Thermal energy transfer apparatus and method
TECHNICAL FIELD 
     The present invention relates to thermal energy transfer apparatus and to a method for efficiently transferring thermal energy between media. 
     BACKGROUND OF PRIOR ART 
     One example of a prior heat exchanger used, for example, in a room heating convector apparatus includes, for example, a pipe through which hot water flows, plural fins on the pipe, and a blower for blowing air across the pipe and fins so that the air is heated during such passage. Another example of a conventional heat exchanger is the radiator apparatus of a motor vehicle, and still other examples are domestic and commercial furnaces, boilers, hot water heaters, etc. 
     The various prior heat exchanger are inefficient in a number of respects. Typically a liquid flowing through a pipeline of the heat exchanger generally experiences laminar flow in which there is minimal boundary layer movement relative to the central stream area, and the slow motion at the boundary layer area tends to create a thermal insulating effect. Thus, heat transfer to the material of the pipeline is impeded by the boundary layer insulation and the laminar flow with relatively higher velocity center-stream conditions further reduce the transfer of heat energy to the heat transfer medium of the pipeline. Moreover, to increase the outside surface area of the heat exchanger, which is typically designed to have air or other gas blown thereacross, fins are welded or otherwise secured to the outside surface of the pipeline. The connections of the fins to the outside surfaces of the pipeline frequently impede the conduction of heat between the pipeline material and the major portion of the fin material. Additionally, at such junctions, there frequently is a build-up of heat, which further impedes the conduction of heat thereat. 
     Other disadvantages with prior art heat exchangers are their large size, equipment cost, and operation cost. A disadvantage of present automotive radiators is the large size and weight thereof. These all contribute negatively to principles of conservation of energy, natural resources, capital, space, etc. 
     There are, of course, three types of heat transfer, namely conduction, convection and radiation. Conduction is the most efficient and most heat exchangers employ both conduction and convection. However, conduction with respect to fluid in the heat exchanger is impeded and made inefficient due to the boundary layer insulation effect mentioned above. 
     SUMMARY OF THE INVENTION 
     In the present invention, though, conduction efficiency is improved, for example, by providing large surface areas at which conduction may occur and by breaking up boundary layers to avoid insulating effects. 
     In accordance with the present invention there are disclosed thermal energy transfer apparatus and a method of thermal energy transfer that are improved over prior apparatus and methods. The invention provides for improved thermal energy transfer efficiency ordinarily accomplished in a reduced volume and at reduced equipment and operational cost than was heretofore possible. 
     In accordance with one aspect of the present invention a thermal energy transfer apparatus for transferring thermal energy between plural media includes thermally conductive mesh-like means having a relatively large cumulative surface area for transferring thermal energy therethrough, a pair of thermally conductive discs engaged with the mesh-like means for transferring thermal energy with respect to the latter, and a holder for holding the mesh-like means and the discs in relatively fixed operative spacial relation. In accordance with a more specific aspect of the invention, the mesh-like means disperses fluid flowing therethrough while simultaneously effecting efficient and substantial thermal energy transfer therewith and the discs direct the fluid into and receive fluid from the mesh-like means. 
     According to another aspect, a thermal energy transfer apparatus includes fluid flow means for conducting the flow of fluid therethrough including dispersing means for dispersing the fluid flowing through the fluid flow means, and thermal energy transfer means for transferring thermal energy with respect to the dispersing means for transfer between the latter and such fluid flowing therethrough. 
     According to another aspect, a thermal energy transfer apparatus includes fluid dispersing means for dispersing fluid flowing therethrough, fluid delivery means for delivering fluid to the fluid dispersing means, fluid receiving means for receiving fluid having flowed through the fluid dispersing means, and thermal energy transfer means for transferring thermal energy with respect to the fluid dispersing means for transfer between the latter and such fluid flowing therethrough. 
     According to another aspect of the invention, a method of transferring thermal energy with respect to a fluid flowing in a heat exchanger includes dispersing the fluid as it flows through the heat exchanger using a dispersing medium and transferring thermal energy with respect to the dispersing medium for transfer between the latter and the fluid being dispersed thereby. 
