Evaporatively cooled heat exchanger

Abstract

An heat exchanger assembly includes a plurality of tubes defining a plurality of parallel refrigerant passages therein carrying a refrigerant longitudinally from an inlet header to an outlet header. Water flows from a reservoir through a distributor apparatus to provide even wetting between the ends of the tubes as the water flows laterally over the tubes between an entry edge and an exit edge. A screen is provided adjacent the exit edge to collect excess water to be deposited into a water tray provided beneath and spaced from the exit edge of the tubes. A pump is provided to move water from the water tray to the reservoir to preserve water. If excess water is lost, such as through evaporation, a supplemental water feed line provides supplemental water to the system.

1 . A heat exchanger assembly comprising;
 a plurality of tubes extending longitudinally between an inlet end and an outlet end for carrying a refrigerant between said ends,   each of said tubes having a cross section including a pair of sides extending laterally between an entry edge and an exit edge,   an inlet header in fluid communication with said inlet end of said tubes for supplying refrigerant to said passages in said tubes,   an outlet header in fluid communication with said outlet end of said tubes for receiving the refrigerant from said passages in said tubes,   a watering system for providing a supply of water to wet each of said tubes,   said watering system including a reservoir for storing the supply of water, and   said watering system including a distributor apparatus for distributing water between said ends of said tubes to flow laterally across said tubes from said entry edge to said exit edge.   
   
   
       2 . A heat exchanger assembly as set forth in  claim 1  wherein said distributor apparatus includes a plurality of manifolds with each manifold extending along a different one of said entry edges of said tubes for distributing water at said entry edges. 
   
   
       3 . A heat exchanger assembly as set forth in  claim 2  wherein said watering system includes a plurality of branches in fluid communication with said reservoir and said manifolds with each branch supplying water to a different one of said manifolds. 
   
   
       4 . A heat exchanger assembly as set forth in  claim 3  wherein said headers extend vertically between a bottom and a top and said tubes extend horizontally between said headers with said sides of adjacent tubes facing one another and vertically spaced from one another between a bottom tube extending adjacent said bottoms of said headers and a top tube extending adjacent said tops of said headers. 
   
   
       5 . A heat exchanger assembly as set forth in  claim 4  wherein said sides of said tubes slope downwardly from said entry edge to said exit edge. 
   
   
       6 . A heat exchanger assembly as set forth in  claim 5  wherein each of said sides of said tubes slope at the same angle to extend parallel with each other. 
   
   
       7 . A heat exchanger assembly as set forth in  claim 5  wherein said sides of said bottom tube slope at a first angle and said sides of said top tube slope at a last angle different from said first angle and each tube between said bottom tube and said top tube slopes at progressively increasing angles from said first angle to said last angle. 
   
   
       8 . A heat exchanger assembly as set forth in  claim 4  wherein said bottom tube has a first distance between said entry edge and said exit edge and said top tube has a last distance between said entry edge and said exit edge and wherein said last distance is greater than said first distance and wherein each of said tubes between said bottom and top tubes have a progressively increasing distance between said entry edge and said exit edge from said first distance and less than said last distance. 
   
   
       9 . A heat exchanger assembly as set forth in  claim 4  including a water tray spaced from said exit edges of said tubes for receiving excess water exiting from each tube. 
   
   
       10 . A heat exchanger assembly as set forth in  claim 9  further comprising a screen positioned adjacent said exit edge of said tubes for collecting excess water flowing from each tube and for delivering the excess water into said water tray. 
   
   
       11 . A heat exchanger assembly as set forth in  claim 9  including a pump for moving water from said water tray to said reservoir. 
   
   
       12 . A heat exchanger assembly as set forth in  claim 11  including an electronic control in communication with said pump and said water tray for activating said pump in response to the volume of water in said water tray. 
   
   
       13 . A heat exchanger assembly as set forth in  claim 12  wherein said electronic control includes a high level water tray sensor for activating said pump in response to a high level of water in said water tray. 
   
   
       14 . A heat exchanger assembly as set forth in  claim 13  including a supplemental water feed line for selectively supplying water from a supplemental source to said water tray and a supplemental valve in said supplemental water feed line in communication with said electronic control and said electronic control including a low level water tray sensor and a low level reservoir sensor for activating said supplemental valve in response to a low level of water in said water tray and in said reservoir. 
   
