Thermal-control, truss-plate apparatus and method

Abstract

Modular thermal truss plates carry heat in multiple directions. Framing around an array of flat heat pipes provides mechanical and thermal connections to other truss plates, and a base, such as a satellite, thereby supporting thermally active equipment. Walls sandwich banks of flat heat pipes and may bond to a honey comb, metal core conducting heat between multiple walls. Each bank of flat heat pipes passes heat best in one direction, and may be formed of corrugated copper sheets spaced apart by a metal mesh, such as an expanded metal or screen, also stamped or otherwise formed into a corrugated configuration. Joining methods (e.g., brazing, soldering, etc.) increase stiffness, pressure containment, and strength, by binding the two layers of metal sheet to one another.

What is claimed and desired to be secured by United States Letters Patent is: 
     
         1 . A method comprising:
 providing a plurality of heat pipes, each of the heat pipes thereof having a heated region, cooled region, working fluid, vapor path, and condensate path, all within a single contiguous sealed volume, wherein the vapor path carries a vapor of the working fluid from the heated region toward the cooled region and the condensate path carries a condensate of the working fluid from the cooled region to the heated region, the plurality of heat pipes characterized by a first set of heat pipes and a second set of heat pipes, each heat pipe thereof having an interior surface, exterior surface, wherein a thickness, width, and length, thereof define a thickness, a width, and a length direction, respectively;   arranging a first bank, comprising the first set, having the heat pipes thereof arranged to be co-planar, parallel, and adjacent one another in the respective width directions corresponding thereto; and   arranging a second bank, comprising the second set, having the heat pipes thereof arranged to be co-planar, parallel, and adjacent one another in the respective width directions corresponding to the heat pipes of the second set, while being orthogonal to the first set;   wherein providing a plurality of heat pipes comprises providing first and second layers of foil, each layer being corrugated, providing a mesh corrugated to provide channels defined by the corrugations, and bonding the mesh between the first and second layers of foil to support a vapor pressure of the working fluid between the first and second layer.   
     
     
         2 . The method of  claim 1 , further comprising:
 connecting a core between the first and second banks to conduct heat from the first bank to the second bank.   
     
     
         3 . The method of  claim 1 , further comprising:
 providing a first skin comprising a first planar structure parallel to the first bank;   bonding the first skin to the first bank, opposite the second bank, to support a bending load;   providing a second skin, comprising a second planar structure parallel to the second bank and first bank; and   bonding the second skin to the second bank, opposite the first bank, to support a bending load.   
     
     
         4 . The method of  claim 1 , wherein a first aspect ratio of the first thickness to first width is less than one and a second aspect ratio of the first width to first length is less than one. 
     
     
         5 . The method of  claim 4 , wherein at least one of the first and second aspect ratios is less than 10. 
     
     
         6 . The method of  claim 1 ,
 wherein the inner and outer surfaces of each heat pipe of the plurality of heat pipes further define therebetween a first wall, formed as a corrugated sheet wherein corrugations form, in both the inner and outer surfaces thereof, lands and grooves alternating therealong in the width direction corresponding thereto, the grooves on the inner surface carrying the condensate of the working fluid along the inner surface.   
     
     
         7 . The method of  claim 6 , wherein each heat pipe further comprises:
 a second wall;   a spacer positioned on the lands to space apart the first and second walls.   
     
     
         8 . The method of  claim 7 , wherein:
 the spacer is corrugated to form channels between the walls carrying a vapor phase of the working fluid; and   the spacer is perforated to provide fluid communication between the grooves on the inner surface and the channels.   
     
     
         9 . The method of  claim 8 , further comprising:
 increasing effective thermal conductivity between the grooves on an inner surface of the walls by filling the grooves on an outer surface of the walls with a filler.   
     
