Refold heat exchanger

Abstract

A heat exchanger is disclosed that includes heat exchange elements made from a sheet having a plurality of hollow fins. In certain embodiments, the finned sheet is refolded and sealed at a first edge and a second edge to form an interior volume having an inlet manifold adjacent to the first edge, an outlet manifold adjacent to the second edge, and an opening that is opposite the refold of the finned sheet. In certain embodiments, a flow divider is located in the interior volume between the inlet manifold and the outlet manifold with interior tips of the hollow fins in contact with the flow divider. A base element is coupled over the opening of the interior volume, the base element comprising an inlet and an outlet positioned in fluid communication with the inlet manifold and the outlet manifold, respectively.

1 . A heat exchange element comprising:
 a folded sheet refolded and sealed at a first edge and a second edge to form an interior volume having an inlet manifold adjacent to the first edge, an outlet manifold adjacent to the second edge, and an opening opposite the refold of the folded sheet, wherein the folded sheet comprises a plurality of hollow fins;   a flow divider disposed in the interior volume between the inlet manifold and the outlet manifold, wherein a plurality of interior tips of the plurality of hollow fins is in contact with the flow divider; and   a base element coupled to a perimeter of the opening of the interior volume, the base element comprising an inlet and an outlet positioned in fluid communication with the inlet manifold and the outlet manifold, respectively.   
     
     
         2 . The heat exchange element of  claim 1 , wherein:
 the plurality of hollow fins are pinched along the first edge and the second edge so as to respectively form a first flat edge and a second flat edge; and   the folded sheet is sealed at the first flat edge and the second flat edge to form the interior volume.   
     
     
         3 . The heat exchange element of  claim 2 , wherein the first and second flat edges are parallel to and offset from a plane through the plurality of interior tips of the plurality of hollow fins. 
     
     
         4 . The heat exchange element of  claim 2 , wherein the sealing of the first and second flat edges is accomplished by one of the group of welding, brazing, soldering, and crimping. 
     
     
         5 . The heat exchange element of  claim 1 , wherein:
 the flow divider is spaced apart from the first and second edges;   the space within the interior volume between the flow divider and the first edge forms the inlet manifold; and   the space within the interior volume between the flow divider and the second edge forms the outlet manifold.   
     
     
         6 . The heat exchange element of  claim 5 , wherein:
 the flow divider comprises first and second surfaces that are substantially planar and parallel to each other; and   the interior tips of the plurality of hollow fins are in substantially continuous contact with the flow divider over the length of the flow divider.   
     
     
         7 . The heat exchange element of  claim 6 , wherein:
 the plurality of hollow fins and the flow divider form a plurality of isolated passages from the inlet manifold to the outlet manifold; and   substantially all of a flow path from the inlet manifold to the outlet manifold is through the plurality of passages of the fins.   
     
     
         8 . The heat exchange element of  claim 7 , wherein:
 each passage comprises an internal height and an internal base width;   a majority of the plurality of passages have a first height and a first base width; and   a ratio of the first height to the first base width is greater than 0.5.   
     
     
         9 . The heat exchange element of  claim 8 , wherein the ratio of the first height to the first base width is greater than 1.0. 
     
     
         10 . The heat exchange element of  claim 9 , wherein the ratio of the first height to the first base width is greater than 2.0. 
     
     
         11 . The heat exchange element of  claim 9 , wherein:
 the hollow fins each comprise a pair of side walls;   the side walls of a majority of the hollow fins are generally parallel to each other, thereby forming a generally rectangular passage having a width; and   the ratio of the height of the rectangular passage to the width of the rectangular passage is greater than 2.0.   
     
     
         12 . A refold heat exchanger for transferring heat from a first fluid to a second fluid, the heat exchanger comprising a plurality of heat exchange elements, each heat exchange element comprising:
 a folded sheet refolded and sealed at a first edge and a second edge to form an interior volume having an inlet manifold adjacent to the first edge, an outlet manifold adjacent to the second edge, and an opening opposite the refold of the folded sheet, wherein the folded sheet comprises a plurality of hollow fins;   a flow divider disposed in the interior volume between the inlet manifold and the outlet manifold, wherein a plurality of interior tips of the plurality of hollow fins is in contact with the flow divider; and   a base element coupled to a perimeter of the opening of the interior volume, the base element comprising an inlet and an outlet positioned in fluid communication with the inlet manifold and the outlet manifold, respectively,   wherein the first edge of a first heat exchange element is not sealed to the first edge of an adjacent second heat exchange element.   
     
