Working fluid and manufacturing method of metal particles

Abstract

A working fluid in cooperation with a solar thermal system comprises a heat conduction medium and a plurality of metal particles mixed in the heat conduction medium. Each of the metal particles includes a metal particle and a protection layer, and the protection layer is an oxide and covers the metal particle. A manufacturing method of metal particles is also disclosed.

What is claimed is: 
     
         1 . A working fluid, comprising:
 a heat conduction medium; and   a plurality of metal particles mixed in the heat conduction medium, wherein each of the metal particles includes an alloy particle and a protection layer covering the alloy particle, the alloy particle includes a first metal and a second metal, and the effective heat capacity of the working fluid is dependent on an expected ratio of the first metal to the second metal.   
     
     
         2 . The working fluid as recited in  claim 1 , wherein the temperature range of the latent heat absorption/releasing is dependent on the expected ratio of the first metal to the second metal. 
     
     
         3 . The working fluid as recited in  claim 1 , wherein the weight percent of the metal particles added to the heat conduction medium ranges between 1% and 20%. 
     
     
         4 . The working fluid as recited in  claim 1 , wherein the expected ratio of the first metal to the second metal is controllable. 
     
     
         5 . The working fluid as recited in  claim 1 , wherein the melting point of the protection layer is higher than the melting points of the first metal and the second metal. 
     
     
         6 . The working fluid as recited in  claim 1 , wherein the material of the protection layer comprises oxide. 
     
     
         7 . The working fluid as recited in  claim 6 , wherein the oxide comprises metal oxide or silicon oxide. 
     
     
         8 . The working fluid as recited in  claim 1 , wherein the first metal is Zn and the second metal is Sn.