Frost tolerant fins

Abstract

A heat exchanger assembly for thermally conditioning a stream of air. The assembly includes a first and second manifolds extending in spaced and parallel relationship. A plurality of tubes extend transversly between the manifolds to establish fluid communication therebetween. A plurality of corrugated air fins is disposed between adjacent tubes with the cross-section of each air fin presenting a plurality of legs extending transversly between the flat sides of adjacent tubes. Each leg defines a plurality of front louvers including a leading half louver disposed adjacent the front edge of the leg and a plurality of leading louvers spaced from each other and from the leading half louver. A plurality of smaller trailing louvers are spaced from the leading louvers. A plurality of rear louvers being spaced from each other is disposed between the trailing louvers and the rear edge of each leg.

1 . A heat exchanger assembly for heating and/or cooling a stream of air comprising:
 a plurality of tubes extending in parallel and spaced relationship with each other;   a plurality of air fins disposed between and engaging adjacent tubes and having a front edge and a back edge;   said air fins defining a plurality of front louvers being spaced from each other and adjacent said front edge to define a plurality of front air gaps;   said front louvers including at least one leading louver having a predetermined leading louver width and at least one trailing louver having a trailing louver width;   said leading louver width being greater than said trailing louver width; and   said leading louver width ranging from 1.3 to 2.5 mm.   
   
   
       2 . The assembly as set forth in  claim 1  wherein said leading louver width is further defined as ranging from 1.5 to 2.0 mm. 
   
   
       3 . The assembly as set forth in  claim 1  wherein said leading louver width is further defined as ranging from 1.9 to 2.0 mm. 
   
   
       4 . The assembly as set forth in  claim 1  wherein said trailing louvers have a predetermined trailing louver width ranging from 0.9 to 1.5 mm. 
   
   
       5 . The assembly as set forth in  claim 1  wherein said trailing louvers have a predetermined trailing louver width ranging from 1.00 to 1.25 mm. 
   
   
       6 . The assembly as set forth in  claim 5  wherein said trailing louver width is further defined as 1.14 mm. 
   
   
       7 . The assembly as set forth in  claim 1  wherein the cross-section of each of said air fins presents a plurality of legs extending transversly between said adjacent tubes and defining a plurality of air channels for the flow of air between adjacent legs of said air fins. 
   
   
       8 . The assembly as set forth in  claim 7  wherein each of said legs of said air fins includes a plurality of rear louvers being spaced from each other and adjacent said rear edge to define a plurality of rear air gaps in each of said legs of said air fin for conveying air from said second air channel to said first air channel. 
   
   
       9 . The assembly as set forth in  claim 8  wherein each of said legs of said air fins includes a center rib disposed between said front louvers and said rear louvers for directing airflow delivered from said first air channel to said second air channel by said front louvers back to said first air channel. 
   
   
       10 . The assembly as set forth in  claim 9  wherein said center rib has a center portion extending parallel to said legs of said fins and has a front side extending transversely from said center portion toward said front louvers to define one of said front air gaps adjacent to said front side and has a rear side opposite of said front side and extending transversely from said center portion toward said rear louvers to define one of said rear air gaps adjacent to said rear side. 
   
   
       11 . The assembly as set forth in  claim 8  wherein said rear louvers have a rear louver width ranging from 0.8 to 1.5 mm. 
   
   
       12 . The assembly as set forth in  claim 8  wherein said rear louvers are disposed at a predetermined rear louver angle ranging from 20 to 50 degrees. 
   
   
       13 . The assembly as set forth in  claim 8  wherein said rear louvers are disposed at a rear louver angle ranging from 35 to 45 degrees. 
   
   
       14 . The assembly as set forth in  claim 1  wherein said front louvers are disposed at a front louver angle ranging from 20 to 50 degrees. 
   
   
       15 . The assembly as set forth in  claim 1  wherein said front louvers are disposed at a front louver angle ranging from 35 to 45 degrees. 
   
   
       16 . The assembly as set forth in  claim 1  further including a first manifold and a second manifold extending in spaced and parallel relationship with said first manifold; and
 each of said tubes extending between a first tube end engaging said first manifold and a second tube end engaging said second manifold.   
   
   
       17 . The assembly as set forth in  claim 16  wherein said first manifold defines a plurality of first tube slots spaced from each other and engaging said tubes. 
   
   
       18 . The assembly as set forth in  claim 17  wherein said second manifold defines a plurality of second tube slots being spaced to correspond with said first tube slots of said first manifold. 
   
