Patent Publication Number: US-2009223648-A1

Title: Heat exchanger with variable heat transfer properties

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a heat exchanger, and more specifically to a heat exchanger with variable heat transfer properties. 
     2. Description of Related Art 
     Various kinds of heat exchangers have been proposed. One example is U.S. patent publication 20070039721 to Murray. The Murray patent describes a heat exchanger that electromagnetically actuates and controls heat transfer by using electromagnets. One of the heat exchange fluids is a slurry consisting of tiny, highly conductive particles made of metal or metal oxides. When a signal is transmitted to an electromagnet by an amplifier, a magnetic field is created near the conduit wall. The particles in the fluid are attracted to the conduit wall resulting in increased heat transfer from the conduit wall to the particles and ultimately to the fluid. 
     Some heat exchangers include features that assist in the heat transfer process. One example is U.S. Pat. No. 6,241,467 to Zelesky et al. that teaches a cooled stator vane in a gas turbine engine. The vane is cooled by flowing cooling air through a passage inside the vane. Part of the passage is provided with stationary chevron shaped trip strips that angle in the direction of flow. The trip strips are used to increase convective heat transfer by creating vortices in the flow. In another example, U.S. Pat. No. 2,930,405 to Welsh teaches stationary fin members that extend longitudinally within a heat exchanger tube. The fin members improve heat transfer by increasing the surface area for heat transfer within the tube. 
     Therefore, there exists a need in the art for a heat exchanger with variable heat transfer properties that can be varied on demand, is easily controlled, and can reduce the number of components intruding into the fluid stream. 
     SUMMARY OF THE INVENTION 
     A heat exchanger with variable heat transfer properties is disclosed. 
     In one aspect, the apparatus may include provisions for altering or varying the heat exchange characteristics of a heat exchanger by using one or more movable members that are connected to the inner surface of a heat exchange conduit. 
     In another aspect, the apparatus may include one or more stationary members to impede flow within the heat exchange conduit. 
     In another aspect, the stationary member free ends may be positioned downstream of the stationary member secured ends. 
     In another aspect, the movable members may be positioned in a number of desired positions depending on the heat transfer rate needed. 
     In another aspect, the desired position may include an extended position where the movable members may protrude into the flow path and impede flow inside the heat exchange conduit. 
     In another aspect, the desired position may be a distal position defined as the maximum extended position. 
     In another aspect, the desired position may include a retracted position, where the movable members minimally impede flow and are proximal to the portion of the heat exchange conduit inner surface that may be associated with the movable members. 
     In another aspect, the apparatus may include provisions for attaching and adjusting the movable members. 
     In another aspect, the apparatus may include provisions for impeding the range of motion of the movable members. 
     In another aspect, the apparatus may include a heat exchange system that includes a heat exchanger and a device that heats fluid as a byproduct of use. 
     In another aspect, the apparatus may include provisions for altering or varying the heat exchange characteristics of a heat exchanger at different sections of a heat exchange conduit. 
     In another aspect, the heat exchanger may include a casing conduit for directing the flow of a second fluid. 
     In another aspect, the heat exchanger may include a retracted movable member that resides within a recess in a heat exchanger conduit. 
     In another aspect, the heat exchanger may include movable members that translate or extend when moving from a retracted position to an extended position. 
     Other systems, methods, features and advantages of the invention will be, or will become, apparent to one of ordinary skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description and this summary, be within the scope of the invention, and be protected by the following claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts throughout the different views. 
         FIG. 1  is a schematic cut away diagram of a preferred embodiment of a heat exchanger; 
         FIG. 2  is a schematic cross-sectional view of a preferred embodiment of a heat exchanger with movable members in a retracted position; 
         FIG. 3  is a schematic cross-sectional view of a preferred embodiment of a heat exchanger with movable members in an extended position; 
         FIG. 4  is a preferred embodiment as shown in  FIG. 2  including a diagram of a possible flow field; 
         FIG. 5  is a preferred embodiment as shown in  FIG. 3  including a diagram of a possible flow field; 
         FIG. 6  is an enlarged schematic diagram of a preferred embodiment of a movable member; 
         FIG. 7  is a schematic diagram of a preferred embodiment of a heat exchange system including a heat exchanger and a device that heats fluid as a byproduct of use; 
         FIG. 8  is a schematic diagram of a preferred embodiment of a heat exchanger with variable heat transfer capabilities at different sections of the heat exchange conduit; 
         FIG. 9  is a schematic cut away diagram of a preferred embodiment of a heat exchanger including a casing conduit; and 
         FIG. 10  is a schematic end view of a preferred embodiment of a heat exchanger including a casing conduit. 
         FIG. 11  is a schematic cross sectional view of a preferred embodiment including a retracted movable member within a recess or protrusion of a heat exchange conduit. 
         FIG. 12  is a schematic cross sectional view of a preferred embodiment including an extended movable member and a protrusion on a heat exchange conduit. 
         FIG. 13  is a schematic cross sectional view of a preferred embodiment including retracted movable members slidably received within a recess of a heat exchange conduit. 
         FIG. 14  is a schematic cross sectional view of a preferred embodiment including extended movable members slidably received within a recess of a heat exchange conduit. 
         FIG. 15  is a schematic cross sectional view of another embodiment including retracted movable members slidably received within a recess of a heat exchange conduit. 
         FIG. 16  is a schematic cross sectional view of another embodiment including extended movable members slidably received within a recess of a heat exchange conduit 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention include a heat exchanger with variable heat transfer properties. In some embodiments, heat transfer properties may be varied by altering the flow of a first fluid through the heat exchanger. 
       FIG. 1  is a schematic cut away diagram of a preferred embodiment of a heat exchanger  101 . Referring to  FIG. 1 , a heat exchanger  101  may include inlet conduit  106  that carries a first fluid  105  to heat exchange conduit  104  through heat exchange conduit inlet  108 . Generally, first fluid  105  flows through heat exchange conduit interior  111 . Heat exchange conduit interior  111  may be defined or bounded by heat exchange conduit inner surface  109 . After passing through heat exchange conduit  104 , first fluid  105  may leave heat exchange conduit  104  and enter outlet conduit  112  through heat exchange conduit outlet  110 . 
