Compact counterflow heat exchanger

Abstract

A geometric arrangement of components in a compact counter-flow heat exchanger that allows for either an increase in effectiveness at a set mass, or a reduction in heat exchanger mass at a set effectiveness, or a combination of the two. The geometric arrangement can be achieved by either tube bending at the level of piece part manufacture and subsequent care during the tube stacking process, or by elastic deformation of the tube stack at the time of bonding.

1 . A compact counterflow heat exchanger comprising: 
 a plurality of longitudinally extending and parallel fluid carrying tubes arranged in thermal contact with one another, each tube having at least one bend congruent to a bend in an immediately adjacent tube; and    a first heat exchange fluid flowing through any one tube in a direction opposite to a flow direction of a second heat exchange fluid flowing through an immediately adjacent tube, thereby establishing a counter-flow heat exchange relation between the first and second heat exchange fluids.    
   
   
       2 . The heat exchange system of  claim 1 , wherein the fluid carrying tubes comprise stainless steel.  
   
   
       3 . A microchannel recuperator including a core mass, comprising multiple layers in a vertical plane of multiple fluid carrying tube arranged adjacent to each together and a substrate layer disposed in a horizontal plane, alternating tubes having a longitudinal offset bend equal to at least the width of a tube, and fluid carrying counter-flow channels comprising alternate tube layers communicating across the entire horizontal plane thereof, whereby the fluid carrying tubes of the core mass are directly adjacent to the fluid carrying counter-flow channels.  
   
   
       4 . The microchannel recuperator of  claim 3 , wherein the offset bend in each tube is at least equal to ½ a dimension of any tube.  
   
   
       5 . The microchannel recuperator of  claim 4 , wherein the tubes comprise stainless steel.  
   
   
       6 . A method of making a heat exchanger comprising the steps of: 
 preparing a substrate layer of multiple square metal tubes arranged adjacent and physically attached to each other in a horizontal plane, each tube having a longitudinally extending offset bend;    configuring multiple layers in a vertical plane of multiple square metal tubes arranged adjacent to each other and the substrate layer in a horizontal plane and having interposed between each layer or multiple metal tubes Physically and communicating therewith a braze alloy thus forming a heat exchange core causing the braze alloy within the core to bond the multiple layers of multiple square metal tubes forming a core mass comprising in a vertical plane, multiple layers of multiple square metal tubes arranged adjacent and physically attached to each other and the substrate layer; forming in alternate tube layers counter-flow fluid channels communicating across the entire horizontal plane thereof;    providing the core mass with side containment shells  10  and manifolds in communication with the multiple square metal tube core mass and the counterflow counterflow channels; and    brazing the heat exchanger to bond parts thereof together.    
   
   
       7 . A method of thermal transfer comprising the steps of: 
 providing adjacent first and second fluid carrying tubes in heat exchange contact one with another;    forming an offset bend in each tube; and flowing a first thermal transfer fluid through the first fluid carrying tubes, and flowing a second thermal transfer fluid through the second fluid carrying tubes, respectively.    
   
   
       8 . The method of  claim 7 , further comprising the step of forming the offset bend in a distance equal to at least ½ a dimension of the first or second fluid carrying tube.  
   
   
       9 . The method of  claim 8 , further comprising the step of forming the first and second fluid carrying tubes of stainless steel.