Passive Thermal Management System

Abstract

A traditional passive thermal management system can only be used effectively in a single orientation because it relies on the buoyancy of the heated air to create natural convection. A passive thermal management system is provided which includes means for transferring heat away from a heat source ( 10 ) in any orientation. The system comprises a heat pipe ( 14 ) which is thermally coupled to the heat source ( 10 ). The heat pipe ( 14 ) is capable of transferring heat away from the heat source ( 10 ), wherein this heat is transferred along the length of the heat pipe ( 14 ). Thermally coupled to the heat pipe ( 14 ) is a fin system ( 12 ), which provides a means for extraction of the heat from the heat pipe ( 14 ) and transfer of this heat to the environment thereby dissipating the heat generated at the heat source ( 10 ). The fin system ( 12 ) is configured to provide a desired level of heat transfer to the environment independent of the orientation of the thermal management system.

1 . A passive thermal management system for dissipating heat generated by a heat source, the thermal management system comprising:
 (a) one or more heat pipes each having a length, each heat pipe thermally connected to the heat source, each heat pipe for transferring heat along its length away from the heat source; and   (b) a fin system thermally coupled to the one or more heat pipes, the fin system extracting heat from the one or more heat pipes and dissipating the heat therefrom, the fin system configured to provide a desired level of heat dissipation independent of orientation of the thermal management system.   
     
     
         2 . The passive thermal management system according to  claim 1 , wherein said fin system comprises a plurality of fins, said fins aligned about parallel with the length of the one or more heat pipes. 
     
     
         3 . The passive thermal management system according to  claim 1 , wherein said fin system comprises a plurality of fins, said plurality of fins positioned in a stacked configuration with a predetermined separation therebetween. 
     
     
         4 . The passive thermal management system according to  claim 3 , wherein said fins are aligned about perpendicular with the length of the one or more heat pipes. 
     
     
         5 . The passive thermal management system according to  claim 3 , wherein each of said fins comprise one or more primary holes therein for insertion of a heat pipe. 
     
     
         6 . The passive thermal management system according to  claim 3 , wherein each of said fins comprise one or more secondary holes therein for enabling fluid to pass therethrough. 
     
     
         7 . The passive thermal management system according to  claim 3 , wherein said fins are configured in a shape selected from the group comprising planar, bi-planar, curved, conical, cylindrical and frusto-conical. 
     
     
         8 . The passive thermal management system according to  claim 3 , wherein said fins are have a cross section which comprises two sloped portions and one flat portion. 
     
     
         9 . The passive thermal management system according to  claim 3 , wherein said fins are formed from a material selected from the group comprising aluminium, copper, metal, alloy, ceramic, metal ceramic composite and thermally conductive polymer. 
     
     
         10 . The passive thermal management system according to  claim 3 , wherein said fins are formed from two or more thermally conductive materials. 
     
     
         11 . The passive thermal management system according to  claim 1 , wherein the fin system is thermally coupled to the one or more heat pipes using a method selected from the group comprising welding, brazing, interference connection, epoxy, soldering and thermally conductive adhesive. 
     
     
         12 . The passive thermal management system according to  claim 3 , wherein each of said fins are configured as a bi-planar fin comprising a centrally located secondary hole therein. 
     
     
         13 . The passive thermal management system according to  claim 12 , wherein each of said fins comprise one or more holes therein, each of the one or more holes for insertion of one of the one or more heat pipes. 
     
     
         14 . The passive thermal management system according to  claim 12 , wherein each the bi-planar fin has two planes which an intersection angle therebetween, said intersection angle ranges between about 40 degrees and about 140 degrees. 
     
     
         15 . The passive thermal management system according to  claim 13 , wherein said intersection angle ranges between about 60 degrees and about 120 degrees. 
     
     
         16 . The passive thermal management system according to  claim 13 , wherein said intersection angle ranges between about 80 degrees and 100 degrees. 
     
     
         17 . The passive thermal management system according to  claim 1 , wherein the passive thermal management system is coupled to a lighting device and wherein the fin system is configured as a portion of a housing for the lighting device. 
     
     
         18 . The passive thermal management system according to  claim 17 , wherein the fin system is configured to form an entire housing for the lighting device.