Heat exchanger tube configuration for improved flow distribution

Abstract

A microchannel heat exchanger includes for each channel, a serpentine shaped tube for providing a plurality of parallel flow passes for successively conducting fluid flow therethrough, and being fluidly interconnected between an inlet and an outlet manifold. Multiple circuits are obtained by the individual serpentine shaped tubes. Various methods are provided for forming the serpentine shaped tubes.

1 . A heat exchanger of the type having at least one unit having inlet and outlet manifolds fluidly interconnected by a plurality of circuits with each circuit having separate parallel mini-channels for conducting the flow of refrigerant therebetween; wherein said parallel mini-channels are each formed in a serpentine shape so as to provide a plurality of parallel flow passes for successively conducting fluid flow therethrough and with each circuit having an inlet end fluidly connected to the inlet manifold and an outlet end fluidly connected to the outlet manifold and with each circuit having all of its parallel flow passes grouped together, and with each group being laterally spaced from all of the groups of the adjacent circuits. 
     
     
         2 . A heat exchanger as set forth in  claim 1  wherein said parallel mini-channels are each formed of a unitary member which is bent into the desired serpentine shape. 
     
     
         3 . A heat exchanger as set forth in  claim 1  wherein said parallel mini-channels are formed from a plurality of planar tubes with U-shaped members interconnected at the ends of adjacent planar tubes to provide the serpentine shape. 
     
     
         4 . A heat exchanger as set forth in  claim 1  wherein said parallel mini-channels are formed, in part, by fluidly interconnected J-shaped members. 
     
     
         5 . A heat exchanger as set forth in  claim 1  wherein said plurality of parallel flow passes have cross sectional areas which increase or decrease toward the downstream passes. 
     
     
         6 . A heat exchanger as set forth in  claim 5  wherein said increases or decreases are in a step wise fashion. 
     
     
         7 . A heat exchanger as set forth in  claim 1  wherein said inlet manifold includes a distributor disposed therein to facilitate the uniform distribution of refrigerant to the individual mini-channels. 
     
     
         8 . A heat exchanger as set forth in  claim 1  wherein said parallel mini-channels have their respective inlet ends oriented vertically. 
     
     
         9 . A heat exchanger as set forth in  claim 1  including a pair of units arranged in spaced relationship in the direction of airflow therethrough and with the respective directions of refrigerant flow being in counterflow relationship. 
     
     
         10 . A method of promoting uniform refrigerant flow from an inlet manifold of a heat exchanger to a plurality of parallel multi-channel, mini-channels fluidly connected thereto, comprising the steps of:
 providing a plurality of tubes shaped in a serpentine manner and arranged to form a plurality of circuits with each circuit having a plurality of parallel flow passes for successively conducting fluid flow therethrough and with each circuit having all of its parallel flow passes grouped together, and with each group being laterally spaced from all of the groups of the adjacent circuits; and   fluidly connected each circuit at one end thereof to an inlet manifold and at the other end thereof to an outlet manifold.   
     
     
         11 . A method as set forth in  claim 10  wherein said at least one flat tube is formed of a unitary member which is bent into the desired serpentine shape. 
     
     
         12 . A method as set forth in  claim 10  wherein said at least one flat tube is formed from a plurality of planar tubes with U-shaped members being interconnected at the ends of adjacent planar tubes to provide the serpentine shape. 
     
     
         13 . A method as set forth in  claim 10  wherein said parallel mini-channels are formed, in part, by fluidly interconnecting J-shaped members. 
     
     
         14 . A method as set forth in  claim 10  wherein said plurality of parallel flow passes have cross sectional areas which increase or decrease toward the downstream passes. 
     
     
         15 . A method as set forth in  claim 14  wherein said increases or decreases are in a step wise fashion. 
     
     
         16 . A method as set forth in  claim 10  wherein said inlet manifold includes a distributor disposed therein to facilitate the uniform distribution of refrigerant to the individual mini-channels. 
     
     
         17 . A method as set forth in  claim 10  and including the step of orienting the inlet ends of said plurality of flat tubes vertically with respect to one another. 
     
     
         18 . A method as set forth in  claim 10  and including the steps of providing another such heat exchanger in spaced relationship in the direction of air flow to said one heat exchanger and causing the respective directions of refrigerant flow through the heat exchangers to be in counterflow relationship.