Micro-channel heat exchanger

Abstract

A heat exchanger comprising a process tube attached in heat conducting contact with a hydronic tube. The process tube has a plurality of hydraulically discrete internal passageways that extend through the process tube. The hydronic tube has at least one passageway that extends through the hydronic tube. Optionally, the process tube can be sandwiched between a pair of hydronic tubes so that two heat transfer surfaces on the process tube are in heat conducting contact with heat transfer surfaces on each of the hydronic tubes. Also optionally, the heat exchanger can include a plurality of process tubes that are sandwiched between a plurality of hydronic tubes with each process tube being disposed between a pair of hydronic tubes. The attached tubes can be shaped into a variety of configurations depending on the application in which the heat exchanger will be used.

What is claimed is:  
     
         1 . A flattened tube heat exchanger, the heat exchanger comprising: 
 a first and second flattened tube each having first and second ends with an intermediate portion therebetween and opposite heat transfer surfaces that extend between said first and second ends, said first tube having a plurality of hydraulically discrete internal passageways that extend through said first tube between said first and second ends of said first tube and allows a fluid to pass therethrough, said second tube having at least one internal passageway that extends through said second tube between said first and second ends of said second tube and allows a fluid to pass therethrough, and said second tube being disposed adjacent said first tube with said intermediate portions abutting and portions of said heat transfer surfaces that extend along said intermediate portions being in heat conducting contact; and    first and second pairs of manifolds, said first pair being attached to and in fluid communication with said first and second ends of said first tube so that a fluid can pass between said first pair via said plurality of passageways in said first tube, and said second pair being attached to and in fluid communication with said first and second ends of said second tube so that a fluid can pass between said second pair via said at least one passageway in said second tube.    
     
     
         2 . The heat exchanger of  claim 1 , wherein: 
 said at least one passageway is one of a plurality of passageways in said second tube with each passageway in said second tube being hydraulically discrete.    
     
     
         3 . The heat exchanger of  claim 2 , wherein: 
 said passageways in said first and second tubes each have a hydraulic diameter of less than 2.5 millimeters.    
     
     
         4 . The heat exchanger of  claim 1 , wherein: 
 said passageways in said first tube each have a hydraulic diameter of less than 2.5 millimeters.    
     
     
         5 . The heat exchanger of  claim 4 , wherein: 
 said passageways in said first tube each have a hydraulic diameter of less than approximately 2.0 millimeters.    
     
     
         6 . The heat exchanger of  claim 5 , wherein: 
 said passageways in said first tube each have a hydraulic diameter of less than approximately 1.5 millimeters.    
     
     
         7 . The heat exchanger of  claim 1 , wherein: 
 said intermediate portions extend sinuously between said first and second ends.    
     
     
         8 . The heat exchanger of  claim 1 , wherein: 
 said intermediate portions are coiled.    
     
     
         9 . The heat exchanger of  claim 1 , wherein: 
 said intermediate portions are generally straight.    
     
     
         10 . The heat exchanger of  claim 1 , wherein: 
 said intermediate portions have a single 90 degree bend and are generally L-shaped.    
     
     
         11 . The heat exchanger of  claim 1 , wherein: 
 said intermediate portions have two 90 degree bends and are generally U-shaped.    
     
     
         12 . The heat exchanger of  claim 1 , wherein: 
 said abutting intermediate portions are brazed together.    
     
     
         13 . The heat exchanger of  claim 1 , wherein: 
 said ends extend into slots in said manifolds.    
     
     
         14 . A flattened tube heat exchanger, the heat exchanger comprising: 
 a first, second, and third flattened tube each having first and second ends with an intermediate portion therebetween and opposite heat transfer surfaces that extend between said first and second ends, said first tube being disposed between said second and third tubes with said intermediate portions abutting and portions of said heat transfer surfaces that extend along said intermediate portions being in heat conducting contact, said first tube having a plurality of hydraulically discrete internal passageways that extend through said first tube between said first and second ends of said first tube and allow a fluid to pass therethrough, said second and third tubes each having at least one internal passageway that extends through said second and third tubes between said first and second ends of said second and third tubes and allows a fluid to pass therethrough; and    a plurality of manifolds, each manifold being attached to and in fluid communication with at least one end of said first and second ends.    
     
     
         15 . The heat exchanger of  claim 14 , wherein: 
 said plurality of manifolds are first and second pairs of manifolds, each manifold of said first pair being attached to and in fluid communication with different ends of said first tube and being disposed between said second and third tubes, and each manifold of said second pair being attached to different ends of said second tube and to different ends of said third tube.    
     
     
         16 . The heat exchanger of  claim 14 , wherein: 
 said at least one passageway in each of said second and third tubes is one of a plurality of passageways and each passageway in each of said second and third tubes is hydraulically discrete.    
     
     
         17 . The heat exchanger of  claim 16 , wherein: 
 each passageway in each of said tubes has a hydraulic diameter of less than 2.5 millimeters.    
     
     
         18 . The heat exchanger of  claim 14 , wherein: 
 each passageway in said first tube has a hydraulic diameter of less than 2.5 millimeters.    
     
     
         19 . The heat exchanger of  claim 18 , wherein: 
 each passageway in said first tube has a hydraulic diameter of less than approximately 2.0 millimeters.    
     
