Multichannel Heat Exchanger

Abstract

Heating, ventilation, air conditioning, and refrigeration (HVAC&R) systems and heat exchangers are provided that include multichannel tube and fin configurations designed to promote the release of condensate. The multichannel tubes may have a curved, round, or airfoil shape, and may be used with plate or corrugated fins. In certain embodiments, corrugated fins may be brazed to multichannel tubes and then trimmed to form individual fin structures. Double header configurations also may be employed.

1 . A heat exchanger comprising:
 a first manifold;   a second manifold;   a plurality of multichannel tubes in fluid communication with the first and second manifolds, being configured to receive an external fluid flowing across a width dimension from a leading edge to a trailing edge, and the multichannel tubes each having an airfoil shape configured to direct condensate of the external fluid from the leading edge to the trailing edge; and   a plurality of generally parallel flow paths disposed within each multichannel tube and extending lengthwise through each multichannel tube.   
   
   
       2 . The heat exchanger of  claim 1 , wherein the airfoil shape is symmetrical, positively cambered, or negatively cambered. 
   
   
       3 . The heat exchanger of  claim 1 , wherein the generally parallel flow paths comprise different size flow paths. 
   
   
       4 . The heat exchanger of  claim 1 , wherein the generally parallel flow paths comprise relatively small flow paths disposed near the leading and trailing edges and relatively large flow paths disposed near a center section of each multichannel tube. 
   
   
       5 . The heat exchanger of  claim 1 , wherein the generally parallel flow paths are disposed along a mean camber line of the airfoil shape. 
   
   
       6 . The heat exchanger of  claim 1 , wherein at least some of the generally parallel flow paths are disposed above and/or below a mean camber line of the airfoil shape. 
   
   
       7 . The heat exchanger of  claim 1 , wherein each of the multichannel tubes comprises a cross section that generally tapers outwardly from a maximum thickness towards the leading edge and towards the trailing edge. 
   
   
       8 . The heat exchanger of  claim 1 , wherein a mean camber line of the airfoil shape slopes more steeply towards the leading edge and less steeply towards the trailing edge. 
   
   
       9 . A heat exchanger comprising:
 a first manifold;   a second manifold;   a plurality of multichannel tubes in fluid communication with the first and second manifolds, the multichannel tubes each having a transversely curved cross sectional profile extending from a leading edge to a trailing edge and being configured to receive an external fluid flowing across the transversely cross sectional profile from the leading edge to the trailing edge; and   a plurality of generally parallel flow paths disposed within each multichannel tube and extending lengthwise through each multichannel tube.   
   
   
       10 . The heat exchanger of  claim 9 , wherein the transversely curved cross sectional profile is configured to promote drainage of condensate of the external fluid from the multichannel tubes. 
   
   
       11 . The heat exchanger of  claim 9 , wherein the transversely curved cross sectional profile comprises an asymmetrical curvature. 
   
   
       12 . The heat exchanger of  claim 9 , comprising fins for transferring heat to or from the internal fluid flowing through the flow paths during operation, wherein the fins comprise openings encircling the transversely curved cross sectional profiles. 
   
   
       13 . The heat exchanger of  claim 9 , wherein the multichannel tubes are aligned in two columns within the heat exchanger and wherein the multichannel tubes of each column are staggered with respect to the multichannel tubes of the other column. 
   
   
       14 . The heat exchanger of  claim 9 , wherein each of the multichannel tubes has a generally convex upper surface and a generally concave lower surface. 
   
   
       15 . A heat exchanger comprising:
 a first manifold;   a second manifold;   a plurality of multichannel tubes configured to direct a fluid from the first manifold to the second manifold; and   a plurality of fins disposed between the multichannel tubes, each of the fins having wall segments separated by alternating bends attached to the multichannel tubes and having openings disposed through the alternating bends to form a path through the fins.   
   
   
       16 . The heat exchanger of  claim 15 , wherein the wall segments are generally parallel to one another. 
   
   
       17 . The heat exchanger of  claim 15 , wherein the wall segments are angled with respect to one another. 
   
   
       18 . The heat exchanger of  claim 15 , wherein the wall segments are curved toward the openings. 
   
   
       19 . The heat exchanger of  claim 15 , wherein each of the openings extends through one of the bends and through a portion of the wall segments adjoining the bend. 
   
   
       20 . The heat exchanger of  claim 15 , wherein the path extends through the fins generally parallel to a length of the multichannel tubes. 
   
   
       21 . A method for making heat exchanger fins, the method comprising:
 disposing corrugated fins having wall segments separated by alternating bends between multichannel tubes such that the bends extend beyond the multichannel tubes and the edges of the wall segments are disposed against the multichannel tubes;   securing the edges of the wall segments to the multichannel tubes to permanently join the wall segments to the multichannel tubes; and   trimming the corrugated fins to remove the alternating bends from the corrugated fins and to create openings between the wall segments.   
   
   
       22 . The method of  claim 21 , wherein trimming the corrugated fins comprises shearing the bends from the corrugated fins to produce individual wall segments. 
   
   
       23 . The method of  claim 21 , comprising creating openings through the edges of the wall segments. 
   
   
       24 . The method of  claim 21 , wherein the wall segments are curved. 
   
   
       25 . The method of  claim 21 , wherein the wall segments are angled. 
   
   
       26 . A heat exchanger comprising:
 a first manifold having a baffle disposed lengthwise through the first manifold to divide the first manifold into a first section configured to receive a first phase of a refrigerant and a second section configured to receive a second phase of the refrigerant;   a second manifold;   a first set of multichannel tubes in fluid communication with the first section and the second manifold and configured to direct an external fluid entering the heat exchanger across the first set of multichannel tubes;   a second set of multichannel tubes in fluid communication with the second section and the second manifold and configured to direct the external fluid exiting the first set of multichannel tubes across the second set of multichannel tubes; and   a plurality of generally parallel flow paths disposed within each multichannel tube of the first and second sets and extending lengthwise through each multichannel tube to direct the refrigerant from the first manifold to the second manifold.   
   
   
       27 . The heat exchanger of  claim 26 , wherein the heat exchanger comprises an evaporator, the first phase comprises a vapor phase, and the second phase comprises a liquid phase. 
   
   
       28 . The heat exchanger of  claim 26 , wherein tubes of the first set of multichannel tubes comprise generally straight ends extending into the first section and wherein tubes of the second set of multichannel tubes comprise generally angular ends extending into the second section. 
   
   
       29 . The heat exchanger of  claim 26 , wherein tubes of the first set of multichannel tubes and the second set of multichannel tubes each comprise a transversely curved cross sectional profile. 
   
   
       30 . The heat exchanger of  claim 29 , wherein the tubes of the first and second sets of multichannel tubes curve in alternate directions. 
   
   
       31 . The heat exchanger of  claim 26 , wherein tubes of the first and second sets of multichannel tubes are staggered with respect to one another. 
   
   
       32 . The heat exchanger of  claim 26 , wherein tubes of the first and second sets of multichannel tubes comprise airfoil shapes.