     
         13 . The refold heat exchanger of  claim 12 , wherein:
 the plurality of hollow fins are pinched along the first edge and the second edge so as to respectively form a first flat edge and a second flat edge; and   the first flat edge and the second flat edge are sealed to form the interior volume.   
     
     
         14 . The refold heat exchanger of  claim 13 , wherein the first and second flat edges are parallel to and offset from a plane through the plurality of interior tips of the plurality of hollow fins. 
     
     
         15 . The refold heat exchanger of  claim 13 , wherein the sealing of the first and second flat edges is accomplished by one of the group of welding, brazing, soldering, and crimping. 
     
     
         16 . The refold heat exchanger of  claim 12 , wherein:
 the flow divider is spaced apart from the first and second edges;   the space within the interior volume between the flow divider and the first edge forms the inlet manifold; and   the space within the interior volume between the flow divider and the second edge forms the outlet manifold.   
     
     
         17 . The refold heat exchanger of  claim 16 , wherein:
 the flow divider comprises first and second surfaces that are substantially planar and parallel to each other; and   the interior tips of the plurality of hollow fins are in substantially continuous contact with the flow divider over the length of the flow divider.   
     
     
         18 . The refold heat exchanger of  claim 17 , wherein:
 the plurality of hollow fins and the flow divider form a plurality of isolated passages from the inlet manifold to the outlet manifold; and   substantially all of a flow path from the inlet manifold to the outlet manifold is through the plurality of passages of the fins.   
     
     
         19 . The refold heat exchanger of  claim 18 , wherein:
 each passage comprises an internal height and an internal base width;   a majority of the plurality of passages have a first height and a first base width; and   a ratio of the first height to the first base width is greater than 0.5.   
     
     
         20 . The refold heat exchanger of  claim 19 , wherein the ratio of the first height to the first base width is greater than 1.0. 
     
     
         21 . The refold heat exchanger of  claim 20 , wherein the ratio of the first height to the first base width is greater than 2.0. 
     
     
         22 . The refold heat exchanger of  claim 20 , wherein:
 the hollow fins each comprise a pair of side walls;   the side walls of a majority of the hollow fins are generally parallel to each other, thereby forming a generally rectangular passage having a width; and   the ratio of the height of the rectangular passage to the width of the rectangular passage is greater than 2.0.   
     
     
         23 . A method of forming a heat exchange element, the method comprising the steps of:
 folding a sheet of material to form hollow fins across a width of the sheet to form a folded sheet;   flattening a first edge and a second edge of the folded sheet to respectively form first and second flat edges;   lifting a portion of the first flat edge and a portion of the second flat edge;   refolding the folded sheet such that a first portion of the folded sheet is proximate to a second portion of the folded sheet to form a refolded sheet;   sealing the first flat edge and the second flat edge of the refolded sheet to form an interior volume comprising an inlet manifold adjacent to the first flat edge, an outlet manifold adjacent to the second flat edge, and an opening opposite the refold of the folded sheet; and   coupling a base element comprising an inlet and an outlet over the opening such that the inlet and outlet are in fluid communication with the inlet manifold and outlet manifold, respectively.   
     
     
         24 . The method  claim 23 , wherein the step of sealing is accomplished using a process chosen from the group of welding, brazing, soldering, and crimping. 
     
     
         25 . The method  claim 23 , wherein the step of coupling is accomplished using a process chosen from the group of welding, soldering, and crimping. 
     
     
         26 . The method  claim 23 , further comprising the step of:
 pre-welding the first flat edge and the second flat edge.   
     
     
         27 . The method  claim 23 , further comprising the step of:
 inserting a flow divider into the interior volume between inlet manifold and the outlet manifold.   
     
     
         28 . The method  claim 23 , wherein the step of folding comprises forming hollow fins comprising an internal height, an internal base width, and a ratio of the internal height to the internal base width greater than 0.5. 
     
     
         29 . The method of  claim 28 , wherein the ratio is greater than 1.0. 
     
     
         30 . The method of  claim 28 , wherein the step of folding comprises forming generally rectangular hollow fins comprising an internal width and a ratio of the internal height to the internal width greater than 2.0.