     Heat exchange conduit  104  may facilitate heat transfer between first fluid  105  and a second fluid  107 . As depicted in  FIG. 1 , second fluid  107  may flow past one or more exterior surfaces of heat exchanger  101 . First fluid  105  may contact heat exchange conduit inner surface  109 , and second fluid  107  may contact one more exterior surfaces of heat exchanger  101 , including heat exchange conduit exterior surface  113 . This arrangement helps to transfer heat between first fluid  105  and second fluid  107 . 
     In some embodiments, the temperature of first fluid  105  may be higher than the temperature of second fluid  107 . In these cases, first fluid  105  may heat the heat exchange conduit  104  from heat exchange conduit inner surface  109  to heat exchange conduit exterior surface  113 . Second fluid  107  may cool heat exchange conduit  104  from heat exchange conduit exterior surface  113  to heat exchange conduit inner surface  109 . In this manner, heat may be transferred from first fluid  105  to second fluid  107 . In other embodiments, the temperature of second fluid  107  may be higher than the temperature of first fluid  105 . In these cases, second fluid  107  may heat the heat exchange conduit  104  from heat exchange conduit exterior surface  113  to heat exchange conduit inner surface  109 . First fluid  105  may cool heat exchange conduit  104  from heat exchange conduit inner surface  109  to heat exchange conduit exterior surface  113 . In this manner, heat may be transferred from second fluid  107  to first fluid  105 . 
     Some embodiments may include provisions for increasing or decreasing the rate of heat transfer of heat exchanger  101 . In some cases, the heat transfer rate may be controlled by controlling the fluid flow characteristics of one or more of the working fluids associated with heat exchanger  101 . Some embodiments may include provisions for altering or controlling the fluid flow properties within heat exchange conduit  104 . Preferably, these provisions include one or more mechanisms disposed within heat exchange conduit  104 . 
     In some embodiments heat exchanger  101  may be utilized as a different kind of device. For example, the apparatus may be used as a device to control fluid flow characteristics within a system. In other words, heat exchanger  101  may be used as a throttling device to control flow exiting heat exchange conduit  104 . 
     Referring to  FIG. 2 , heat exchange conduit  104  may encase stationary member  124 . By using stationary member  124  to impede flow through heat exchange conduit  104 , the flow rate of first fluid  105  may be controlled. Stationary member secured end  127  may be connected to heat exchange conduit inner surface  109 . Stationary member free end  125  may protrude into the flow path of heat exchange conduit  104 . 
     In different embodiments, the shape, size, orientation, and spacing of a stationary member  124  may vary. The shape of stationary member  124  may be any shape that impedes flow. Preferably, stationary member  124  is a rectangular flat plate. However, in other embodiments, stationary member  124  may be another shape. In one embodiment, stationary member  124  may protrude any distance into heat exchange conduit  104 . Preferably, stationary member free end  125  may protrude no more than half the height of heat exchange conduit  104 . In one embodiment, stationary member  124  may be designed so that stationary member free end  125  can range from any position upstream of stationary member secured end  127  to any position downstream of stationary member secured end  127 . In other words, stationary member  124  may be angled in an upstream direction, in a vertical position, or angled in a downstream direction. In an exemplary embodiment shown in  FIG. 2 , stationary member free end  125  may be positioned downstream of stationary member secured end  127  or rather, angled in a downstream direction. In other embodiments, the spacing of stationary member  124  from heat exchange conduit inlet  108  may vary. Stationary member  124  may be positioned within heat exchange conduit  104  any distance from heat exchange conduit inlet  108 . Preferably, the distance between stationary member  124  and heat exchange conduit inlet  108  may be no more than one-half the length of heat exchange conduit  104 . 
     Some embodiments may include more than one stationary member. In an exemplary embodiment shown in the figures, heat exchange conduit  104  may include a group of stationary members  131 . Similar to stationary member  124 , the group of stationary members  131  may be connected to and protrude into heat exchange conduit  104 . Also similar to stationary member  124 , the shape, size, orientation, and spacing of the group of stationary members  131  may vary. In addition, the spacing between individual members of the group of stationary members  131  may vary from one embodiment to another. Preferably, the distance between the individual members within a group of stationary members  131  may be approximately equal to the length of an individual stationary member within the group of stationary members  131 . 
     Typically, impeding flow in a conduit causes turbulence within the conduit and increased mixing. Increased mixing typically increases heat transfer. Therefore, the heat transfer rate between first fluid  105  and second fluid  107  may be increased. In addition, heat transfer between first fluid  105  and second fluid  107  may increase further as the impedance on first fluid  105  increases. Generally, the greater the number of stationary members  131  and the greater the extension of stationary members  131  into heat exchange conduit  104 , the greater the possibility of increasing heat transfer. 
     Generally, the flow field within a heat exchange conduit varies based on a number of factors including the size and position of heat exchange conduit inlet  108 , fluid speed, path obstructions, and smoothness of heat exchange conduit inner surface  109 . In a heat exchange conduit where the flow of a fluid is unobstructed and the walls are relatively smooth, the flow field is generally laminar. In an embodiment where there may be one stationary member  124  positioned within a heat exchange conduit  104 , first fluid  105  may impinge on stationary member  124  typically creating one or more eddies behind stationary member  124 . The faster the speed of the fluid the more likely one or more eddies will also be created in front of stationary member  124 . Generally, the further away portions of first fluid  105  are from stationary member  124  the less turbulent and more laminar the flow field becomes. 
     In an embodiment where there maybe two stationary members  124 ,  129  the flow field may look similar to the flow field where there may be only one stationary member  124 . Stationary members  124 ,  129  will typically cause eddies to form between stationary members  124 ,  129  and behind second stationary member  129 . 
