Plate heat exchanger assembly with enhanced heat transfer characteristics

Abstract

A plate heat exchanger for accommodating a circulating refrigerant and heat transfer fluid. The plate heat exchanger includes a plurality of heat transfer plates and at least one electrode plate. The plurality of heat transfer plates are mounted in parallel relationship to each other defining alternating flow spaces for a refrigerant and a heat transfer fluid. The electrode plate is located in each refrigerant flow space and is spaced from the adjacent heat transfer plates. The electrode plate includes outer electrode surfaces on each side thereof to produce an electric field. The effect of the electric field is an increase in the heat transfer rate between the refrigerant and heat transfer fluid. The invention also includes a method of exchanging heat between a heat transfer fluid and a refrigerant in a plate heat exchanger.

What is claimed is:  
     
         1 . A plate heat exchanger for accommodating two circulating heat exchange mediums, comprising: 
 a plurality of heat transfer plates mounted in parallel relationship to each other defining alternating fluid channels comprising first and second fluid channels, the first fluid channel for containing a first heat exchange medium, the second fluid channel for containing a second heat exchange medium; and    an electrode plate located in each first fluid channel and positioned generally parallel to and spaced from the heat transfer plates, the electrode plate including outer electrode surfaces on each side thereof to produce an electric field,    wherein either the outer electrode surfaces of each electrode plate, or the surfaces of the heat transfer plates surrounding each electrode plate and defining the first fluid channel, include surface irregularities, and wherein the effect of the electric field on the surface irregularities is an increase in the heat transfer rate between the first heat exchange medium and the second heat exchange medium.    
     
     
         2 . The plate heat exchanger of  claim 1 , further comprising insulators for electrically insulating the electrode plate from the surrounding heat transfer plates, said insulators supporting the electrode plate in its respective first fluid channel.  
     
     
         3 . The plate heat exchanger of  claim 2 , wherein said insulators contact the heat transfer plates that surround the electrode plate.  
     
     
         4 . The plate heat exchanger of  claim 3 , wherein said dimples are formed on the surfaces of the heat transfer plates and said insulators are fit with said dimples.  
     
     
         5 . The plate heat exchanger of  claim 2 , wherein said electrode plate includes a plurality of holes for the insulators to pass through.  
     
     
         6 . The plate heat exchanger of  claim 5 , wherein dimples are formed on the surfaces of the heat transfer plates and said electrode plate includes a plurality of holes for accepting said dimples.  
     
     
         7 . The plate heat exchanger of  claim 6 , wherein said dimples for contacting the insulators and said dimples accepted by the electrode holes are stamped onto the heat transfer plates.  
     
     
         8 . The plate heat exchanger of  claim 1 , wherein each electrode plate is positioned substantially equidistant from the two adjacent heat transfer plates that define the first fluid channel.  
     
     
         9 . The plate heat exchanger of  claim 1 , wherein each heat transfer plate defines apertures for entry and exit of each of the first and second heat exchange mediums.  
     
     
         10 . The plate heat exchanger of  claim 9 , further comprising an electrical connector for imparting electrical voltage on the electrode plates, the electrode plates being electrically connected to one another by the electrical connector.  
     
     
         11 . The plate heat exchanger of  claim 10 , wherein the electrical connector comprises one of a rod, wire, and threaded rod passing through one of the apertures for entry and exit of the refrigerant.  
     
     
         12 . The plate heat exchanger of  claim 11 , wherein each electrode plate includes a projection through which the electrical connector may pass to provide said electrical connection between the electrode plates.  
     
     
         13 . The plate heat exchanger of  claim 12 , wherein the electrical connector is compression fit inside an opening in the electrode plate projection.  
     
     
         14 . The plate heat exchanger of  claim 1 , wherein the heat transfer plate surfaces surrounding each electrode plate and defining the first fluid channels include surface irregularities, and the plate heat exchanger comprises an evaporator.  
     
     
         15 . The plate heat exchanger of  claim 14 , wherein the outer electrode surfaces are substantially smooth.  
     
     
         16 . The plate heat exchanger of  claim 14 , wherein the surface irregularities include one of cross-groove microfins, porous coatings, scratched surfaces, sintered surfaces, abraided surfaces, and dimpled surfaces.  
     
     
         17 . The plate heat exchanger of  claim 1 , wherein the outer electrode surfaces of each electrode plate include surface irregularities, and the plate heat exchanger comprises a condenser.  
     
     
         18 . The plate heat exchanger of  claim 17 , wherein the heat transfer plate surfaces surrounding each electrode plate and defining the first fluid channels are substantially smooth.  
     
     
         19 . The plate heat exchanger of  claim 17 , wherein the electrode plate is a wire mesh.  
     
     
         20 . The plate heat exchanger of  claim 1 , wherein said first heat exchange medium in the first fluid channel comprises a refrigerant, and said second heat exchange medium in the second fluid channel comprises a heat transfer fluid.  
     
