Thermo-magnetic exchanging device

Abstract

A thermo-magnetic exchanging device includes a heat exchanging element and a magnet unit. The heat exchanging element has at least one channel to convey a heat-carrying fluid. The magnet unit is disposed around the heat exchanging element and provides a magnetic field to the heat exchanging element. The magnitude of the magnetic field is non-uniform. The cross-sectional area of the channel corresponds to the magnetic field so that temperature gradients at different points of the heat exchanging element are substantially the same when the heat-carrying fluid flows through the channel.

What is claimed is: 
     
         1 . A thermo-magnetic exchanging device, comprising:
 a heat exchanging element, having at least one channel to convey a heat-carrying fluid and having two ends; and   a magnet unit, disposed around the heat exchanging element and providing a magnetic field to the heat exchanging element, wherein the magnitude of the magnetic field is non-uniform,   wherein the cross-sectional area of the channel corresponds to the magnetic field so that temperature gradients at different points of each end of the heat exchanging element are substantially the same when the heat-carrying fluid flows through the channel.   
     
     
         2 . The thermo-magnetic exchanging device as claimed in  claim 1 , wherein the heat exchanging element is made of a material selected from a group consisting of at least one magnetocaloric material. 
     
     
         3 . The thermo-magnetic exchanging device as claimed in  claim 2 , wherein the magnetocaloric material is Me—Fe—P—As alloy, Me—Fe—P—Si alloy, Me—Fe—P—Ge alloy, Mn—As—Sb alloy, Me—Fe—Co—Ge alloy, Mn—Ge—Sb alloy, Mn—Ge—Si alloy, La—Fe—Co—Si alloy, La—Fe—Si—H alloy, La—Na—Mn—O alloy, La—K—Mn—O alloy, La—Ca—Sr—Mn—O alloy, La—Ca—Pb—Mn—O alloy, La—Ca—Ba—Mn—O alloy, Gd alloy, Gd—Si—Ge, Gd—Yb alloy, Gd—Si—Sb alloy, Gd—Dy—Al—Co alloy, or Ni—Mn—Ga alloy. 
     
     
         4 . The thermo-magnetic exchanging device as claimed in  claim 1 , wherein the magnet unit is a permanent magnet, a superconducting magnet, or a solenoid. 
     
     
         5 . A thereto-magnetic exchanging device, comprising:
 a heat exchanging element having a first channel and a second channel to convey a heat-carrying fluid, wherein the first channel has a first cross-sectional area and the second channel has a second cross-sectional area, and the first cross-sectional area is greater than the second cross-sectional area; and   a magnet unit, disposed around the heat exchanging element, providing a magnetic field to the heat exchanging element,   wherein the magnitude of the magnetic field applied to the first channel is greater than the magnitude of the magnetic field applied to the second channel.   
     
     
         6 . The thermo-magnetic exchanging device as claimed in  claim 5 , wherein the heat exchanging element is made of a material selected from a group consisting of at least one magnetocaloric material. 
     
     
         7 . The thermo-magnetic exchanging device as claimed in  claim 6 , wherein the magnetocaloric material is Me—Fe—P—As alloy, Me—Fe—P—Si alloy, Me—Fe—P—Ge alloy, Mn—As—Sb alloy, Me—Fe—Co—Ge alloy, Mn—Ge—Sb alloy, Mn—Ge—Si alloy, La—Fe—Co—Si alloy, La—Fe—Si—H alloy, La—Na—Mn—O alloy, La—K—Mn—O alloy, La—Ca—Sr—Mn—O alloy, La—Ca—Pb—Mn—O alloy, La—Ca—Ba—Mn—O alloy, Gd alloy, Gd—Si—Ge, Gd—Yb alloy, Gd—Si—Sb alloy, Gd—Dy—Al—Co alloy, or Ni—Mn—Ga alloy. 
     
     
         8 . The thermo-magnetic exchanging device as claimed in  claim 5 , wherein the magnet unit is a permanent magnet, a superconducting magnet, or a solenoid. 
     
     
         9 . A thermo-magnetic exchanging device, comprising:
 a heat exchanging element having a plurality of first channels and at least one second channel to convey a heat-carrying fluid, wherein the distance between the two adjacent first channels is greater than the distance between the two adjacent first channel and second channel; and   a magnet unit, disposed around the heat exchanging element, providing a magnetic field applied to the heat exchanging element,   wherein the magnitude of the magnetic field applied to each of the first channels is greater than the magnitude of the magnetic field applied to the second channel.   
     
     
         10 . The thermo-magnetic exchanging device as claimed in  claim 9 , wherein the heat exchanging element is made of a material selected from a group consisting of at least one magnetocaloric material. 
     
     
         11 . The thermo-magnetic exchanging device as claimed in  claim 10 , wherein the magnetocaloric material is Me—Fe—P—As alloy, Me—Fe—P—Si alloy, Me—Fe—P—Ge alloy, Mn—As—Sb alloy, Me—Fe—Co—Ge alloy, Mn—Ge—Sb alloy, Mn—Ge—Si alloy, La—Fe—Co—Si alloy, La—Fe—Si—H alloy, La—Na—Mn—O alloy, La—K—Mn—O alloy, La—Ca—Sr—Mn—O alloy, La—Ca—Pb—Mn—O alloy, La—Ca—Ba—Mn—O alloy, Gd alloy, Gd—Si—Ge, Gd—Yb alloy, Gd—Si—Sb alloy, Gd—Dy—Al—Co alloy, or Ni—Mn—Ga alloy. 
     
     
         12 . The thermo-magnetic exchanging device as claimed in  claim 9 , wherein the magnet unit is a permanent magnet, a superconducting magnet, or a solenoid.