     In another embodiment including a group of stationary members  131 , the flow field may look similar to the previously mentioned examples. However, the group of stationary members  131  will typically cause eddies to form between individual members of the group of stationary members  131  and behind the most downstream member of the group of stationary members  131 . 
     In addition to or instead of one or more stationary members, a movable member  122  may be used to impede flow through heat exchange conduit  104 , and thereby alter the flow characteristics and heat exchange characteristics of heat exchanger  101 . However, unlike the stationary members, movable member  122  may be adjusted during the operation of heat exchanger  101  to increase or decrease the flow rate and heat transfer rate. Movable member  122  may be positioned in a number of desired positions depending on the heat transfer rate needed. Desired positions may include retracted positions or extended positions. 
       FIG. 2  is a cross-sectional view of the preferred embodiment in a retracted position.  FIG. 3  is a cross-sectional view of the preferred embodiment in an extended position. Referring to  FIGS. 2 and 3 , heat exchange conduit  104  may encase movable member  122 . By using movable member  122  to impede flow through heat exchange conduit  104 , the flow rate of first fluid  105  may be controlled. Movable member secured end  123  may be connected to heat exchange conduit inner surface  109 . Movable member free end  121  may protrude into the flow path of heat exchange conduit  104 . 
     As illustrated in  FIG. 2 , movable member  122  may be positioned in a retracted position. In a retracted position, the entire body of movable member  122  may be positioned close to the portion of heat exchange conduit inner surface  109  associated with movable member  122 . Therefore, when movable member  122  may be in a retracted position, it may minimally interfere with or impede the flow of first fluid  105 . For example, in some cases, a portion of movable member  122  may touch the portion of heat exchange conduit inner surface  109  associated with movable member  122 . In another example, movable member  122  may be parallel to the portion of heat exchange conduit inner surface  109  associated with movable member  122 . In yet another example, a portion of each movable member  122  may minimally interfere with the flow of first fluid  105  by a depth less than five percent of the length of movable member  122 . 
     As illustrated in  FIG. 3 , movable member  122  may be positioned in an extended position. Preferably, the extended position may be a position different than the retracted position. Moving member  122  may assume a number of different extended positions. The distal position may be defined as the maximum extended position or the extended position that may be the maximum distance from the retracted position. 
     In the same manner as stationary member  124 , the shape, size, and spacing of movable member  122  may vary in different embodiments. The shape of movable member  122  may be any shape that impedes flow. Preferably, movable member  122  is a rectangular flat plate. However, in other embodiments, movable member  122  may be another shape. In some embodiments, movable member  122  may protrude any distance into heat exchange conduit  104 . Preferably, movable member free end  121  may protrude no more than half the height of heat exchange conduit  104 . However, in some embodiments, movable member free end  121  may protrude beyond half the height of heat exchange conduit  104 . In other embodiments, the spacing of movable member  122  from heat exchange conduit inlet  108  may vary. Movable member  122  may be positioned within heat exchange conduit  104  any distance from heat exchange conduit inlet  108 . Preferably, the distance between movable member  122  and heat exchange conduit inlet  108  may be no more than one-half the length of heat exchange conduit  104 . However, in other embodiments, this distance may vary. In embodiments where a stationary member  124  and a movable member  122  may be encased in heat exchange conduit  104 , it may also be preferable to size and space movable member  122  so that it does not contact stationary member  124 . 
     Some embodiments may include more than one movable member. In an exemplary embodiment shown in the figures, heat exchange conduit  104  may include a group of movable members  137 . Similar to movable member  122 , the group of movable members  137  may be connected to and protrude into heat exchange conduit  104 . Also similar to movable member  122 , the size and spacing of the group of movable members  137  may vary. In addition, the spacing between individual members of the group of movable members  137  may vary from one embodiment to another. In an exemplary embodiment, the distance between the individual members within a group of movable members  137  may be approximately equal to the length of an individual movable member within the group of movable members  137 . 
     However, the size and spacing of the group of movable members  137  does not necessarily need to correspond with the size and spacing of the group of stationary members  131 . In other words, an individual movable member may be larger or smaller than an individual stationary member, and the spacing between individual movable members may be larger or smaller than the spacing between individual stationary members. 
     In other embodiments that may use a movable member  122  or more than one movable member, the flow field within heat exchange conduit  104  may vary. Additionally, the flow field may vary based on the orientation or position of movable member  122  and other movable members. 
     In some cases, the flow field may resemble the flow fields that include stationary members  124 ,  129 , and  131 . However, in embodiments that include a movable member  122  opposite to the location of a stationary member  124 , less laminar flow may exist as movable member  122  moves from a retracted position to an extended position. In an extended position, first fluid  105  may impinge on movable member  122  typically creating one or more eddies within the flow field behind movable member  122 . 
     In an embodiment where there may be two extended movable members  122 ,  133 , the flow field may change. Movable members  122 ,  133  will typically cause eddies to form between movable members  122 ,  133  and behind second movable member  133 . 
     In another embodiment shown in  FIG. 3  including a group of movable members  137 , the flow field may look similar to the previously mentioned examples. However, a group of movable members  137  will typically cause eddies to form between individual movable members within a group of movable members  137  and behind the most downstream movable member within a group of movable members  137 . 
       FIG. 4  shows the preferred embodiment of  FIG. 2  including a diagram of a possible flow field.  FIG. 5  shows the preferred embodiment of  FIG. 3  including a diagram of a possible flow field. The majority of the reference numerals were removed from  FIGS. 4 and 5  so that the flow fields could be more clearly seen, but the same reference numerals used in  FIGS. 2 and 3  are utilized in  FIGS. 4 and 5 . In  FIG. 4 , the flow field near the retracted movable members  137  is generally laminar and turbulence increases near the stationary members  131 . Eddies can be seen before and after each stationary member. In  FIG. 5 , the movable members  137  and the stationary members  131  extend into the flow field and create turbulence throughout the conduit. Eddies can be seen before and after each movable and stationary member. 
