Abstract:
A heat exchanger for a vehicle is shown, wherein the heat exchanger includes a plurality of tubes having integrated thermoelectric devices disposed thereon to facilitate heat transfer between the tubes and an atmosphere surrounding the tubes.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. application Ser. No. 11/497,695, filed Aug. 2, 2006, titled HEAT EXCHANGER TUBE HAVING INTEGRATED THERMOELECTRIC DEVICES, the entire contents of which are incorporated by reference herein and made a part of this specification. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    The present invention relates to a heat exchanger tube and more particularly to a heat exchanger tube having integrated thermoelectric devices to increase a thermal efficiency of the heat exchanger. 
         [0004]    2. Description of Related Art 
         [0005]    An air-cooled fin-type heat exchanger is very well known. Heat exchangers are used for changing the temperature of various working fluids, such as an engine coolant, an engine lubricating oil, an air conditioning refrigerant, and an automatic transmission fluid, for example. The heat exchanger typically includes a plurality of spaced apart fluid conduits or tubes connected between an inlet tank and an outlet tank, and a plurality of heat exchanging fins disposed between adjacent conduits. Air is directed across the fins of the heat exchanger by a cooling fan or a motion of a vehicle, for example. As the air flows across the fins, heat in a fluid flowing through the tubes is conducted through the walls of the tubes, into the fins, and transferred into the air. 
         [0006]    One of the primary goals in heat exchanger design is to achieve the highest possible thermal efficiency. Thermal efficiency is measured by dividing the amount of heat that is transferred by the heat exchanger under a given set of conditions (amount of airflow, temperature difference between the air and fluid, and the like) by the theoretical maximum possible heat transfer under those conditions. Thus, an increase in the rate of heat transfer under a given set of conditions results in a higher thermal efficiency. 
         [0007]    Typically, to improve thermal efficiency, the airflow must be improved and/or a pressure drop through the heat exchanger must be reduced. Improved heat exchanger performance can be accomplished by forming the fins and/or louvers on the fins at a predetermined angle in a manner also well known in the art. Pressure drop is associated with the change in airflow direction caused by the louvered fins. A higher air pressure drop can result in a lower heat transfer rate. Various types of fin and louver designs have been disclosed in the prior art with the object of increasing the heat exchanger efficiency by making improvements in the fins, louvers, and airflow pattern. 
         [0008]    Examples of these prior art fin and louver designs include an addition of fin rows in order to increase the amount of air encountered by the heat exchanger. Other designs include louvers formed at an angle to the fin wall, rather than square to the fin wall. Further, the prior art discloses heat exchangers with multiple changes of airflow direction. Air flows through the louvers until a middle transition piece or turnaround rib is reached. The air then changes direction and flows through exit louvers to exit the heat exchanger. Fin design continues to play an important role in increasing heat exchanger efficiency. 
         [0009]    A thermoelectric device can be used to transfer heat between fluids, such as from air flow to a fluid in a fluid conduit, for example. The thermoelectric device includes a hot side and a cold side, wherein one of the hot side and the cold side is in communication with each of the fluids. A heat transfer efficiency of the thermoelectric device decreases as a difference in temperature between the hot side and the cold side thereof increases. 
         [0010]    It would be desirable to produce a tube for a heat exchanger having an integrated thermoelectric device whereby a thermal efficiency of the heat exchanger is maximized. 
       SUMMARY 
       [0011]    Harmonious with the present invention, a tube for a heat exchanger having an integrated thermoelectric device whereby a thermal efficiency of the heat exchanger is maximized has surprisingly been discovered. 
         [0012]    In one embodiment, a tube for a heat exchanger comprises a hollow conduit having a wall, a first end, and a spaced apart second end; and a thermoelectric device in thermal communication with the wall of the conduit to facilitate heat transfer between a first fluid in the conduit and a second fluid outside of the conduit. 