     
         10 . A method comprising:
 providing a plurality of heat pipes, each heat pipe thereof having a thickness, width, and length, defining thickness, width, and length directions, respectively;   the providing a plurality of heat pipes, wherein each of the heat pipes is formed as a first layer of foil, corrugated to form lands and grooves on both an inner surface thereof and on an outer surface thereof;   the providing a plurality of heat pipes, wherein each of the heat pipes further comprises a mesh, the mesh being porous and corrugated, acting as a support structure in contact with the foil, and controlling hoop stresses in grooves on the inner surface by bonding the mesh to the lands on the inner surface;   arranging a first bank, by selecting from among the plurality of heat pipes and arranging therefrom a first set of heat pipes, co-planar with each other and adjacent in the respective width directions thereof; and   arranging a second bank, by selecting from among the plurality of heat pipes and arranging therefrom a second set of heat pipes co-planar with each other and orthogonal to the first bank.   
     
     
         11 . The method of  claim 10 , further comprising:
 selecting a hydraulic diameter of the grooves based on a vapor pressure of a working fluid carried within the mesh.   
     
     
         12 . The method of  claim 11 , further comprising:
 introducing the working fluid into the corrugations of the mesh;   carrying the condensate in a first direction along the grooves on the inner surface operating as capillary channels; and   carrying the vapor in the channels formed by the corrugations of the mesh opening away from the lands and grooves on the inner surface.   
     
     
         13 . The method of  claim 12 , further comprising:
 forming a pressure vessel by bonding a second layer of the foil to the mesh, opposite the first layer of the foil.   
     
     
         14 . The method of  claim 13 , further comprising:
 forming a plurality of the pressure vessels configured as flat heat pipes;   forming a thermal wall of the plurality of pressure vessels;   filling the grooves on the outer surfaces of the pressure vessels with a material selected to increase the thermal conductivity through those grooves; and   bonding a structural skin to, and corresponding to, each of the outer surfaces.   
     
     
         15 . A method comprising:
 providing a plurality of heat pipes, each heat pipe thereof having a thickness, width, and length, defining thickness, width, and length directions, respectively;   the providing a plurality of heat pipes, wherein each of the heat pipes is formed as a first layer of foil, corrugated to form lands and grooves on both an inner surface thereof and on an outer surface thereof;   the providing a plurality of heat pipes, wherein each of the heat pipes comprises a core comprising a conductor of heat extending continuously in a first direction from a first end to a second end;   the providing a plurality of heat pipes, wherein the conductor occupies less than about ten percent of the volume of the core;   the providing a plurality of heat pipes, wherein a first bank of heat pipes is formed by selecting and arranging, from the plurality of heat pipes, a first set of heat pipes constituting the first bank, connected to the first end and oriented to permit flow of a working fluid therewithin principally in a second direction, orthogonal to the first direction;   the providing a plurality of heat pipes, wherein a second bank of heat pipes is formed by selecting and arranging, from the plurality of heat pipes, a second set of heat pipes constituting the second bank, connected to the second end and oriented to permit fluid flow of the working fluid therewithin principally in a third direction orthogonal to the first and second directions;   the providing a plurality of heat pipes, wherein each of the first bank, second bank, and core has a section modulus, and the core has a length selected to increase the section modulus of a combination of the first bank, second bank, and core to a value greater than that of any of the first bank, second bank, and core taken individually;   providing a heat exchange path from a first location in the first bank, through the core, to a second location in the second bank;   wherein the heat pipes constituting the first set are co-planar with one another and adjacent to one another in the width directions corresponding thereto; and   wherein the heat pipes constituting the second set are co-planar with one another, adjacent one another in the width directions corresponding thereto, and are orthogonal to the heat pipes constituting the first set.   
     
     
         16 . The method of  claim 15 , wherein:
 the heat exchange path has an effective thermal conductivity of energy per unit distance traveled per unit of time per unit of temperature difference effective to transfer heat between the first location to the second location; and   the effective thermal conductivity is greater than the actual thermal conductivity of each material in the heat exchange path.   
     
     
         17 . The method of  claim 16 , wherein the effective thermal conductivity is greater than the actual thermal conductivity of at least one of copper and aluminum. 
     
     
         18 . The method of  claim 17 , wherein the effective thermal conductivity is greater than the actual thermal conductivity of all metals that are chemically stable in ambient air. 
     
     
         19 . The method of  claim 16 , wherein the effective thermal conductivity is greater than the actual thermal conductivity of all metals.