Stacked graphite heat exchanger

Abstract

The present invention provides heat exchanger systems, and associated methods, using thermally anisotropic carbon sheets or carbon fiber materials, preferably pyrolytic graphite sheets or woven graphite fiber sheets, where heat is transferred from a high temperature source at one end of the heat exchanger to a lower temperature source or heat sink at the other end of the heat exchanger.

We claim: 
     
         1 . A heat exchanger comprising:
 a) a plurality of carbon sheets, each of the plurality of carbon sheets having a first end and a second, wherein the plurality of carbon sheets are thermally anisotropic in the direction extending from the first end to the second end, and   b) a support structure comprising one or more holding regions, wherein the plurality of carbon sheets are connected to the support structure at the one or more holding regions,   wherein the plurality of carbon sheets comprises 2 or more carbon sheets stacked on each other.   
     
     
         2 . The heat exchanger of  claim 1 , wherein the plurality of carbon sheets comprises between 10 and 100 carbon sheets. 
     
     
         3 . The heat exchanger of  claim 1 , wherein the plurality of carbon sheets comprises between 20 and 100 carbon sheets. 
     
     
         4 . The heat exchanger of  claim 1 , wherein the plurality of carbon sheets comprises between 20 and 60 carbon sheets. 
     
     
         5 . The heat exchanger of  claim 1 , wherein the carbon sheets are pyrolytic graphite sheets. 
     
     
         6 . The heat exchanger of  claim 1 , wherein each of the carbon sheets have a thickness between about 20 μm to 200 μm. 
     
     
         7 . The heat exchanger of  claim 1 , wherein each of the carbon sheets have a thickness between about 45 μm to 80 μm. 
     
     
         8 . The heat exchanger of  claim 1 , wherein the support structure comprises a first holding region and a second holding region,
 wherein the first holding region comprises a first pressure plate, wherein the first ends of the plurality of carbon sheets are inserted through and held in place by the first pressure plate,   wherein the second holding region comprises a second pressure plate, wherein the second ends of the plurality of carbon sheets are inserted through and held in place by the second pressure plate.   
     
     
         9 . The heat exchanger of  claim 8 , wherein the first and second ends of the plurality of carbon sheets are held in place by the first and second pressure plates using pressure plate screws and an epoxy. 
     
     
         10 . The heat exchanger of  claim 9 , wherein the epoxy is silver epoxy. 
     
     
         11 . The heat exchanger of  claim 8 , wherein the first ends of the plurality of carbon sheets, the second ends of the plurality of carbon sheets, or both the first and second ends of the plurality of carbon sheets extend all of the way through the pressure plates. 
     
     
         12 . The heat exchanger of  claim 8 , wherein the first ends of the plurality of carbon sheets, the second ends of the plurality of carbon sheets, or both the first and second ends of the plurality of carbon sheets only extend through a portion of the pressure plates. 
     
     
         13 . The heat exchanger of  claim 8  further comprising a high temperature heat source in thermal communication with the first ends of the plurality of carbon sheets. 
     
     
         14 . The heat exchanger of  claim 8  further comprising a lower temperature heat source in thermal communication with the second ends of the plurality of carbon sheets. 
     
     
         15 . The heat exchanger of  claim 1  further comprising a layer of polyethylene terephthalate (PET) on at least one side of each of the plurality of carbon sheets. 
     
     
         16 . The heat exchanger of  claim 15 , wherein each of the plurality of carbon sheets has a PET layer on one side, wherein the opposing side is untreated with PET, and the plurality of carbon sheets are stacked in two or more alternating pairs, so that
 sides of carbon sheets having the PET layer in a first pair are in contact with each other, and untreated sides of carbon sheets in a second pair are in contact with each other.   
     
     
         17 . A method for transferring heat comprising the steps of:
 a) providing a heat exchanger, said heat exchanger comprising:
 i) a plurality of carbon sheets, each of the plurality of carbon sheets having a first end and a second end, wherein the plurality of carbon sheets are thermally anisotropic in the direction extending from the first end to the second end; and 
 ii) a support structure comprising one or more holding regions, wherein the plurality of carbon sheets are connected to the support structure at the one or more holding regions; 
   b) positioning the first ends of the one or more carbon sheets to be in thermal communication with a high temperature heat source, and the second ends of the one or more carbon sheets to be in thermal communication with a lower temperature source;   c) transferring heat between the high temperature heat source and the lower temperature source,   wherein the plurality of carbon sheets comprises 2 or more carbon sheets stacked on each other.   
     
     
         18 . The method of  claim 17 , wherein the plurality of carbon sheets comprises between 20 and 100 carbon sheets, wherein the carbon sheets are pyrolytic graphite sheets. 
     
     
         19 . The method of  claim 17 , wherein each of the carbon sheets have a thickness between about 45 μm to 80 μm. 
     
     
         20 . The method of  claim 17 , wherein the support structure comprises a first holding region and a second holding region,
 wherein the first holding region comprises a first pressure plate, wherein the first ends of the plurality of carbon sheets are inserted through and held in place by the first pressure plate,   wherein the second holding region comprises a second pressure plate, wherein the second ends of the plurality of carbon sheets are inserted through and held in place by the second pressure plate.