         [0013]    In another embodiment, a heat exchanger comprises at least one heat exchanger tank; a hollow tube having a wall, a first end, and a spaced apart second end, the tube in fluid communication with the at least one heat exchanger tank; a thermoelectric device in thermal communication with the wall of the tube; and a heat exchanger fin in thermal communication with the thermoelectric device. 
         [0014]    In another embodiment, a heat exchanger comprises at least one heat exchanger tank; a plurality of hollow tubes, each tube having a wall, a first end, and a spaced apart second end, the tubes in fluid communication with the at least one heat exchanger tank and adapted to convey a first fluid; a plurality of heat exchanger fins disposed adjacent the tubes and in thermal communication with a second fluid; and a plurality of thermoelectric devices, at least one thermoelectric device disposed between the tubes and the fins to facilitate heat transfer therebetween. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The above, as well as other objects and advantages of the invention, will become readily apparent to those skilled in the art from reading the following detailed description of a preferred embodiment of the invention when considered in the light of the accompanying drawings in which: 
           [0016]      FIG. 1  is an end sectional view of a tube for a heat exchanger in accordance with an embodiment of the invention; 
           [0017]      FIG. 2  is an end sectional view a heat exchanger using the tube of  FIG. 1 ; 
           [0018]      FIG. 3  is a side sectional view of a tube for a heat exchanger in accordance with another embodiment of the invention; and 
           [0019]      FIG. 4  is a front sectional view of a heat exchanger in accordance with another embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0020]    The following detailed description and appended drawings describe and illustrate various exemplary embodiments of the invention. The description and drawings serve to enable one skilled in the art to make and use the invention, and are not intended to limit the scope of the invention in any manner. 
         [0021]      FIG. 1  shows a cylindrical tube  10  for a heat exchanger  40  illustrated in  FIG. 2 . The tube  10  has an outer wall  12  with a substantially circular cross-sectional shape. Other cross-sectional shapes can be used as desired. The wall  12  is preferably formed from copper or steel; however, other materials may be used to form the wall  12  without departing from the scope and spirit of the invention. The wall  12  forms a hollow interior portion  14 . 
         [0022]    A thermoelectric device (TED)  16  surrounds and is in thermal communication with the wall  12 . The TED  16  includes a first heat transfer surface  18  and a second heat transfer surface  20 . The first heat transfer surface  18  is in thermal communication with the wall  12 . The second heat transfer surface  20  is in thermal communication with a plurality of fins  22  surrounding the TED  16 . 
         [0023]    The TED  16  is in electrical communication with a control system (not shown). The control system controls an electric current sent to the TED  16 . When a current is delivered in one direction, one of the first heat transfer surface  18  and the second heat transfer surface  20  generates thermal energy and the other of the first heat transfer surface  18  and the second heat transfer surface  20  absorbs thermal energy. When the current is reversed, the one of the first heat transfer surface  18  and the second heat transfer surface  20  which was generating thermal energy now absorbs thermal energy, and the other of the first heat transfer surface  18  and the second heat transfer surface  20  now generates thermal energy. When the current is increased, a heating and cooling capacity of the TED  16  is increased. Likewise, when the current is decreased, the heating and cooling capacity of the TED  16  is decreased. 
         [0024]    The TED  16  may be any conventional device such as: those produced by Marlow Industries, Inc. of Dallas, Tex.; the thermoelectric systems described in U.S. Pat. No. 6,539,725 to Bell; a quantum tunneling converter; a Peltier device; a thermo ionic module; a magneto caloric module; an acoustic heating mechanism; a solid state heat pumping device; and the like; for example; or any combination of the devices listed above. Although a single thermoelectric device is shown, it is understood that additional thermoelectric devices can be used, as desired. 
         [0025]    In use, a first fluid (not shown) is caused to flow through the hollow interior portion  14  of the tube  10 . The first fluid can be any conventional fluid such as air or a coolant such as a water-glycol coolant, for example. The first fluid contains thermal energy which is transferred to the wall  12 . Current is supplied to the TED  16 , which causes the first heat transfer surface  18  of the TED  16  to absorb thermal energy from the wall  12 . Simultaneously, the second heat transfer surface  20  of the TED  16  generates thermal energy. The thermal energy generated by the second heat transfer surface  20  of the TED  16  is transferred to the fins  22 . A second fluid (not shown) is caused to flow across and contact the fins  22 . The second fluid can be any conventional fluid such as air, for example. The thermal energy transferred from the second heat transfer surface  20  of the TED  16  to the fins  22  is transferred to the second fluid. 
