High Temperature Graphite Heat Exchanger

Abstract

A graphite-based heat exchanger, especially for use as a solar energy receptor as part of the thermal process in a solar power system, including an energy collection panel, a heat spreader, and a thermal element, wherein the heat spreader is formed of flexible graphite having a density of at least about 0.6 g/cc and a thickness of less than about 10 mm, and the heat spreader further has a first side and a second side, wherein the heat spreader is in a thermal transfer relationship with the thermal element, and wherein the energy collection panel includes at least one sheet or block of graphite.

1 . A heat exchanger system, comprising:
 (a) a thermal element comprising a surface;   (b) a heat spreader comprising at least one sheet of compressed particles of exfoliated graphite having a density of at least about 0.6 g/cc and a thickness of less than about 10 mm, and further comprising a first surface and a second surface, wherein the heat spreader is positioned relative to the thermal element so that the heat spreader is at least partially wrapped around the thermal element such that the heat spreader is in a thermal transfer relationship with a portion of the thermal element surface; and   (c) a substrate comprising graphite, wherein the substrate is positioned relative to the heat spreader so that the substrate is in a thermal transfer relationship with the heat spreader.   
     
     
         2 . The heat exchanger system of  claim 1 , wherein the substrate comprises a recess dimensioned to accommodate the thermal element, wherein the substrate is disposed adjacent to the heat spreader, such that the heat spreader is positioned between the thermal element and the substrate, and wherein the substrate has a thermal conductivity of greater than about 150 W/m-K. 
     
     
         3 . The heat exchanger system of  claim 1 , wherein the heat spreader comprises two components, a first component and a second component, further wherein the first component of the heat spreader is positioned between the thermal element and the substrate. 
     
     
         4 . The heat exchanger system of  claim 1 , which further comprises an energy collection panel. 
     
     
         5 . The heat exchanger of  claim 2 , wherein the heat spreader comprises two components, a first component and a second component, further wherein the second component of the heat spreader extends across the recess such that the second component of the heat spreader is positioned between the thermal element and an energy collection panel. 
     
     
         6 . The heat exchanger system of  claim 1 , wherein the at least one sheet of compressed particles of exfoliated graphite has a density of at least about 1.1 g/cc. 
     
     
         7 . The heat exchanger system of  claim 1 , wherein the heat spreader comprises two components, a first component and a second component, further wherein the first component of the heat spreader cooperates with the substrate to form a substrate spreader recess. 
     
     
         8 . The heat exchanger system of  claim 1 , further comprising a structural element comprising a surface that is in thermal transfer relationship with a portion of the thermal element surface and wherein the structural element comprises at least one layer of synthetic graphite. 
     
     
         9 . The heat exchanger system of  claim 1 , wherein the substrate comprises at least one layer of synthetic graphite. 
     
     
         10 . The heat exchanger system of  claim 1  further comprising a protective layer having a first surface and a second surface wherein the first surface of the protective layer is located between an energy source and the thermal element. 
     
     
         11 . The heat exchanger system of  claim 1 , which comprises a solar energy receptor. 
     
     
         12 . A heat exchanger system comprising:
 (a) a first layer of graphite having a first surface and a second surface;   (b) a second layer of graphite positioned below the second surface of the first layer of graphite;   (c) a thermal element positioned between the first layer of graphite and the second layer of graphite;   (d) a heat spreader comprising at least one sheet of compressed particles of exfoliated graphite having a density of at least about 0.6 g/cc and an in-plane thermal conductivity of at least about 140 W/m-K, wherein the heat spreader is positioned in thermal transfer relationship with the first layer of graphite, the second layer of graphite, and the thermal element.   
     
     
         13 . The heat exchanger system of  claim 12 , wherein the at least one sheet of compressed particles of exfoliated graphite has an in-plane thermal conductivity of at least about 220 W/m-K. 
     
     
         14 . The heat exchanger system of  claim 12  wherein the first layer of graphite has an in-plane thermal conductivity of at least about 120 W/m-K. 
     
     
         15 . The heat exchanger system of  claim 12 , which comprises a solar energy receptor. 
     
     
         16 . A heat exchanger system, comprising:
 (a) at least one layer of graphite;   (b) at least one thermal passageway for containing heat transfer fluid therein, wherein the passageway traverses the at least one layer of graphite;   (c) a heat spreader comprising at least one sheet of compressed particles of exfoliated graphite having a density of at least about 0.6 g/cc and an in-plane thermal conductivity of at least about 140 W/m-K, wherein the heat spreader is positioned in thermal transfer relationship with both the at least one layer of graphite and the thermal passageway.   
     
     
         17 . The heat exchanger system of  claim 16 , wherein the at least one sheet of compressed particles of exfoliated graphite has an in-plane thermal conductivity of at least about 220 W/m-K. 
     
     
         18 . The heat exchanger system of  claim 16 , wherein the at least one layer of graphite has an in-plane thermal conductivity of at least about 120 W/m-K. 
     
     
         19 . The heat exchanger system of  claim 16 , which comprises a solar energy receptor. 
     
     
         20 . The heat exchanger system of  claim 16 , further comprising a protective layer having a first surface and a second surface wherein the first surface of the protective layer is located between an energy source and the thermal element.