Dual mode heat exchanger assembly

Abstract

A dual mode heat exchanger has a first and second manifold with a plurality of flow tubes fluidly connecting the manifolds for passing refrigerant between the manifolds. The first manifold is divided into at least two chambers. The second manifold defines a single cavity but can form more than one chamber. Separators divide the cavities and are offset from each other creating groups of flow tubes that connect one chamber in each manifold. At least one port in each chamber of one of the manifolds is in the open position for controlling refrigerant circulation. All of the ports are opened in one of the manifolds to permit refrigerant to pass through all of the plurality of tubes in at least one pass in evaporator mode. At least one of the ports is closed to permit refrigerant to pass through all of the plurality of flow tubes in at least two passes in condenser mode.

1 . A heat exchanger assembly comprising:
 a first manifold and a second manifold each defining a hollow cavity and in spaced and substantially parallel relationship with each other;   a plurality of flow tubes extending between and fluidly connecting said first and second manifolds for passing refrigerant between said manifolds;   a separator disposed within said first manifold and dividing said cavity into a first chamber and a second chamber;   a plurality of ports fluidly connected at least one of said first and second manifolds with each of said ports having an open position for allowing refrigerant to flow into and out of said manifolds and a closed position for preventing refrigerant from flowing into and out of said manifolds with said plurality of ports including at least a first port, a second port, and a third port;   an external controller for switching between an evaporator mode and a condenser mode; and   one of said ports in each chamber and cavity of one of said manifolds being in said open position for circulating refrigerant through all of said plurality of flow tubes in at least one pass when in said evaporator mode and at least one of said ports being in said closed position for circulating refrigerant through said plurality of flow tubes in at least two passes when in said condenser mode.   
   
   
       2 . An assembly as set forth in  claim 1  wherein said first port is connected to said first chamber said second port is connected to said second chamber and said third port is connected to said cavity of said second manifold. 
   
   
       3 . An assembly as set forth in  claim 2  wherein said evaporator mode is further defined by at least one of said ports in each chamber of said first manifold and at least one of said ports in said cavity of said second manifold being in said open position for circulating refrigerant in one pass. 
   
   
       4 . An assembly as set forth in  claim 2  wherein said condenser mode is further defined by said first port and said second port being in said open position and said third port being in said closed position for circulating refrigerant in two passes. 
   
   
       5 . An assembly as set forth in  claim 2  wherein said separator is further defined as a first separator and further including a second separator disposed within said cavity of said second manifold dividing said cavity of said second manifold into a third chamber and a fourth chamber. 
   
   
       6 . An assembly as set forth in  claim 5  wherein said second separator is offset from said first separator with said first chamber fluidly connected to said third chamber through a first group of said flow tubes, said second chamber fluidly connected to said third chamber by a second group of said flow tubes, and said second chamber fluidly connected to said fourth chamber by a third group of said flow tubes. 
   
   
       7 . An assembly as set forth in  claim 5  further including a fourth port connected to said fourth chamber with said first, second, third, and fourth ports being in said open position when in said evaporator mode for circulating refrigerant in one pass. 
   
   
       8 . An assembly as set forth in  claim 7  wherein said condenser mode is further defined by said first port and said fourth port being in said open position and said second port and said third port being in said closed position for circulating refrigerant in three passes. 
   
   
       9 . An assembly as set forth in  claim 2  wherein said separator is further defined as a first separator and further including a second and a third separator disposed within said second manifold dividing said cavity into a third, fourth and fifth chamber. 
   
   
       10 . An assembly as set forth in  claim 9  wherein both of said second and third separators are offset from said first separator with said first chamber fluidly connected to said third chamber by a first group of said flow tubes, said first chamber fluidly connected to said fourth chamber by a second group of said flow tubes, said second chamber fluidly connected to said fourth chamber by a third group of said flow tubes, and said second chamber fluidly connected to said fifth chamber by a fourth group of said flow tubes. 
   
   
       11 . An assembly as set forth in  claim 9  further including a fourth port connected to said fourth chamber and a fifth port connected to said fifth chamber with said first, second, third, fourth, and fifth ports being in said open position when in said evaporator mode for circulating refrigerant in one pass. 
   
   
       12 . An assembly as set forth in  claim 11  wherein said condenser mode is further defined by said first port said second port and said fourth port being in said closed position and said third port and said fifth port being in said open position for circulating refrigerant in four passes. 
   