         [0026]      FIG. 3  shows a tube  60  for a heat exchanger (not shown) having a first wall  62 , a second wall  64 , a fluid inlet  66 , and a fluid outlet  68 . The tube  60  shown is a flat tube for use in a flat tube heat exchanger. However, tubes having other shapes and for use in other types of heat exchangers, such as cross flow heat exchangers, shell and tube heat exchangers, or counter flow heat exchangers, for example, can be used as desired without departing from the scope and spirit of the invention. The walls  62 ,  64  are preferably formed from copper or steel. However, other materials may be used to form the walls  62 ,  64  as desired. The first wall  62 , the second wall  64 , and a pair of side walls (not shown) cooperate to form a hollow interior portion  70 . 
         [0027]    A first thermoelectric device (TED)  72  is disposed adjacent to and is in thermal communication with the first wall  62 . The first TED  72  includes a first heat transfer surface  74  and a second heat transfer surface  76 . The first heat transfer surface  74  is in thermal communication with the first wall  62 . The second heat transfer surface  76  is in thermal communication with a plurality of fins  78  disposed adjacent to the first TED  72 . 
         [0028]    A second thermoelectric device (TED)  80  is disposed adjacent to and is in thermal communication with the second wall  64 . The second TED  80  includes a first heat transfer surface  82  and a second heat transfer surface  84 . The first heat transfer surface  82  is in thermal communication with the second wall  64 . The second heat transfer surface  84  is in thermal communication with a plurality of fins  86  disposed adjacent to the second TED  80 . 
         [0029]    The TEDs  72 ,  80  may be any conventional devices such as: those produced by Marlow Industries, Inc. of Dallas, Tex.; the thermoelectric systems described in U.S. Pat. No. 6,539,725 to Bell; a quantum tunneling converter; a Peltier device; a thermo ionic module; a magneto caloric module; an acoustic heating mechanism; a solid state heat pumping device; and the like; for example; or any combination of the devices listed above. Although two thermoelectric devices are shown, it is understood that a single or additional thermoelectric devices can be used, as desired. Further, it is understood that the side walls of the tube  60  may include additional TEDs if desired. If the side walls of the tube include additional TEDs, a plurality of fins can be disposed adjacent the TEDs as desired. 
         [0030]    The first TED  72  and the second TED  80  are in electrical communication with a control system (not shown). The control system controls an electric current sent to the TEDs  72 ,  80 . When a current is delivered in one direction, one of the first heat transfer surfaces  74 ,  82  and the second heat transfer surfaces  76 ,  84  generates thermal energy and the other of the first heat transfer surfaces  74 ,  82  and the second heat transfer surfaces  76 ,  84  absorbs thermal energy. When the current is reversed, the one of the first heat transfer surfaces  74 ,  82  and the second heat transfer surfaces  76 ,  84  which was generating thermal energy now absorbs thermal energy, and the other of the first heat transfer surfaces  74 ,  82  and the second heat transfer surfaces  76 ,  84  now generates thermal energy. When the current is increased, a heating and cooling capacity of the TEDs  72 ,  80  is increased. Likewise, when the current is decreased, the heating and cooling capacity of the TEDs  72 ,  80  is decreased. 
