Magneto-caloric regenerator system and method

Abstract

A regenerator having a thermal diffusivity matrix is presented. The thermal diffusivity matrix includes magneto-caloric material having multiple miniature protrusions intimately packed to form a gap between the protrusions. A fluid path is provided within the gap to facilitate flow of a heat exchange fluid and further provide efficient thermal exchange between the heat exchange fluid and magneto-caloric material. A first layer is disposed on each of the miniature protrusion to physically isolate the heat exchange fluid and magneto-caloric material, wherein the first layer further includes a soft magnetic material configured to simultaneously enhance a permeability and a thermal efficiency of the thermal diffusivity matrix.

1 . A regenerator comprising:
 a thermal diffusivity matrix of magneto-caloric material comprising a plurality of miniature protrusions intimately packed to form a gap between the protrusions;   a fluid path defined within the gap to facilitate flow of a heat exchange fluid and efficient thermal exchange between the heat exchange fluid and magneto-caloric material; and   a first layer disposed on each of the miniature protrusion to physically isolate the heat exchange fluid and magneto-caloric material, wherein the first layer further comprise a soft magnetic material configured to simultaneously enhance a permeability and a thermal efficiency of the regenerator.   
     
     
         2 . The regenerator of  claim 1 , wherein said each miniature protrusion comprise a high aspect ratio such that the height of each miniature protrusion is at least more than 10 times the cross-section area of each said miniature protrusion. 
     
     
         3 . The regenerator of  claim 1 , wherein the thermal diffusivity matrix is subjected to an external magnetic field prior to assembling the miniature protrusions to align the spin within one or more magnetic domains of the magnet-caloric material. 
     
     
         4 . The regenerator of  claim 1  further comprising a magnet assembly to magnetize and de-magnetize the regenerator cyclically. 
     
     
         5 . The regenerator of  claim 1 , wherein the miniature protrusions comprise a plurality of miniature pin structures. 
     
     
         6 . The regenerator of  claim 1 , wherein the miniature protrusions comprise a plurality of miniature plate structures. 
     
     
         7 . The regenerator of  claim 1 , wherein the miniature protrusions are arranged in a honeycomb structure. 
     
     
         8 . The regenerator of  claim 1  further coupled to a load and a sink. 
     
     
         9 . The regenerator of  claim 8 , wherein the heat exchange fluid is configured to facilitate thermal exchange between the load and the sink. 
     
     
         10 . A regenerator comprising:
 a thermally conducting material defining a plurality of micro fluidic channels adjacent to each other;   a magneto-caloric material disposed within a plurality of pockets formed between said micro fluidic channels;   a fluid path defined within said micro fluidic channels, said fluid path facilitate flow of a heat exchange fluid, wherein the magneto-caloric material and the heat exchange fluid are in thermal communication and physical isolation.   
     
     
         11 . The system of  claim 10 , wherein the magneto-caloric material comprises at least one of a granular, a powder, or a high-density structure. 
     
     
         12 . The system of  claim 10 , wherein said micro fluid channels are arranged in a fin structure. 
     
     
         13 . The system of  claim 12  further comprising multiple spiral coils disposed within the micro fluid channels. 
     
     
         14 . The system of  claim 12 , wherein the micro fluid channels comprise roughened inner surface. 
     
     
         15 . A magneto-caloric system comprising:
 a regenerator comprising:
 a magnetically aligned cluster of a magneto-caloric material, the cluster comprising miniature protrusions arranged intimately to form a gap between said miniature protrusions; and 
 a fluid path within said gap configured to exchange thermal units between a heat exchange fluid and the magneto-caloric material; 
   a magnet assembly to generate magnetic flux that magnetize and de-magnetize the regenerator cyclically;   a fluid circuit coupling a load, a sink, and the regenerator, wherein the heat exchange fluid facilitate exchange of thermal units between the load and the sink.   
     
     
         16 . The magneto-caloric regenerator of  claim 15  further comprising a first layer disposed around said each miniature protrusions. 
     
     
         17 . The magneto-caloric regenerator of  claim 16 , wherein the first layer is configured to simultaneously enhance the magnetic permeability and the thermal efficiency of the regenerator. 
     
     
         18 . The magneto-caloric regenerator of  claim 16 , wherein the first layer is configured to chemically isolate the magneto-caloric material from the fluid path. 
     
     
         19 . The magneto-caloric regenerator of  claim 15  further comprising an external magnetic field to align cluster of the magneto-caloric material 
     
     
         20 . The magneto-caloric regenerator of  claim 15 , wherein the fluid path is thermally coupled and physically isolated from the magneto-caloric material. 
     
     
         21 . A magneto-caloric system comprising:
 a regenerator made of magneto-caloric material configured to heat or cool when magnetically excited;   a magnetic assembly to generate a first magnetic field configured to excite the regenerator;   a second magnetic source to generate a high frequency magnetic field configured to excite the regenerator; and   a fluid circuit to facilitate flow of a heat exchange fluid though the regenerator configured to transfer thermal units between a load and a sink.   
     
     
         22 . The system of  claim 21 , wherein the magnetic field is configured to produce a magnetization and demagnetization cycle. 
     
     
         23 . The system of  claim 21 , wherein the high frequency magnetic field is configured to overlap the magnetic field for at least a partial interval of time. 
     
     
         24 . The system of  claim 23 , wherein high frequency magnetic field is configured re-align domain wall of the magneto-caloric material.