   
       13 . An assembly as set forth in  claim 1  wherein said separator is further defined as a first separator and further including a second separator and a third separator disposed within said second manifold dividing said cavity into a third, fourth and fifth chamber. 
   
   
       14 . An assembly as set forth in  claim 13  wherein both of said second and said third separators are offset from said first separator with said first chamber fluidly connected to said third chamber by a first group of said flow tubes, said first chamber fluidly connected to said fourth chamber by a second group of said flow tubes, said second chamber fluidly connected to said fourth chamber by a third group of said flow tubes, and said second chamber fluidly connected to said fifth chamber by a fourth group of said flow tubes. 
   
   
       15 . An assembly as set forth in  claim 13  further including a third port connected to said third chamber and a fourth port connected to said fourth chamber and a fifth port connected to said fifth chamber and with said third, fourth and fifth ports being in said open position when in said evaporator mode for circulating refrigerant in two passes. 
   
   
       16 . An assembly as set forth in  claim 15  wherein said condenser mode is further defined by said fourth port being in said closed position and said third port and said fifth port being in said open position for circulating refrigerant in four passes. 
   
   
       17 . An assembly as set forth in  claim 1  including a distribution tube disposed within one of said chambers and said cavity with said distribution tube having a plurality of apertures and with said distribution tube being fluidly connected to one of said plurality of ports for passing refrigerant from one of said plurality of ports into at least one of said chambers and said cavity and further defining an evaporator mode inlet chamber. 
   
   
       18 . An assembly as set forth in  claim 17  including a fourth port fluidly connected to said evaporator mode inlet chamber for circulating the refrigerant in said condenser mode. 
   
   
       19 . A method of operating a heat exchanger having a first manifold divided into a first chamber and a second chamber with a first port and second port, a second manifold defining at least one chamber with a third port, and a plurality of flow tubes fluidly connecting the manifolds, said method comprising the steps of:
 opening one of said ports in each chamber of said manifolds to define an evaporator mode;   introducing refrigerant into one of the manifolds defining an inlet chamber;   passing the refrigerant through all of the plurality of flow tubes in a single pass;   exiting the refrigerant from an opposing manifold;   closing the third port of the second manifold to define a condenser mode;   introducing the refrigerant into one of the chambers of one of the manifolds to define an inlet chamber;   passing the refrigerant through the plurality of flow tubes connected to the inlet chamber;   passing the refrigerant into another chamber of one of the manifolds to define a mid-flow chamber;   passing the refrigerant through the plurality of flow tubes connected to the mid-flow chamber;   passing the refrigerant into another chamber of one of the manifolds to define an outlet chamber; and   exiting the refrigerant through the port connected to the outlet chamber.   
   
   
       20 . A method of operating a heat exchanger having a first manifold divided into a first chamber and a second chamber and a second manifold divided onto a third chamber, a fourth chamber and a fifth chamber, with a third port, a fourth port, a fifth port and a plurality of flow tubes fluidly connecting the manifolds, said method comprising the steps of:
 opening at least one of the ports to define an evaporator mode;   introducing the refrigerant into one of the manifolds to define an inlet chamber;   passing the refrigerant through the plurality of flow tubes connected to the inlet chamber;   passing the refrigerant into the opposing manifold to define a mid-flow chamber;   passing the refrigerant through the plurality of flow tubes connected to the mid-flow chamber;   passing the refrigerant into the opposing manifold to define an outlet chamber;   exiting the refrigerant through the port connected to the outlet chamber;   closing the fourth port and opening the third and fifth ports to define a condenser mode;   introducing the refrigerant into the third port of the second manifold to define an inlet chamber;   passing the refrigerant through the plurality of flow tubes connected to the inlet chamber;   passing the refrigerant into the first chamber of the first manifold to define a first mid-flow chamber;   passing the refrigerant through the plurality of flow tubes connected to the first mid-flow chamber;   passing the refrigerant into the fourth chamber of the second manifold to define a second mid-flow chamber;   passing the refrigerant through the plurality of flow tubes connected to the second mid-flow chamber;   passing the refrigerant into the second chamber of the first manifold to define a third mid-flow chamber;   passing the refrigerant through the plurality of flow tubes connected to the third mid-flow chamber;   passing the refrigerant into the fifth chamber of the second manifold to define an outlet chamber; and   exiting the refrigerant through the fifth port connected to the outlet chamber.