     
         21 . A plate heat exchanger for accommodating a circulating refrigerant and heat transfer fluid, comprising: 
 a plurality of heat transfer plates mounted in parallel relationship to each other defining alternating flow spaces for a refrigerant and a heat transfer fluid; and    an electrode plate located in each refrigerant flow space and spaced from the adjacent heat transfer plates, the electrode plate including outer electrode surfaces on each side thereof to produce an electric field,    wherein the effect of the electric field is an increase in the heat transfer rate between the refrigerant and heat transfer fluid.    
     
     
         22 . The plate heat exchanger of  claim 21 , wherein either the surfaces of the heat transfer plates defining the refrigerant flow space or the outer electrode surfaces of the electrode plates include surface irregularities.  
     
     
         23 . The plate heat exchanger of  claim 22  wherein the surface irregularities include one of cross-groove microfins, porous coatings, scratched surfaces, sintered surfaces, abraided surfaces, and dimpled surfaces.  
     
     
         24 . The plate heat exchanger of  claim 21 , wherein the electrode plate is substantially flat-shaped and is substantially parallel to the heat transfer plates.  
     
     
         25 . The plate heat exchanger of  claim 21 , wherein the electrode plate is positioned substantially equidistant from the adjacent heat transfer plates in the refrigerant flow space.  
     
     
         26 . The plate heat exchanger of  claim 22 , wherein the surfaces of the heat transfer plates defining the refrigerant flow space include the surface irregularities, and the application of said electric field presses the refrigerant against the surface irregularities.  
     
     
         27 . The plate heat exchanger of  claim 22 , wherein the outer electrode surfaces of the electrode plates include the surface irregularities, and the application of said electric field pulls the refrigerant away from the surfaces of the heat transfer plates defining the refrigerant flow space.  
     
     
         28 . A heat exchanger assembly for use in an HVAC system, comprising: 
 a stacked array of heat transfer plates mounted in parallel relationship to each other to define a plurality of first flow spaces for a first heat exchange medium and a plurality of second flow spaces for a second heat exchange medium;    a plurality of electrode plates, an electrode plate being positioned in each of the first flow spaces, the electrode plates having electrode surfaces to produce an electric field,    wherein the effect of the electric field is an increase in the heat transfer rate between the first heat exchange medium and the second heat exchange medium.    
     
     
         29 . The heat exchanger assembly of  claim 28 , wherein each heat transfer plate includes a first heat exchange medium flow surface defining the first flow space, either the first surface of each heat transfer plate or the outer surfaces of the electrode plates including surface irregularities.  
     
     
         30 . The heat exchanger assembly of  claim 29 , wherein the first heat exchange medium flow surface of each heat transfer plate includes surface irregularities, and the plate heat exchanger comprises an evaporator.  
     
     
         31 . The heat exchanger assembly of  claim 29 , wherein the outer surfaces of each electrode plate include surface irregularities, and the plate heat exchanger comprises a condenser.  
     
     
         32 . The heat exchanger assembly of  claim 29 , wherein the electrode plate is positioned substantially equidistant from the adjacent heat transfer plates in the refrigerant flow space.  
     
     
         33 . A method of exchanging heat between a heat transfer fluid and a refrigerant in a plate heat exchanger, comprising the steps of: 
 providing a plurality of parallel heat transfer plates;    providing an electrode plate inside each of a plurality of first flow spaces defined by first surfaces of adjacent heat transfer plates;    flowing the refrigerant through the plurality of first flow spaces;    flowing the heat transfer fluid along a second surface of each of the heat transfer plates, said second surfaces of adjacent heat transfer plates defining a second flow space for the heat transfer fluid; and    applying a voltage to the electrode plates to create an electric field, said electric field increasing the heat transfer rate between the refrigerant and the heat transfer fluid.    
     
     
         34 . The method of  claim 33 , wherein said step of applying a voltage to the electrode plates includes attaching an electrical connector to each of the electrode plates to supply the voltage to the plurality of electrode plates.  
     
     
         35 . The method of  claim 33 , wherein the step of providing electrode plates includes forming surface irregularities on the first surfaces of the heat transfer plates.  
     
     
         36 . The method of  claim 33 , wherein the step of providing electrode plates includes forming surface irregularities on the outer surfaces of the electrode plates.  
     
     
         37 . The method of  claim 33 , further comprising the step of electrically insulating the electrode plate from the adjacent heat transfer plates.  
     
     
         38 . The method of  claim 33 , wherein the electrode plate is positioned substantially equidistant from the adjacent heat transfer plates.  
     
     
         39 . The method of  claim 33 , wherein the step of applying a voltage to the electrode plates includes applying a voltage between 5 to 30 kV.  
     
     
         40 . The method of  claim 39 , wherein the applied voltage is approximately 20 kV.  
     
     
         41 . A plate heat exchanger for accommodating a circulating refrigerant and heat transfer fluid, comprising: 
 opposing plates with sets of aligned outwardly and inwardly extending dimples, the first set of aligned dimples extending inwardly towards each other, the second set of aligned dimples extending outwardly away from each other to create an open space;    an electrode plate positioned between the opposing plates, the electrode plate having holes aligned with the dimples; and    an insulator in the open space to hold and be positioned in the outwardly extending dimples and to pass through an aligned hole of the electrode plate,    wherein said inwardly extending dimples pass through an aligned hole of the electrode plate and touch each other.