     Preferably, heat exchanger  101  includes provisions for moving and controlling movable member  122 , and thereby, adjusting the flow field. Controlling the position of the movable member  122  allows a user to change the fluid flow conditions and heat transfer rate of heat exchanger  101  on demand. 
     In some embodiments, the control system used to control the motion of movable member  122  operates in a manner as to avoid or eliminate the intrusion of additional parts or components that protrude into heat exchange conduit  104 . In other words, some embodiments may include non-invasive control systems. 
     Some embodiments of heat exchanger  101  may include an electronic control system that can control the position of movable member  122 . Preferably, the control system includes a control unit able to remotely control the position of movable member  122  while heat exchanger  101  operates. The control system may use either a direct communications link or a wireless communications link to communicate with movable member  122 . In some embodiments, both direct and wireless communications methods may be used. 
     In different embodiments, ECU  132  may include a number of ports that facilitate the input and output of information and power. The term “port” means any interface or shared boundary between two conductors. In some cases, ports may facilitate the insertion and removal of conductors. Examples of these types of ports include mechanical connectors. In other cases, ports are interfaces that generally do not provide easy insertion or removal. Examples of these types of ports include soldering or electron traces on circuit boards. Some embodiments may include a given port or provision, while others may exclude it. 
     In a preferred embodiment as illustrated in  FIGS. 2 and 3 , the control system may comprise an electronic control unit (ECU)  132 , an ECU line  130 , electromagnet  128 , and movable member magnet  126 . In this embodiment, ECU  132 , ECU line  130 , and electromagnet  128  wirelessly communicate with movable member  122  and movable member magnet  126 . However, ECU line  130  provides a direct communications link between ECU  132  and electromagnet  128 . 
     In operation, ECU  132  first determines the degree of cooling or heating needed for first fluid  105 . ECU  132  may make this determination based on any desired parameter, including the heat exchange needs of other systems. Second, the heat exchange needs may be processed, and a desired position for movable member  122  maybe determined. Third, the position information may be transmitted to electromagnet  128  through ECU line  130 . ECU line  130  may provide the position information in the form of an electronic signal that may energize electromagnet  128 . Fourth, the energized electromagnet  128  generally creates a magnetic field. Electromagnet  128  may be attached to heat exchange conduit exterior surface  113  in the vicinity of movable member  122 . Finally, movable member magnet  126  may move or be repelled away from electromagnet  128  in response to the generated magnetic field. The characteristics of the magnetic field are typically dependant on the electronic signal transmitted through ECU line  130 . 
     In a preferred embodiment, movable member magnet  126  may be a permanent magnet. In other embodiments, movable member  122 , instead of including movable member magnet  126 , may be magnetized. 
     As previously indicated, ECU  132  may determine the heat exchange needs of first fluid  105 . For example, ECU  132  may determine that an increase in the heat transfer rate is needed. The ECU may process the heat transfer information and may determine and transmit position information electronically to electromagnet  128  using ECU line  130 . The initial position of one or more movable members  122 ,  137  may be a retracted position or an extended position. The electronic signal causes an increase in the repulsion between electromagnet  128  and movable member magnet  126  resulting in an increase in the extension of one or more movable members  122 ,  137 . 
     If ECU  132  determines that less heat transfer is needed, the ECU may send position information electronically to electromagnet  128  using ECU line  130 . The altered electronic signal causes a decrease in the repulsion between electromagnet  128  and movable member magnet  126  resulting in a decrease in the extension of one or more movable members  122 ,  137 . 
     If ECU  132  determines that a minimum amount of heat transfer is needed, the ECU may transmit position information electronically with a reversed polarity to electromagnet  128  using ECU line  130 . Electromagnet  128  creates a magnetic field that attracts movable member  122 ,  137  and causes movable members  122 ,  137  to move from an initial position to a retracted position. 
     In an alternative embodiment, if the ECU determines that a minimum amount of heat transfer is needed, the ECU may cease to transmit position information electronically. Instead, the force of first fluid  105  may push movable members  122 ,  137  towards a retracted position. When movable member magnet  126  nears the metal core of electromagnet  128 , the natural attraction between the two allows movable members  122 ,  137  to reach a retracted position. 
     Some embodiments may include additional provisions to restrict the movement or range of motion of movable member  122 . These provisions assist in controlling the orientation of movable member  122  so that the flow rate and heat transfer rate can be more precisely controlled. 
     In order to restrict the movement of movable member  122 , some embodiments may include provisions for attaching and adjusting movable member  122  with respect to heat exchange conduit  104 . An embodiment may include a pivoting mechanism that allows movable member  122  to rotate into and out of the flow field within heat exchange conduit  104 . 
       FIG. 6  is an enlarged schematic view of a preferred embodiment of movable member  122  and a mechanism that may enable movable member  122  to pivot within heat exchange conduit  104 . Referring to  FIG. 6 , a portion of heat exchange conduit inner surface  109  may include points of attachment for movable member  122 . The points of attachment may include first hinge element  134  and second hinge element  135 . 
     First and second hinge elements  134 ,  135  may be configured as protrusions that extend from heat exchange conduit inner surface  109  towards the center of heat exchange conduit  104 . First and second hinge element secured ends  139 ,  143  may be connected to heat exchange conduit inner surface  109 . First and second hinge element free ends  141 ,  145  may be designed to extend a minimal amount into heat exchange conduit  104 . The lengths of first and second hinge elements  134 ,  135  may be at least the thickness of movable member  122  and provide enough clearance to move movable member  122  from a retracted position to the distal position. 
     First and second hinge element free ends  141 ,  145  may include a hole. Movable member secured end  123  may also include a hole that extends through the width of movable member  122 . Shaft  136  may be inserted through all three holes to allow movable member  122  to move and align with respect to a generated magnetic field. Shaft  136  may also include a mechanism to maintain the shaft within all three holes. 
     If ECU  132  determines an increase, decrease, or minimal heat transfer rate is needed, first and second hinge elements  134 ,  135  and shaft  136  allow movable member free end  123  to move to a retracted position, a distal position, or any extended position between the retracted and distal positions. As depicted in  FIG. 6 , movable member  122  represented with solid lines, may be a retracted position, and movable member  122  represented with broken lines, may be an extended position. 