     
         20 . The heat exchanger of  claim 19 , wherein: 
 each passageway in said first tube has a hydraulic diameter of less than approximately 1.5 millimeters.    
     
     
         21 . The heat exchanger of  claim 14 , wherein: 
 said ends of said tubes diverge as said ends extend from said intermediate portions.    
     
     
         22 . A flattened tube heat exchanger, the heat exchanger comprising: 
 a plurality of first and second tubes each having first and second ends with an intermediate portion therebetween and opposite heat transfer surfaces that extend between said first and second ends, said first tubes each having a plurality of hydraulically discrete internal passageways that extend through said first tubes between said first and second ends of said first tubes and allow a fluid to pass therethrough, said second tubes each having at least one internal passageway that extends through said second tubes between said first and second ends of said second tubes and allows a fluid to pass therethrough, and each of said first tubes being disposed between two second tubes with said intermediate portions abutting and portions of said heat transfer surfaces that extend along said intermediate portions being in heat conducting contact; and    a plurality of manifolds, each manifold being attached to and in fluid communication with at least one end of said first and second ends.    
     
     
         23 . The heat exchanger of  claim 22 , wherein: 
 said plurality of manifolds are a plurality of first and second pairs of manifolds, each manifold of said first pairs, being attached to different ends of said first tubes and being disposed between said second tubes, and each manifold of said second pairs being attached to an end of at least one second tube of said plurality of second tubes.    
     
     
         24 . The heat exchanger of  claim 22 , wherein: 
 said at least one passageway in each second tube of said plurality of second tubes is one of a plurality of hydraulically discrete passageways.    
     
     
         25 . The heat exchanger of  claim 24 , wherein: 
 each passageway in each of said plurality of first and second tubes has a hydraulic diameter of less than 2.5 millimeters.    
     
     
         26 . The heat exchanger of  claim 22 , wherein: 
 each passageway in said plurality of first tubes has a hydraulic diameter of less than 2.5 millimeters.    
     
     
         27 . The heat exchanger of  claim 26 , wherein: 
 each passageway in said plurality of first tubes has a hydraulic diameter of less than approximately 2.0 millimeters.    
     
     
         28 . The heat exchanger of  claim 27 , wherein: 
 each passageway in said plurality of first tubes has a hydraulic diameter of less than approximately 1.5 millimeters.    
     
     
         29 . A method of making a flattened tube heat exchanger, the method comprising the steps of: 
 attaching an intermediate portion of a first flattened tube to an intermediate portion of a second flattened tube so that said intermediate portions are abutting and portions of heat transfer surfaces on said first and second tubes are in heat conductive contact;    attaching a first pair of manifolds to ends of said first tube so that each manifold of said first pair is attached to different ends of said first tube;    attaching a second pair of manifolds to ends of said second tube so that each manifold of said second pair is attached to different ends of said second tube; and    shaping said attached tubes into a predetermined configuration.    
     
     
         30 . The method of  claim 29 , wherein: 
 said first tube has a plurality of hydraulically discrete internal passageways that each have a hydraulic diameter of less than 2.5 millimeters and extend through said first tube between said ends of said first tube so that a fluid can pass therethrough.    
     
     
         31 . The method of  claim 29 , wherein the step of attaching an intermediate portion of a first tube includes: 
 disposing said first tube between a pair of second tubes with said intermediate portion of said first tube abutting intermediate portions of said second tubes and portions of heat transfer surfaces on said intermediate portion of said first tube being in heat conducting contact with portions of heat transfer surfaces on said intermediate portions of said pair of second tubes.    
     
     
         32 . The method of  claim 31 , wherein: 
 the step of attaching a first pair of manifolds includes disposing said first pair of manifolds between said pair of second tubes; and    the step of attaching a second pair of manifolds includes attaching each manifold of said second pair of manifolds to both tubes of said pair of second tubes so that each manifold of said second pair of manifolds is attached to different ends of each tube of said pair of second tubes.    
     
     
         33 . The method of  claim 29 , wherein: 
 the step of attaching an intermediate portion of a first tube includes disposing each first tube of a plurality of first tubes between two second tubes of a plurality of second tubes with intermediate portions of each tube abutting adjacent intermediate portions and portions of heat transfer surfaces on said intermediate portions of each tube being in heat conducting contact with adjacent portions of heat transfer surfaces on said adjacent intermediate portions;    the step of attaching a first pair of manifolds includes attaching a plurality of first pairs of manifolds to ends of said first tubes so that each first pair is attached to different ends of a single first tube; and    the step of attaching a second pair of manifolds includes attaching a plurality of second pairs of manifolds to ends of said second tubes so that each second pair is attached to different ends of at least one second tube of said plurality of second tubes.    
     
     
         34 . The method of  claim 29 , wherein the step of shaping said attached tubes includes: 
 shaping said attached tubes so that said intermediate portions extend sinuously between said ends of said tubes.    
     
     
         35 . The method of  claim 29 , wherein the step of shaping said attached tubes includes: 
 shaping said attached tubes so that said intermediate portions are coiled.    
     
     
         36 . The method of  claim 29 , wherein: 
 the step of attaching said intermediate portions includes brazing said abutting intermediate portions;    the step of attaching a first pair of manifolds includes brazing said first pair of manifolds to said ends of said first tube; and    the step of attaching a second pair of manifolds includes brazing said second pair of manifolds to said ends of said second tube.