Multiple Thermal Circuit Heat Spreader

Abstract

A heat spreader has more than one thermal circuit to give better performance over a wider range of heat input regimes. Different working fluids may be used in the different thermal circuits. The thermal circuits may extend in three dimensions to improve the density of the channels in limited space.

What is claimed is: 
     
         1 . A heat spreading device for transferring heat from a heat source to a heat sink, the heat spreader device comprising:
 a first conduit extending in a loop and having a length between the heat source and the heat sink;   a second conduit proximate the first conduit and in thermal communication with the first conduit over at least some of the length of the first conduit.   
     
     
         2 . A heat spreading device as set forth in  claim 1  wherein the second conduit is in thermal communication with the first conduit over substantially the entire length of the first conduit. 
     
     
         3 . A heat spreading device as set forth in  claim 1  wherein the second conduit conforms to the first conduit over the entire length of the first conduit. 
     
     
         4 . A heat spreading device as set forth in  claim 1  wherein the second conduit is in thermal communication with the first conduit over a portion of the first conduit near only one of either the heat source or the heat sink. 
     
     
         5 . A heat spreading device as set forth in  claim 1  further comprising a working fluid in the first and second conduit. 
     
     
         6 . A heat spreading device as set forth in  claim 5  wherein at least one of the working fluid in the first conduit and the working fluid in the second conduit includes nanoparticles. 
     
     
         7 . A heat spreading device as set forth in  claim 5  wherein the working fluid in the first conduit is different from the working fluid in the second conduit. 
     
     
         8 . A heat spreading device as set forth in  claim 1  wherein the first and second conduits are each formed at least in part out of a single piece of material. 
     
     
         9 . A heat spreading device as set forth in  claim 1  comprising a first plate and a second plate, portions of the first and second conduits being defined in the material of the first plate, and portions of the first and second conduits being defined in the material of the second plate. 
     
     
         10 . A heat spreading device as set forth in  claim 1  wherein the first and second conduits follow tortuous paths. 
     
     
         11 . A heat spreading device as set forth in  claim 9  wherein the first and second conduits each include segments extending in three different dimensions. 
     
     
         12 . A heat spreading device as set forth in  claim 1  wherein an internal surface of at least a portion of one of the first or second conduits is treated to optimize heat transfer. 
     
     
         13 . A heat spreading device as set forth in  claim 1  wherein the device is adapted to receive heat from at least two spaced apart heat sources. 
     
     
         14 . A heat spreading device as set forth in  claim 13  wherein the device is adapted to reject heat to at least two spaced apart heat sinks. 
     
     
         15 . A heat spreading device as set forth in  claim 1  wherein the device is adapted to reject heat to at least two spaced apart heat sinks. 
     
     
         16 . A heat spreading device as set forth in  claim 1  wherein the first and second conduits are free of fluid communication with each other.