     Some embodiments may also include provisions for restricting the range of motion of movable member  122 . Referring to  FIG. 6 , a stop  138 , positioned behind movable member  122 , may be used to prevent movable member  122  from moving beyond the distal position. Stop  138  may be a protrusion attached to and extending into heat exchange conduit  104  in a similar manner as first and second hinge elements  134 ,  135 . Preferably, stop  138  may be the same length as first and second hinge elements  134 ,  135 . 
     In different embodiments, the spacing and orientation of stop  138  may vary based on the distal position of movable member  122 . For example, stop  138  may be spaced a distance from movable member  122  so that stop  138  does not contact movable member  122  unless movable member  122  shifts to a distal position. In addition, stop  138  may be designed so that stop free end  149  can range from any position upstream of stop secured end  147  to any position downstream of stop secured end  147 . In other words, stop  138  may be angled in an upstream direction, in a vertical position, or angled in a downstream direction. Therefore, the orientation of stop  138  may coincide with the orientation of the distal position. 
       FIGS. 7-10  show alternative embodiments of the heat exchanger. These alternative embodiments include the installation of heat exchanger  101  within a heat exchange system, control of heat exchange at multiple sections of heat exchange conduit  104 , and a heat exchanger including a casing conduit. 
     Some embodiments may involve the installation of heat exchanger  101  within a heat exchange system. The heat exchange system includes components that allow first fluid  105  to be heated and cooled. 
       FIG. 7  is a schematic diagram of a preferred embodiment of a heat exchange system including a heat exchanger and a device that heats fluid as a byproduct of use. Referring to  FIG. 7 , first fluid  105  may be heated by device  140 . First fluid  105  may then flow through device outlet  146  and into inlet conduit  106 . First fluid  105  then flows through heat exchange conduit inlet  108  and into heat exchange conduit  104 . After exiting heat exchange conduit  104  through heat exchange conduit outlet  110 , first fluid  105  flows into outlet conduit  112 . Outlet conduit  112  returns first fluid  105  to device  140  through device inlet  148 . 
     The heat exchange rate of heat exchanger  101  may be dependant on one or more properties related to device  140 . For example, sensor  142  may sense a thermodynamic property of first fluid  105  or device  140 . Sensor  142  may then transmit the sensed thermodynamic property to ECU  132  through sensor line  144 . Sensor line  144  may provide the sensed thermodynamic property in the form of an electronic signal. ECU  132  may have a table that includes the value of a thermodynamic property and the corresponding position information to be transmitted to electromagnet  128 . ECU  132  may then transmit the corresponding position information to electromagnet  128  through ECU line  130 . Heat exchanger  101  of  FIG. 7  may then function similarly to the previously described embodiments. 
     Device  140  may be any device that mainly functions to heat a fluid as a byproduct of use. For example, in some embodiments, device  140  may be a transmission, and first fluid  105  may be transmission fluid. 
     Sensor  142  may be capable of sensing one or more thermodynamic properties and may be positioned in various locations within the heat exchange system. Preferably, sensor  142  may sense temperature. In some embodiments, sensor  142  may be located within or on an exterior surface of device  140 . Sensor  142  may be positioned to sense the interior temperature of device  140  or the temperature of first fluid  105  inside device  140 . Preferably and as shown in  FIG. 7 , sensor  142  may be positioned on an exterior surface of device  140 . 
     In the preferred embodiment of  FIG. 7 , the communications link between sensor  142  and ECU  132  may be sensor line  144 , a direct communications link. However, like the communications link between ECU  132  and electromagnet  128 , the communications link between sensor  142  and ECU  132  may be a direct communications link or a wireless communications link. 
     Some embodiments may include provisions for altering or varying the heat exchange characteristics of a heat exchanger at different sections of the heat exchange conduit  104 . These provisions allow for discrete control of the flow rate and the heat transfer rate throughout heat exchange conduit  104 . 
       FIG. 8  is a schematic diagram of a preferred embodiment of a heat exchanger with variable heat transfer capabilities at different sections of the heat exchange conduit. The embodiment of  FIG. 8  may function similarly to previously mentioned embodiments. Referring to  FIG. 8 , first fluid  205  may flow through conduit  204 . Flow in conduit  204  may be impeded by one or more stationary members  224 ,  254 . Flow may also be impeded by one or more movable members. 
     The position of two or more movable members may be individually controlled by ECU  250 . For example, movable members  238 ,  240 , and  242  may be individually controlled by ECU  250 . When ECU  250  determines the heat exchange needs of first fluid  205 , ECU  250  may determine that different heat transfer rates within heat exchange conduit  204  are needed. ECU  250  may make this determination based on any desired parameter, including the heat exchange needs of other systems. The heat exchange needs are processed, and desired positions for movable members  238 ,  240 , and  242  may be determined. The position information may be transmitted to electromagnets  244 ,  246 , and  248  through ECU lines  232 ,  234 , and  236  respectively. ECU lines  232 ,  234 , and  236  may provide the position information in the form of an electronic signal to energize electromagnets  244 ,  246 , and  248 . Each electromagnet  244 ,  246 , and  248  may be attached to heat exchange conduit exterior surface  252  in the vicinity of movable members  238 ,  240 , and  242  respectively. Generally, the energized electromagnets  244 ,  246 , and  248  create their own magnetic fields, and each movable member  238 ,  240 , and  242  may move or be repelled away from a respective electromagnet in response to an associated magnetic field. Therefore, the position of each movable member  238 ,  240 , and  242  may differ within heat exchange conduit  104 . As illustrated in  FIG. 8 , movable member  238  may be in an extended position, while movable member  240  may be in a different extended position and movable member  242  may be in a retracted position. 