         [0031]    In use, a first fluid (not shown) is caused to flow through the hollow interior portion  70  of the tube  60 . The first fluid can be any conventional fluid such as air or a coolant such as a water-glycol coolant, for example. The first fluid contains thermal energy which is transferred to the first wall  62  and the second wall  64 . Current is supplied to the TEDs  72 ,  80 , which causes the first heat transfer surfaces  74 ,  82  of the TEDs  72 ,  80  to absorb thermal energy from the first wall  62  and the second wall  64 . Simultaneously, the second heat transfer surfaces  76 ,  84  of the TEDs  72 ,  80  generate thermal energy. The thermal energy generated by the second heat transfer surfaces  76 ,  84  of the TEDs  72 ,  80  is transferred to the fins  78 ,  86 . A second fluid (not shown) is caused to flow across and contact the fins  78 ,  86 . The second fluid can be any conventional fluid such as air, for example. The thermal energy transferred from the second heat transfer surfaces  76 ,  84  of the TEDs  72 ,  80  to the fins  78 ,  86  is transferred to the second fluid. 
         [0032]      FIG. 4  shows a heat exchanger  100  in accordance with another embodiment of the invention. The heat exchanger  100  includes a first header  102  and a spaced apart second header  104 . A plurality of cylindrical tubes  106  are disposed between the first header  102  and the second header  104 . The tubes have walls  108  with a substantially circular cross-sectional shape. Other cross-sectional shapes can be used as desired. The walls  108  are preferably formed from copper or steel. However, other materials may be used to form the walls  108  without departing from the scope and spirit of the invention. The walls  108  form hollow interior portions  110  and include a fluid inlet  107  and a fluid outlet  109 . 
         [0033]    A thermoelectric device (TED)  112  surrounds and is in thermal communication with each of the walls  108 . Each TED  112  includes a first heat transfer surface  114  and a second heat transfer surface  116 . The first heat transfer surface  114  is in thermal communication with the wall  108  of the corresponding tube  106 . The second heat transfer surface  116  is in thermal communication with a plurality of fins  120  disposed between each adjacent tube  106 . 
         [0034]    Each TED  112  is in electrical communication with a control system (not shown). The control system controls an electric current sent to the TED  112 . When a current is delivered in one direction, one of the first heat transfer surface  114  and the second heat transfer surface  116  generates thermal energy and the other of the first heat transfer surface  114  and the second heat transfer surface  116  absorbs thermal energy. When the current is reversed, the one of the first heat transfer surface  114  and the second heat transfer surface  116  which was generating thermal energy now absorbs thermal energy and the other of the first heat transfer surface  114  and the second heat transfer surface  116  now generates thermal energy. Additionally, when the current is increased, a heating and cooling capacity of the TED  112  is increased. Likewise, when the current is decreased, the heating and cooling capacity of the TED  112  is decreased. 
         [0035]    The TEDs  112  may be any conventional devices such as: those produced by Marlow Industries, Inc. of Dallas, Tex.; the thermoelectric systems described in U.S. Pat. No. 6,539,725 to Bell; a quantum tunneling converter; a Peltier device; a thermo ionic module; a magneto caloric module; an acoustic heating mechanism; a solid state heat pumping device; and the like; for example; or any combination of the devices listed above. Although a single thermoelectric device is shown disposed adjacent each of the tubes  106 , it is understood that additional thermoelectric devices can be used, as desired. 
         [0036]    In use, a first fluid (not shown) is caused to flow from the second header  104  through the fluid inlets  107  into the hollow interior portions  110  of the tubes  106 . The first fluid can be any conventional fluid such as air or a coolant such as a water-glycol coolant, for example. The first fluid contains thermal energy which is transferred to the walls  108 . Current is supplied to each TED  112 , which causes the first heat transfer surface  114  of each TED  112  to absorb thermal energy from the wall  108  of the corresponding tube  106 . Simultaneously, the second heat transfer surface  116  of each TED  112  generates thermal energy. The thermal energy generated by the second heat transfer surface  116  of each TED  112  is transferred to the fins  120 . A second fluid (not shown) is caused to flow across and contact the fins  120 . The second fluid can be any conventional fluid such as air, for example. The thermal energy transferred from the second heat transfer surface  116  of each TED  112  to the fins  120  is transferred to the second fluid. The first fluid flows out of the fluid outlets  109  and into the first header  102 . 
         [0037]    From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications to the invention to adapt it to various usages and conditions.