Plate fin-tube heat exchanger and refrigeration-and-air-conditioning system including the same

Abstract

A plate fin-tube heat exchanger is provided in which surfaces of flat tubes and fins each have concavities and convexities in which a length between one of peak portions that has the smallest height and one of trough portions that has the smallest depth is 10 μm or larger.

1 . A plate fin-tube heat exchanger in which flat tubes each having a flat cross-sectional shape whose long sides are linear and whose short sides are curved in a semicircular manner are fitted in notches provided in fins,
 wherein a surface of at least either one of each of the flat tubes and each of the fins has
 a plurality of concavities and convexities in which a difference in height between one of peak portions that has a smallest height and one of trough portions that has a smallest depth is 10 μm or larger, and 
 a foreign substance having a higher melting point than a weld material used for welding the flat tubes and the fins is added to the weld material in advance. 
   
     
     
         2 . The plate fin-tube heat exchanger of  claim 1 ,
 wherein the concavities and convexities are formed such that
 an angle formed between the surface of at least either one of each of the flat tubes and each of the fins and a line is 60 degrees or smaller, the line being tangent to an end of a portion of a dewdrop being present in contact with the surface of at least either one of each of the flat tubes and each of the fins. 
   
     
     
         3 . The plate fin-tube heat exchanger of  claim 1 ,
 wherein the concavities and convexities are
 provided in an oxide film that is formed by heat generated when the flat tubes and the fins are welded to each other. 
   
     
     
         4 . (canceled) 
     
     
         5 . (canceled) 
     
     
         6 . A refrigeration-and-air-conditioning system,
 wherein the plate fin-tube heat exchanger of  claim 1  is used as an evaporator.   
     
     
         7 . A plate fin-tube heat exchanger in which flat tubes each having a flat cross-sectional shape whose long sides are linear and whose short sides are curved in a semicircular manner are fitted in notches provided in fins,
 wherein a surface of at least either one of each of the flat tubes and each of the fins has
 a plurality of concavities and convexities in which a difference in height between one of peak portions that has a smallest height and one of trough portions that has a smallest depth is 10 μm or larger, and 
   a foreign substance having a higher melting point than a flux used for surfaces of the flat tubes and the fins is added to the flux in advance.   
     
     
         8 . The plate fin-tube heat exchanger of  claim 7 ,
 wherein the concavities and convexities are formed such that
 an angle formed between the surface of at least either one of each of the flat tubes and each of the fins and a line is 60 degrees or smaller, the line being tangent to an end of a portion of a dewdrop being present in contact with the surface of at least either one of each of the flat tubes and each of the fins. 
   
     
     
         9 . The plate fin-tube heat exchanger of  claim 7 ,
 wherein the concavities and convexities are
 provided in an oxide film that is formed by heat generated when the flat tubes and the fins are welded to each other. 
   
     
     
         10 . A refrigeration-and-air-conditioning system,
 wherein the plate fin-tube heat exchanger of  claim 7  is used as an evaporator.