Evaporator with enhanced condensate drainage

Abstract

An evaporator ( 10 ) with opposed pairs of generally vertically oriented flow tube surfaces ( 14 ) has corrugated air fins in which the tube surface spacing c, the interior radius r of a crest ( 20 ) joining adjacent pairs of fin walls ( 18 ), the fin pitch p separating adjacent crests ( 20 ), and the length l of louvers ( 22 ) cut out of the fin walls ( 18 ) bear the following relationship: 0≦r/c≦0.057, 0.89≦l/c≦1.01, and 0.29≦p/c≦0.43. This has been found to substantially improve condensate drainage, while not significantly penalizing heat transfer or air side pressure drop.

1 . In an evaporator ( 10 ) having substantially parallel, substantially vertically oriented refrigerant flow tubes ( 12 ), said tubes having opposed pair of surfaces ( 14 ) spaced apart by a distance c, between which tube surfaces ( 14 ) corrugated air fins ( 16 ) are located, said fin corrugations comprised of adjacent pairs of fin walls ( 18 ) joined at integral crests having an interior radius r and a fin pitch p, said fin walls ( 18 ) also comprising louvers ( 22 ) having a length l, characterized in that, 
 said tube surface spacing c, crest interior radius r, fin pitch p, and fin louver length l have the following relationship:   0 ≦r/c ≦0.0570.89 ≦l/c ≦1.010.29 ≦p/c ≦0.43   
     
     
         2 . In an evaporator ( 10 ) having substantially parallel, substantially vertically oriented refrigerant flow tubes ( 12 ), said tubes having opposed pair of surfaces ( 14 ) spaced apart by a distance c, between which tube surfaces ( 14 ) corrugated air fins ( 16 ) are located, said fin corrugations comprised of adjacent pairs of fin walls ( 18 ) joined at integral crests having an interior radius r, said fin walls ( 18 ) also comprising louvers ( 22 ) having a length l, characterized in that, 
 said tube surface spacing c, crest interior radius r, and fin louver length l have the following relationship:   0.25  mm≦r≦ 0.58  mm 0.89 ≦l/c ≦1.01