Plate-Frame Graphite-Foam Heat Exchanger

Abstract

A heat exchanger for thermally coupling a first fluid and second fluid is disclosed. The heat exchanger comprises plates comprising cores of thermally conductive graphite foam. A plurality of conduits for conveying the first fluid is formed in each core. Each plate further comprises thermally conductive barriers that sandwich the core, wherein the barriers are substantially impervious to r the first fluid and second fluid. Plates are stacked in a frame such that the frame and plates collectively define a plurality of channels for conveying the second fluid. Heat is exchanged between the primary fluid and the secondary fluid through the graphite-foam cores and barriers. Heat exchangers in accordance with the present invention can be lighter, have improved ratio of heat transfer surface density to heat exchanger volume, be lower cost, and/or be smaller for a given heat transfer capability than prior-art heat exchangers.

1 . A heat exchanger for thermally coupling a first fluid and a second fluid, wherein the heat exchanger comprises:
 a first frame, wherein the first frame comprises;
 a first core, wherein the first core comprises graphite foam comprising first conduits for conveying the first fluid; and 
 a first barrier for fluidically isolating the first fluid and the second fluid; and 
   a second frame, wherein the second frame comprises;
 a second core, wherein the second core comprises graphite foam comprising second conduits for conveying the first fluid; and 
 a second barrier for fluidically isolating the first fluid and the second fluid; 
   wherein the first frame and the second frame collectively define a channel for conveying the second fluid.   
     
     
         2 . The heat exchanger of  claim 1  wherein the second barrier comprises a plate, and wherein the plate is mechanically rigid, and wherein the plate is substantially impervious for each of the first fluid and the second fluid. 
     
     
         3 . The heat exchanger of  claim 1  wherein the first barrier comprises a metal. 
     
     
         4 . The heat exchanger of  claim 3  wherein the metal comprises aluminum. 
     
     
         5 . The heat exchanger of  claim 1  further comprising:
 a frame, wherein the frame consists of a first metal;   wherein the second barrier consists of the first metal; and   wherein the second barrier consists of the first metal;   wherein the frame, first barrier, and second barrier are joined with substantially galvanic corrosion-free joints.   
     
     
         6 . The heat exchanger of  claim 5  wherein the galvanic corrosion-free joints are friction-stir welding joints. 
     
     
         7 . The heat exchanger of  claim 1  wherein the first barrier comprises a polymer that is substantially impervious to each of the first fluid and the second fluid. 
     
     
         8 . The heat exchanger of  claim 7  wherein the polymer is a thermally enhanced polymer. 
     
     
         9 . The heat exchanger of  claim 1  wherein the first core consists substantially of graphite foam. 
     
     
         10 . The heat exchanger of  claim 1  wherein the first core consists of graphite foam. 
     
     
         11 . The heat exchanger of  claim 1  wherein each of the first conduits further comprises second conduits, and wherein the second conduits and the first conduits are fluidically coupled. 
     
     
         12 . A heat exchanger for thermally coupling a first fluid and a second fluid, wherein the heat exchanger comprises:
 (1) a plurality of plates, wherein each of the first plates comprises;
 (a) a core, wherein the core comprises a plurality of conduits for conveying the first fluid, and further wherein the core comprises graphite foam; 
 (b) a first barrier, wherein the first barrier is substantially impervious to the first fluid and the second fluid; and 
 (c) a second barrier, wherein the second barrier is substantially impervious to the first fluid and the second fluid; 
 wherein the first barrier is physically coupled with a first surface of the core; 
 wherein the second barrier is physically coupled with a second surface of the core that is opposite the first surface of the core; and 
 wherein the first barrier and second barrier are substantially thermally conductive; and 
   (2) a frame for locating each of the plurality of plates, wherein the frame locates the plurality of plates such that the frame and the plurality of plates collectively define a plurality of channels for conveying the second fluid.   
     
     
         13 . The heat exchanger of  claim 12  wherein each of the frame, the first barrier, and the second barrier comprises a first metal, and wherein the frame and each of the first barriers and second barriers are joined with friction-stir welding joints. 
     
     
         14 . The heat exchanger of  claim 13  wherein each of the first barrier and second barrier comprises a polymer. 
     
     
         15 . The heat exchanger of  claim 14  wherein the polymer is a thermally enhanced polymer. 
     
     
         16 . A method for forming a heat exchanger for thermally coupling a first fluid and a second fluid, wherein the method comprises:
 providing a plurality of plates, wherein each of the plurality of plates comprises a graphite-foam core and a barrier that is substantially impervious to the first fluid and the second fluid, wherein each of the graphite-foam cores comprises a plurality of conduits for conveying the first fluid;   providing a frame for locating the plurality of plates; and   mounting the plurality of plates in the frame;   wherein the frame and the plurality of plates collectively define a plurality of channels for conveying the second fluid.   
     
     
         17 . The method of  claim 16  further comprising fluidically coupling a manifold and the plurality of conduits. 
     
     
         18 . The method of  claim 16  further comprising joining the plurality of plates and the frame, wherein the plurality of plates and the frame are joined with friction-stir welding joints. 
     
     
         19 . The method of  claim 16  wherein at least one of the plurality of barriers is formed by operations comprising:
 locating a first core in a mold of an injection molding system, wherein the first core is the core of one of the plurality of plates;   injecting a polymer into the mold; and   curing the polymer.   
     
     
         20 . The method of  claim 19  further comprising providing the polymer as a thermally enhanced polymer. 
     
     
         21 . The method of  claim 16  wherein at least one of the plurality of barriers is formed by operations comprising:
 bonding a first plate to a first surface of a first core, wherein the first core is the core of one of the plurality of plates; and   bonding a second plate to a second surface of the first core;   wherein each of the first plate and the second plate is substantially impervious for the first fluid and the second fluid.   
     
     
         22 . The method of  claim 21  wherein the first plate is bonded to the first surface by means of an adhesive. 
     
     
         23 . The method of  claim 21  wherein the first plate is bonded to the first surface by operations comprising:
 disposing a first layer on the first surface, wherein the first layer comprises a first metal; and   joining the first plate and the first layer.   
     
     
         24 . The method of  claim 23  wherein the first plate and first layer are joined with a brazed joint. 
     
     
         25 . The method of  claim 23  wherein the first plate and first layer are joined with a welding joint.