     In some embodiments, two or more groups of movable members  226 ,  228 , and  230  may be individually controlled by ECU  250 .  FIG. 8  shows an exemplary embodiment of how ECU  250  may control the position of each movable member group  226 ,  228 , and  230  based on the position information transmitted through ECU lines  232 ,  234 , and  236 . In this embodiment, each group of movable members may be moved to a specific position. As shown in  FIG. 8 , the group of movable members  226  may be in an extended position, while the group of movable members  228  may be in a different extended position and the group of movable members  230  may be in a retracted position. 
       FIG. 8  illustrates a portion of heat exchange conduit  204  and three groups of movable members  226 ,  228 , and  230 . In addition,  FIG. 8  shows three movable members within each group of movable members  226 ,  228 , and  230 . Heat exchange conduit  204  may extend in either direction to accommodate any desired number of groups of movable members and any desired number of movable members within each group of movable members. 
     The flow field for an embodiment that includes three groups of movable members  226 ,  228 , and  230  and a group of stationary members  254  may look similar to the flow fields described and diagrammed for  FIGS. 2-5 . The flow field will vary based on the position or orientation of each member or group of members. Referring to  FIG. 8 , a group of stationary members  254  typically cause eddies to form before and after individual stationary members within the group of stationary members  254 . A group of extended movable members  226  and  228  typically cause eddies to form before and after each individual movable member. However, the flow field between movable members  228  and stationary members  254  may be less turbulent than the flow field between movable members  226  and stationary members  254  because movable members  226  may be extended further into the flow field. A group of retracted movable members  230  may allow a generally laminar flow field to form near movable members  230 , and turbulence typically increases near stationary members  254 . In other words, the flow field may become less turbulent as the fluid flows from left to right through heat exchange conduit  204 . 
     In the embodiments of  FIGS. 1-8 , second fluid  107  may flow freely past one or more exterior surfaces of heat exchanger  101 . However, other embodiments may include provisions for channeling second fluid  107  directly to and around heat exchange conduit  104 . The provisions may provide for more continuous and consistent heat transfer. 
       FIG. 9  is a schematic cut away diagram of a preferred embodiment of a heat exchanger including a casing conduit.  FIG. 10  is a schematic end view of a preferred embodiment of a heat exchanger including a casing conduit. Referring to  FIGS. 9 and 10 , an encased heat exchanger  100  may include casing inlet conduit  114  that carries second fluid  107  to casing conduit  102  through casing conduit inlet  116 . Generally, second fluid  107  flows through casing conduit interior  103 . Casing conduit interior  103  may be defined or bounded by casing conduit inner surface  115 . After passing through casing conduit  102 , second fluid  107  may leave casing conduit  102  and enter casing outlet conduit  120  through casing conduit outlet  118 . The flow path of first fluid  105  may be similar to the previously mentioned embodiments. 
     Generally, heat exchange conduit  104  resides within casing conduit interior  103 . Conduits  102  and  104  may be sealed so that first fluid  105  does not leak into casing conduit interior  103  and second fluid  107  does not leak into heat exchange conduit interior  111 . 
     Other embodiments of encased heat exchanger  100  may include provisions for altering the flow rate of second fluid  107 , and therefore, increasing or decreasing the heat transfer rate of encased heat exchanger  100 . These provisions may include a mechanism, such as a pump, for controlling the flow rate of second fluid  107 . The provisions may also include stationary members and movable members located on heat exchange conduit exterior surface  113 , casing conduit inner surface  115 , and casing conduit exterior surface  117 . 
     Some embodiments may include provisions for recessing a movable member within a heat exchange conduit when the movable member may be in the retracted position. These provisions may allow for minimal interference of the movable member with the flow of fluid when the movable member is in the retracted position. 
       FIG. 11  is a schematic cross sectional view of a preferred embodiment including a retracted movable member within a recess or protrusion of a heat exchange conduit.  FIG. 12  is a schematic cross sectional view of a preferred embodiment including an extended movable member and a protrusion on a heat exchange conduit. Referring to  FIGS. 11 and 12 , heat exchange conduit  304  may include a heat exchange conduit protrusion  356  that bounds heat exchange conduit recess  357 . Movable member  322  may reside entirely or partially within heat exchange conduit recess  357 . Movable member secured end  323  may be connected to heat exchange conduit protrusion inner surface  359 . 
     When movable member  322  is in a retracted position, movable member  322  may reside entirely in heat exchange conduit recess  357 . In a preferred embodiment, movable member side  361  lies flush with heat exchange conduit inner surface  309  when movable member  322  is in the retracted position. When movable member  322  is in an extended position, movable member  322  may protrude into the flow path of heat exchange conduit  304 . 
     In the same manner as movable member  122 , the shape, size, and spacing of movable member  322  may vary in different embodiments. A notable difference between movable member  122  and movable member  322  may be the preferred shape. Preferably, movable member  322  may be wedge-shaped. However, in other embodiments, movable member  322  may be of any shape including a rectangular flat plate. 
     The shape, size, and spacing of heat exchange conduit recess  357  may vary in different embodiments. The shape and size of heat exchange conduit recess  357  may be any shape and size that allows at least a portion of movable member  322  to lie within heat exchange conduit recess  357 . Preferably, heat exchange conduit recess  357  may be larger than and shaped similarly to movable member  322  and have only enough clearance to allow movable member  322  to move from a retracted position to an extended position. The spacing of heat exchange conduit recess  357  from other portions of heat exchange conduit  304  may be such that heat exchange conduit recess  357  aligns with the location and orientation of movable member  322 . 
     The shape, size, and spacing of heat exchange conduit protrusion  356  may vary in different embodiments. Heat exchange conduit protrusion interior surface  359  bounds heat exchange conduit recess  357 . Therefore, heat exchange conduit protrusion interior surface  359  has the shape and size of heat exchange conduit recess  357 . The shape of heat exchange conduit protrusion exterior surface  363  may be any shape. Preferably, the shape may be similar to the shape of heat exchange conduit protrusion interior surface  359  and provide sufficient surface area for the heat exchange conduit&#39;s control system to communicate with movable member magnet  326 . However, the shape of heat exchange conduit protrusion exterior surface  363  need not be shaped similarly to heat exchange conduit protrusion interior surface  359 . Preferably, the size of heat exchange conduit protrusion exterior surface  363  may be any size that may be larger than the size of heat exchange conduit recess  357 . The spacing of heat exchange conduit protrusion  356  from other portions of heat exchange conduit  304  may be such that heat exchange conduit protrusion  356  aligns with the location of movable member  322 . 
