Fiber member and heat exchanger including fiber member

Abstract

A fiber member is made of mutually entwined fibers, a surface of each of the fibers is coated with a material having a thermal conductivity higher than the fibers, and a porosity Pr (Pr=Vp/Vm×100) is 60% or more, where an apparent volume of the fiber member is Vm, and a void volume of the fiber member is Vp.

What is claimed is: 
     
         1 . A fiber member made of mutually entwined fibers,
 wherein a surface of each of the fibers is coated with a material having a thermal conductivity higher than the fibers, and   wherein a porosity Pr (Pr=Vp/Vm×100) is 60% or more, where an apparent volume of the fiber member is Vm, and a void volume of the fiber member is Vp.   
     
     
         2 . The fiber member according to  claim 1 , wherein the material coating the surface of each of the fibers comprises at least one of Al, Cu, Ag, Au, and HfO 2 . 
     
     
         3 . The fiber member according to  claim 1 , wherein the material coating the surface of each of the fibers comprises carbon atoms of 1 at % or more and 25 at % or less. 
     
     
         4 . The fiber member according to  claim 1 , wherein an average diameter of the fibers of the fiber member is 1,000 nm or less. 
     
     
         5 . The fiber member according to  claim 1 , wherein the fibers comprise a carbon fiber, a glass fiber, a resin fiber and/or a natural fiber. 
     
     
         6 . A heat-transfer tube unit comprising:
 a heat-transfer tube; and   the fiber member according to  claim 1  inside the heat-transfer tube,
 wherein a heat exchange is performed by flowing a refrigerant in the heat-transfer tube. 
   
     
     
         7 . The heat-transfer tube unit according to  claim 6 , wherein a thickness of the fiber member is 1 mm or more in a direction in which the refrigerant in the heat-transfer tube flows. 
     
     
         8 . The heat-transfer tube unit according to  claim 6 , wherein an inner wall of the heat-transfer tube is in contact with the fiber member. 
     
     
         9 . The heat-transfer tube unit according to  claim 6 , wherein an inner wall of the heat-transfer tube is coated with a same material as the material coating the surface of each of the fibers. 
     
     
         10 . The heat-transfer tube unit according to  claim 6 , comprising heat exchange fins welded to an outer surface of the heat-transfer tube. 
     
     
         11 . The heat-transfer tube unit according to  claim 6 , wherein the heat-transfer tube is made of copper or aluminum. 
     
     
         12 . A heat exchanger comprising:
 the heat-transfer tube unit according to  claim 6 ; and   a refrigerant in the heat-transfer tube.   
     
     
         13 . A production method of producing a fiber member to be arranged inside a heat-transfer tube for performing a heat exchange by flowing a refrigerant through the heat-transfer tube, the production method comprising:
 preparing fibers;   coating surfaces of fibers with a material having a thermal conductivity higher than the fibers; and   entwining the fibers together.   
     
     
         14 . The production method according to  claim 13 , wherein the coating is performed after the entwining. 
     
     
         15 . The production method according to  claim 13 , wherein the coating is performed before the entwining. 
     
     
         16 . The production method according to  claim 13 , wherein the coating is performed using an atomic layer deposition method. 
     
     
         17 . The production method according to  claim 13 , wherein the coating is performed inside the heat-transfer tube. 
     
     
         18 . The production method according to  claim 13 , wherein the coating includes coating an inner wall of the heat-transfer tube with a material same as the material coating the surfaces of fibers. 
     
     
         19 . The production method according to  claim 13 , wherein the fibers comprise a carbon fiber, a glass fiber, a resin fiber and/or a natural fiber. 
     
     
         20 . The production method according to  claim 13 , wherein the material coating the surface of each of the fibers comprises at least one of Al, Cu, Ag, Au, and HfO 2 .