Evaporator designs for achieving high cooling performance at high superheats

Abstract

An evaporator includes plates disposed in pairs in first and second groups, along spaced tanks. Dimples extend from the interior portions in the first group, and interior fins are disposed against the interior portions of the second group. The dimples enhance the distribution of liquid refrigerant in the passageways and the thermal energy exchange between ambient air and an upstream, low vapor quality flow of fluid passing between upstream and downstream side edges, of the first group of plates. The evaporator also eliminates the tonal noise or whistle under certain transient operating conditions.

1 . A laminate-type evaporator comprising: 
 a first tank;    a second tank;    a plurality of plates each having upstream and downstream side edges in spaced relation to one another and an interior portion recessed relative to said side edges;    said plates disposed in pairs with said side edges, of each pair in abutting engagement with one another and said interior portions defining a passageway between each pair of plates;    said pairs spaced along said tanks, in first and second groups, with said passageways in fluid communication with said first and second tanks, for permitting a fluid to flow between said tanks through said passageways for allowing a thermal energy exchange between the fluid and a cross-flow of air through said first and second groups from said upstream side edge to said downstream side edge;    a plurality of dimples extending from said interior portions of said first group of plates into said passageways for enhancing the distribution of liquid refrigerant in said passageways and the thermal energy exchange between the fluid and the cross-flow of air between said upstream and downstream side edges and    a plurality of interior fins disposed against said interior portions and extending to said upstream and downstream side edges of said second group of plates for enhancing the thermal energy exchange between the fluid and the cross-flow of air between said upstream and downstream side edges of said second group whereby said dimples of said first group of plates enhance the distribution of liquid refrigerant and the thermal energy exchange with an upstream flow of the low vapor quality fluid passing between said upstream and said downstream side edges of said first group of plates while said fins of said second group of plates enhance the thermal energy exchange with a downstream flow of the high vapor quality fluid passing between said upstream and said downstream side edges, of said second group of plates.    
   
   
       2 . An evaporator as recited in  claim 1  wherein each of said plates includes a pair of tubular projections with said interior portion interconnecting said pair of tubular projections in fluid communication therewith and said pairs of tubular projections on said plates in abutting engagement with one another to define said first and second tanks.  
   
   
       3 . An evaporator as recited in  claim 2  wherein said plates include upper and lower edges interconnecting said upstream and downstream side edges with said first tank disposed adjacent said upper edges and said second tank disposed adjacent said lower edges.  
   
   
       4 . An evaporator as recited in  claim 2  wherein said plates include upper and lower edges interconnecting said upstream and downstream side edges with said first and second tanks disposed adjacent said upper edges.  
   
   
       5 . An evaporator as recited in  claim 4  wherein each of said interior portions of said second group of plates include a central rib extending from said interior portion to define a first recess adjacent said upstream said edge, a second recess adjacent said downstream side edge and a return recess interconnecting said first and second recesses, said central ribs in each of said adjacent pairs of said plates in said second group in abutting engagement with one another wherein said recesses define a plurality of U-shaped channels interconnecting said first and second tanks.  
   
   
       6 . An evaporator as recited in  claim 5  wherein said interior fins on each of said plates in said second group include a first fin group disposed against said first recess.  
   
   
       7 . An evaporator as recited in  claim 5  wherein said interior fins on each of said plates in said second group include a second fin group disposed against said second recess.  
   
   
       8 . An evaporator as recited in  claim 7  and including a plurality of second dimples extending from said interior portions of said second group of plates into said passageways for enhancing the distribution of liquid refrigerant and the thermal energy exchange between the fluid flowing therethrough and the cross-flow of air.  
   
   
       9 . An evaporator as recited in  claim 8  wherein said second dimples extend from said interior portions intermediate said first and second fin groups.  
   
   
       10 . An evaporator as recited in  claim 9  wherein said second dimples extend from said return recesses.  
   
   
       11 . An evaporator as recited in  claim 1  including at least two groups of said second group of plates including said fins with four or more groups of said first group of plates.  
   
   
       12 . An evaporator as recited in  claim 1  including one or two groups of said second group of plates including said fins with four or more groups of said first group of plates.