     In the same manner as previous embodiments, some embodiments may include more than one movable member. In these embodiments, each movable member preferably has its own heat exchange conduit protrusion and heat exchange conduit recess. However, in other embodiments, one or more movable members may reside in one heat exchange conduit protrusion and an associated heat exchange conduit recess. Similar to movable members  137 , the shape, size, orientation, and spacing of the group of movable members may vary. In addition, the spacing between individual members of a group of movable members may vary from one embodiment to another. Preferably, the distance between the individual members within a group of movable members may be approximately equal to the length of an individual movable member within the group of movable members. 
     Similar to previous embodiments, heat exchange conduit  304  may include first fluid  305  flowing through the heat exchange conduit interior  311 . In embodiments that may use a movable member  322  or more than one movable member, the flow field within heat exchange conduit  304  may vary. Additionally, the flow field may vary based on the orientation or position of movable member  322  and other movable members. The flow field may resemble those previously described for movable members  122 ,  133 , and  137 . In addition, because movable members  322 ,  333 , and  337  may be recessed when in a retracted position, the flow may be more laminar than in previous embodiments where the movable members may not be recessed. 
     Embodiments including movable member  322  may also include a control system comprising an electromagnet and other electrical components as described in previous embodiments. The electromagnet may be activated to attract or repel a movable member magnet depending on the heat transfer needed. Electromagnet  328  may be located near the heat exchange conduit protrusion exterior surface  363  and preferably in the vicinity of movable member  322  and movable member magnet  326 . 
     Some embodiments may include additional provisions to restrict the movement or range of motion of movable member  322 . These provisions assist in controlling the orientation of movable member  322  so that the flow rate and heat transfer rate can be more precisely controlled. For example, heat exchange conduit recess  357  may include a pivoting mechanism that allows movable member  322  to move from a retracted position, within heat exchange conduit recess  357 , to an extended position, where movable member free end  321  moves to into heat exchange conduit  304  to impede flow. The pivoting mechanism may be attached to movable member  322  near movable member secured end  323  and to heat exchange conduit protrusion interior surface  359 . The pivoting mechanism may be similar to that discussed in previous embodiments and illustrated in  FIG. 6 . This mechanism may include protrusions that extend toward movable member  322  from heat exchange conduit protrusion interior surface  359  and attach to movable member  322  via shaft  336 . 
     Some embodiments may also include provisions for restricting the range of motion of movable member  322 . A stop  338  may be used to prevent movable member  322  from moving beyond the distal position. Stop  338  may be an extension of heat exchange conduit  304 , and it may extend into heat exchange conduit recess  357 . To contact stop  338  and prevent movable member  322  from moving beyond a distal position, movable member  322  may include movable member extension  358 . When movable member  322  moves from a retracted position to the distal position, movable member extension side  360  contacts stop side  362  and prevents movable member  322  from moving beyond the distal position. 
     In different embodiments, the shape, length, and orientation of stop  338  and movable member extension  358  may vary based on the distal position of movable member  322 . Stop  338  and movable member extension  358  may be of any shape, length, or orientation. For example, stop  338  may protrude at an angle into heat exchange conduit recess  357 , at an angle into heat exchange conduit interior  311 , or at no angle and lie parallel to heat exchange conduit  304 . Preferably, stop  338  and movable member extension  358  do not contact each other unless movable member  322  shifts to a distal position. 
     Embodiments of a heat exchange system including a heat exchanger and a device that heats fluid as a byproduct of use, as illustrated in  FIG. 7 , may incorporate one or more movable members that may be recessed within a heat exchange conduit protrusion. Heat exchanger  101  may otherwise function similarly to previously described embodiments. 
     Embodiments of a heat exchanger with variable heat transfer capabilities at different sections of the heat exchange conduit, as illustrated in FIG.  8 , may incorporate one or more movable members that may be recessed within heat exchange conduit protrusion. The heat exchanger of  FIG. 8  may otherwise function similarly to previously described embodiments. 
     Embodiments of a heat exchanger with a casing conduit, as illustrated in  FIGS. 9-10 , may incorporate one or more movable members that may be recessed within a heat exchange conduit protrusion. Heat exchanger  100  may otherwise function similarly to previously described embodiments. 
     Some embodiments may include provisions for translating or extending a movable member from a retracted position to an extended position. These provisions impede flow within a heat exchange conduit without the use of a pivoting mechanism. 
       FIG. 13  is a schematic cross sectional view of a preferred embodiment including retracted movable members within a recess of a heat exchange conduit.  FIG. 14  is a schematic cross sectional view of a preferred embodiment including extended movable members within a recess of a heat exchange conduit. Referring to  FIGS. 13 and 14 , heat exchange conduit  404  may include a heat exchange conduit recess  457 . Movable member  422  may reside entirely or partially within heat exchange conduit recess  357 . Movable member secured end  423  may be connected to movable body  464  at movable body side  465 . 
     When movable member  422  and movable body  464  may be in a retracted position, movable member  422  and movable body  464  may reside entirely within heat exchange conduit recess  457 . Movable member free end  421  may have an extreme end that defines a tip surface. In a preferred embodiment, the tip surface may lie flush with or in the same plane as heat exchange conduit inner surface  409 . When movable member  422  and movable body  464  are in an extended position, movable member  422  may protrude into the flow path of heat exchange conduit  404 . 
     In the same manner as movable member  122  and  322 , the shape, size, and spacing of movable member  422  may vary in different embodiments. Similar to movable member  322 , movable member  422  may be of varying shapes. Preferably, movable member  422  may be wedge-shaped. However, in other embodiments, movable member  422  may be of any shape including a rectangular flat plate.  FIG. 15  is a schematic cross sectional view of another embodiment including retracted movable members within a recess of a heat exchange conduit.  FIG. 16  is a schematic cross sectional view of another embodiment including extended movable members within a recess of a heat exchange conduit.  FIGS. 15 and 16  show a movable member  422  that has a rectangular flat plate shape. 
