal conductivity to heat transfer fluids.

What is claimed is: 
     
         1 . An article of manufacture, comprising:
 a silica encapsulated tin nanoparticle comprising a tin nanoparticle having a silica encapsulating coating disposed thereabout; and   a heat transfer fluid;   wherein the silica encapsulated tin nanoparticle is dispersed in the heat transfer fluid.   
     
     
         2 . The article of manufacture of  claim 1 , further comprising a surfactant. 
     
     
         3 . The article of manufacture of  claim 2  wherein the surfactant is benzalko chloride. 
     
     
         4 . The article of manufacture of  claim 1 , wherein a percentage volume of loading of the silica encapsulated tin nanoparticle in the heat transfer fluid is within the range of 1 vol. % to 5 vol. %. 
     
     
         5 . The article of manufacture of  claim 1 , wherein the tin nanoparticle has a diameter of between 60 nm and 100nm. 
     
     
         6 . The article of manufacture of  claim 1 , wherein the silica encapsulating coating has a thickness of about 5 nm. 
     
     
         7 . The article of manufacture of  claim 1 , further comprising a polyvinylpyrrolidone layer disposed on the tin nanoparticle. 
     
     
         8 . The article of manufacture of  claim 1 , wherein the tin nanoparticle includes impurities. 
     
     
         9 . A method of making phase change nanoparticles comprising:
 synthesizing tin nanoparticles by a modified polyole wet-chemical reduction process;   encapsulating the tin nanoparticles with a silica encapsulating coating;   suspending the encapsulated tin nanoparticles in a heat transfer fluid.   
     
     
         10 . The method of  claim 9 , wherein the modified polyole wet-chemical reduction process comprises:
 heating a reaction solution containing polyvinylpyrrolidone (PVP);
 adding a SnC12 solution to the reaction solution; 
 adding a NaBH4 solution to the reaction solution, forming the tin nanoparticles; and 
 removing the tin nanoparticles from the reaction solution. 
   
     
     
         11 . The method of  claim 10 , further comprising dissolving the PVP in tetraethylene glycol and heating to about 140 C. 
     
     
         12 . The method of  claim 10 , wherein the NaBH 4  solution comprises 15 g:200 ml ratio of NaBH 4  to tetraethylene glycol. 
     
     
         13 . The method of  claim 10 , wherein the NaBH4 solution is added drop-wise. 
     
     
         14 . The method of  claim 10 , wherein the reaction solution is maintained at about 140 C during addition of SnC12 and addition of NaBH4 and for 90 minutes thereafter. 
     
     
         15 . The method of  claim 10 , wherein the reaction solution is constantly stirred under an inert atmosphere. 
     
     
         16 . The method of  claim 10 , wherein encapsulating the tin nanoparticles comprises base-catalyzed hydrolysis of tetraethyl-ortho-silicate (TEOS). 
     
     
         17 . The method of  claim 16 , wherein the base-catalyzed hydrolysis TEOS comprises:
 suspending the tin nanoparticles in ethanol;   sonifying the suspended tin particles;   increasing the suspended tin particles to a temperature of 40° C.; and   adding the TEOS to the suspended tin particles.   
     
     
         18 . The method of  claim 17 , wherein the TEOS is added dropwise and a resultant mixture is stirred in a darkened environment to prevent photo-polymerization. 
     
     
         19 . An article of manufacture, comprising:
 an encapsulated nanoparticle comprising a nanoparticle having a ceramic encapsulating coating disposed thereabout; and   a heat transfer fluid;   wherein the ceramic encapsulated nanoparticle is dispersed in the heat transfer fluid.   
     
     
         20 . The article of manufacture of  claim 19 , wherein the ceramic encapsulated nanoparticle comprises a tin nanoparticle.