   
       19 . The assembly as set forth in  claim 18  wherein said first tube end of each of said tubes extends into one of said first tube slots of said first manifold to establish fluid communication between said first manifold and said tubes. 
   
   
       20 . The assembly as set forth in  claim 19  wherein said second tube end of each of said tubes extends into said corresponding second tube slot of said second manifold to establish fluid communication between said second manifold and said tubes. 
   
   
       21 . The assembly as set forth in  claim 1  wherein each of said tubes has a cross-section presenting flat sides interconnecting a round front and a round back. 
   
   
       22 . The assembly as set forth in  claim 21  wherein each of said tubes includes at least one tube divider dividing each tube into first and second passages and extending between said first and second tube slots. 
   
   
       23 . The assembly as set forth in  claim 21  wherein said legs of each of said fins are interconnected by bases engaging said flat sides of alternating tubes to present a serpentine pattern extending between said first and second manifolds. 
   
   
       24 . The assembly as set forth in  claim 1  further including a leading half louver disposed adjacent said front edge of each of said air fins. 
   
   
       25 . The assembly as set forth in  claim 24  wherein said leading half louver has a leading half louver width ranging from 0.75 to 1.50 mm. 
   
   
       26 . A heat exchanger assembly for heating and/or cooling a stream of air comprising:
 a first manifold presenting a plurality of first tube slots spaced from each other;   a second manifold extending in spaced an parallel relationship with said first manifold and defining a plurality of second tube slots being spaced to correspond with said first tube slots of said first manifold;   a plurality of tubes extending in parallel and spaced relationship with each other between first and second tube ends;   said first tube end of each tube extending into one of said first tube slots of said first manifold to establish fluid communication between said first manifold and said tubes;   said second tube end of each tube extending into said corresponding second tube slot of said second manifold to establish fluid communication between said second manifold and said tubes;   each of said tubes having a cross-section presenting flat sides interconnecting a round front and a round back;   each of said tubes including at least one tube divider dividing each tube into first and second passages and extending between said first and second tube slots;   a plurality of air fins disposed between and engaging said flat sides of adjacent tubes and having a front edge adjacent said round front of said tubes and a back edge adjacent said round back of said tubes;   the cross-section of each of said air fins presenting a plurality of legs extending transversely between said adjacent flat sides of said tubes and interconnected by bases engaging said flat sides of alternating tubes to present a serpentine pattern extending between said first and second manifolds and defining a plurality of air channels for the flow of air between adjacent legs of said air fins;   each of said legs of said air fins defining a plurality of front louvers including a leading half louver and a plurality of rear louvers including a trailing half louver and a center rib disposed between said front and rear louvers;   said plurality of front louvers spaced from each other and disposed at a predetermined front louver angle to define a plurality of front air gaps in each of said legs of said air fins for conveying air from a first air channel on one side of said leg to a second air channel on the other side of said leg;   said plurality of rear louvers being spaced from each other and disposed adjacent said rear edge of said air fin at a predetermined rear louver angle to define a plurality of rear air gaps in each of said legs of said air fin for conveying air from said second air channel to said first air channel;   said center rib being disposed between said front and rear louvers for directing airflow delivered from said first air channel to said second air channel by said front louvers back to said first air channel;   said center rib having a center portion extending parallel to said legs of said fins and having front side extending transversely from said center portion toward said front louvers to define one of said front air gaps adjacent to said front side and having a rear side opposite from said front side and extending transversely from said center portion toward said rear louvers to define one of said rear air gaps adjacent to said rear side;   said leading half louver being disposed adjacent said front edge of each leg of said air fin and said trailing half louver being disposed adjacent said rear edge of each leg of said air fin;   said front louvers including a plurality of leading louvers spaced from said leading half louver and having a predetermined leading louver width;   said front louvers including a plurality of trailing louvers disposed between said leading louvers and said center rib and having a predetermined trailing louver width;   said rear louvers having a rear louver width;   said leading louver width of said leading louvers being wider than said trailing louver width of said trailing louvers; and   said leading half louver width ranging from 0.75 to 1.50 mm;   said leading louver width ranging from 1.3 to 2.5 mm;   said trailing louver width ranging from 1.00 to 1.25 mm;   said rear louver width ranging from 0.8 to 1.5 mm; and   said front and rear louver angles ranging from 35 to 45 degrees.