     In the same manner as heat exchange conduit recess  357 , the shape, size, and spacing of heat exchange conduit recess  457  may vary in different embodiments. The shape and size of heat exchange conduit recess  457  may be any shape and size that allows at least a portion of movable member  322  and movable body  464  to lie within heat exchange conduit recess  457 . Preferably, heat exchange conduit recess  457  may be larger than movable member  422  and movable body  464  and shaped similarly to movable body  464 . Preferably, heat exchange conduit recess  457  may also have only enough clearance to allow movable member  422  and movable body  464  to move from a retracted position to an extended position. The spacing of heat exchange conduit recess  457  from other portions of heat exchange conduit  404  should be such that heat exchange conduit recess  457  aligns with the location and orientation of movable member  422  and movable body  464 . 
     Some embodiments may include more than one movable member. In an exemplary embodiment shown in  FIGS. 13-16 , heat exchange conduit  404  may include a group of movable members  437 . In an embodiment, each movable member may be connected to one movable body and reside in one heat exchange conduit recess. Preferably, a group of movable members  437  may be connected to a single movable body  464  and reside in one heat exchange conduit recess  457 . Similar to movable member  422 , the free ends of a group of movable members  437  may have extreme ends that defining a tip surface. In a preferred embodiment, the tip surfaces may lie flush with or in the same plane as heat exchange conduit inner surface  409 . Similar to movable members  137 , the shape, size, orientation and spacing of the group movable members  437  may also vary. In addition, the spacing between individual members of the group of movable members  437  may vary from one embodiment to another. Preferably, the distance between the individual movable members within a group of movable members  437  may be approximately half the length of an individual movable member within the group of movable members  437 . 
     Similar to previous embodiments, heat exchange conduit  404  may include first fluid  405  flowing through heat exchange conduit interior  411 . In embodiments that may use a movable member  422  or more than one movable member, the flow field within heat exchange conduit  404  may vary. Additionally, the flow field may vary based on the orientation or position of movable member  422  and other movable members. The flow field may resemble those previously described for movable members  122 ,  133 , and  137 . In addition, because the movable members  422 ,  433 , and  437  may be recessed when in a retracted position, the flow may be more laminar than in previous embodiments where the movable members may not be recessed. 
     Embodiments may also include a control system comprising an electromagnet and other electrical components as described in previous embodiments. The electromagnet may be activated to attract or repel a movable member magnet depending on the heat transfer needed. Electromagnet  428  may be located near heat exchange conduit exterior surface  413  and preferably in the vicinity of movable member  422  and movable member magnet  426 . 
     Some embodiments may include additional provisions to restrict the movement or range of motion of movable member  422 . These provisions assist in controlling the position of movable member  422  so that the flow rate and heat transfer rate can be more precisely controlled. For example, heat exchange conduit recess  457  may include a sliding mechanism that allows movable member  422  and movable body  464  to move from a retracted position, within heat exchange conduit recess  457 , to an extended position, where movable member free end  421  moves into heat exchange conduit  404  to impede flow. 
     The sliding mechanism may be attached to movable body  464 . Sliding element  466  may be configured in one or more pieces that extend wholly or partially through movable body  464 . Sliding element  466  may also be slidably connected to heat exchange conduit recess surface  459 . However, sliding element  466  may not continuously contact heat exchange conduit recess surface  459 . Sliding element  466  may be designed to extend towards heat exchange conduit recess surface  459  so that movable member  422  and movable body  464  have little clearance to move laterally. Heat exchange conduit recess  457  may also be designed so that the portions that receive sliding element  466  may be slots. 
     Some embodiments may also include provisions for restricting the range of motion of movable member  422 . Stops  468  and  470  may be used to prevent movable member  422  from moving beyond the distal position. Stops  468  and  470  may be extensions of heat exchange conduit  404  that extend into heat exchange conduit recess  457 . To contact stops  468  and  470  and prevent movable member  422  from moving beyond the distal position, sliding element  466  may be utilized. When movable member  422  moves from a retracted position to the distal position, the ends of sliding element  466  may contact sides  472  and  474  of stops  468  and  470  and prevent movable member  422  from moving beyond the distal position. 
     In different embodiments, the shape, length, and orientation of stops  468  and  470  and sliding element  466  may vary based on the distal position of movable member  422 . Stops  468  and  470  and sliding element  466  may be of any shape, length, or orientation. For example, stops  468  and  470  may protrude at an angle into heat exchange conduit recess  457 , at an angle into heat exchange conduit interior  411 , or at no angle and lie parallel to heat exchange conduit  404 . Preferably, stops  468  and  470  and sliding element  466  do not contact each other unless movable member  422  shifts to a distal position. 
     Embodiments of a heat exchange system including a heat exchanger and a device that heats fluid as a byproduct of use, as illustrated in  FIG. 7 , may incorporate one or more movable members  422 ,  437  that move from a retracted position to an extended position. Heat exchanger  101  may otherwise function similarly to previously described embodiments. 
     Embodiments of a heat exchanger with variable heat transfer capabilities at different sections of the heat exchange conduit, as illustrated in  FIG. 8 , may incorporate one or more movable members  422 ,  437  that move from a retracted position to an extended position. The heat exchanger of  FIG. 8  may otherwise function similarly to previously described embodiments. 
     Embodiments of a heat exchanger with a casing conduit, as illustrated in  FIGS. 9-10 , may incorporate one or move movable members  422 ,  437  that move from a retracted position to an extended position. Heat exchanger  100  may otherwise function similarly to previously described embodiments. 
     While various embodiments of the invention have been described, the description is intended to be exemplary, rather than limiting and it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible that are within the scope of the invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents. Also, various modifications and changes may be made within the scope of the attached claims.