   
       15 . A heat exchanger assembly as set forth in  claim 13  including a supplemental water feed line for selectively supplying water from a supplemental source to said reservoir and a supplemental valve in said supplemental water feed line in communication with said electronic control and said electronic control including a low level reservoir sensor for activating said supplemental valve in response to a low level of water in said reservoir. 
   
   
       16 . A heat exchanger assembly as set forth in  claim 12  further comprising a water metering system for distributing a specified flow rate of water from said reservoir to said sides of said tubes. 
   
   
       17 . A heat exchanger assembly as set forth in  claim 16  wherein said water metering system includes a wicking material for drawing water by capillary action from said reservoir to said manifolds. 
   
   
       18 . A heat exchanger assembly as set forth in  claim 16  wherein said water metering system includes a metering valve between said reservoir and said branches for adjustably controlling the flow rate of water from said reservoir to said tubes. 
   
   
       19 . A heat exchanger assembly as set forth in  claim 18  wherein said metering valve comprises a solenoid valve in communication with said electronic control. 
   
   
       20 . A heat exchanger assembly as set forth in  claim 19  wherein said electronic control includes a high level reservoir sensor for activating said solenoid valve in response to a high level of water in said reservoir. 
   
   
       21 . A heat exchanger assembly as set forth in  claim 4  wherein said sides of said tubes have a profile having a flat shape between said ends. 
   
   
       22 . A heat exchanger assembly as set forth in  claim 4  wherein said sides of said tubes have a profile having an arced shape between said ends. 
   
   
       23 . A heat exchanger assembly as set forth in  claim 4  wherein said sides of said tubes have a profile having a ridged semi-circular shape extending between said entry and exit edges. 
   
   
       24 . A heat exchanger assembly as set forth in  claim 4  including a wicking coating extending along said sides of said tubes for wicking water uniformly over said sides of said tubes. 
   
   
       25 . A heat exchanger assembly as set forth in  claim 4  further comprising a blower for moving air over said sides of said tubes. 
   
   
       26 . A heat exchanger assembly as set forth in  claim 25  further comprising said entry edge of said tubes disposed immediately downstream of said blower and said exit edge of said tubes disposed remotely downstream from said blower. 
   
   
       27 . A heat exchanger assembly comprising;
 a plurality of tubes extending longitudinally between an inlet end and an outlet end for carrying a refrigerant longitudinally between said ends,   each of said tubes having a cross section including a pair of sides extending laterally between an entry edge and an exit edge and including dividers extending longitudinally between said ends and between said sides to define a plurality of parallel refrigerant passages,   an inlet header in fluid communication with said inlet end of said tubes for supplying the refrigerant to said passages in said tubes,   an outlet header in fluid communication with said outlet end of said tubes for receiving the refrigerant from said passages in said tubes,   said headers extending vertically between a bottom and a top and said tubes extending horizontally between said headers with said sides of adjacent tubes facing one another and vertically spaced from one another between a bottom tube extending adjacent said bottoms of said headers and a top tube extending adjacent said tops of said headers,   a blower for moving air over said sides of said tubes,   said entry edge of said tubes disposed immediately downstream of said blower and said exit edge of said tubes disposed remotely downstream from said blower,   a watering system for providing a supply of water to wet each of said tubes,   said watering system including a reservoir for storing the supply of water,   a wicking coating extending along said sides of said tubes for wicking water uniformly over said sides of said tubes,   said watering system including a distributor apparatus for distributing water between said ends of said tubes to flow laterally across said tubes from said entry edge to said exit edge,   said distributor apparatus including a plurality of manifolds extending along said entry edges of each tube in fluid communication with said reservoir,   said watering system including a pipe in fluid communication with said reservoir and a plurality of branches in fluid communication with said pipe with each branch supplying water to said entry edge of a different one of said tubes,   a screen positioned adjacent said exit edge of said tubes for collecting excess water flowing from each tube,   a water tray positioned below said screen and spaced from said exit edge of said tubes for receiving the excess water therefrom,   a pump for moving water from said water tray to said reservoir,   an electronic control in communication with said pump and said water tray for activating said pump in response to the volume of water in said water tray, and   a water metering system for distributing a specified flow rate of water from said reservoir to said sides of said tubes.