     The present invention will be described herein with respect to a heat exchanger in which it is intended to deliver heat to or to remove heat from one water medium. However, it will be appreciated that such medium actually may be plural media and such media may be another liquid, gas or solid. It will be appreciated, too, that the use of the phrase &#34;heat exchanger&#34; herein broadly means a thermal energy transfer apparatus which may deliver cold or remove cold from the described one or disclosed plural media. 
     With the foregoing introduction and following detailed description in mind, it is a primary object of the present invention to provide a thermal energy transfer apparatus and method that are improved in the disclosed respects. 
     Another object is to improve the efficiency of thermal energy transfer in a heat exchanger or the like, especially by providing a relatively large amount of conductive energy transfer. 
     An additional object is to transfer thermal energy directly between two environments, e.g. between the inside and outside of a heat exchanger. 
     A further object is to transfer thermal energy between plural fluids. 
     Still another object is to reduce or to minimize boundary layer thermal energy insulating effects in a heat exchanger. 
     Still an additional object is to reduce the cost, size, weight and cost of operation of heat exchangers, such as water heaters, radiators, boilers, furnaces, air conditioning equipment, heat pumps and other equipment. 
     Still a further object is to increase the heat exchange surface areas at which thermal energy is transferred relative to a fluid. 
     Even another object is to improve the uniformity of temperature and thermal energy transfer in a fluid, especially by causing a turbulence-like mixing while maintaining over-all laminar flow characteristics of fluid flowing through a heat exchanger. 
     Even an additional object is to minimize thermal energy build-up and other so-called bottlenecks at the transfer media or elsewhere in a heat exchanger. 
     These and other objects and advantages of the present invention will become more apparent as the following description proceeds. 
     To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described in the specification and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but several of the various ways in which the principles of the invention may be employed. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     In the annexed drawings: 
     FIG. 1 is a side view, partly broken away in section, of a heat exchanger in accordance with the present invention; 
     FIG. 2 is a partial exploded three-quarters view of the heat exchanger of FIG. 1; 
     FIG. 3 is a partial three-quarters exploded view of an alternate embodiment of heat exchanger in accordance with the invention; 
     FIG. 4 is a front elevation view of another alternate embodiment of heat exchanger in accordance with the invention; 
     FIGS. 5 and 6 are, respectively, side elevation and section views, the latter being taken along the lines 6--6 of FIG. 5, of an additional alternate embodiment in accordance with the invention; 
     FIG. 7 is a schematic illustration of a plan view of a further alternate embodiment of heat exchanger in accordance with the invention; 
     FIG. 8 is a schematic illustration of still a further alternate embodiment of heat exchanger in accordance with the invention; and 
     FIG. 9 is a schematic illustration of still an additional alternate embodiment of heat exchanger in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION 
     Referring now in detail to the drawings, and initially to FIGS. 1 and 2, a thermal energy transfer apparatus in accordance with the present invention and hereinafter referred to generally as a heat exchanger for convenience of description, as was mentioned above, is generally indicated at 1. The fundamental components of the heat exchanger 1 include a principal heat transferring medium 2 and thermal energy conducting or heat exchange plates or discs 3, 4. The medium 2 is held in a support ring 5, and the assemblage of media 2, discs 3, 4, and support rings 5 is held together or secured as an integral structure between end plates or blocks 6, 7 by threaded fastening rods 8 and fastener nuts 9. 
     In the preferred embodiment and best mode of the invention, the heat exchanger 1 is intended to facilitate raising the temperature of one fluid, say water, which flows through the heat exchanger 1, by applying heat to the heating zone 10 externally of the heat exchanger 1. Accordingly, water supplied via an inlet pipe or hose 11 passes through an inlet fitting 12 in the inlet block 6, through an internal flow path 13, through an outlet fitting 14 in the outlet block 7 and to a downstream location via an outlet pipe or hose 15. The fluid flowing through the internal flow path 13 may be another gas or liquid other than water. Heat may be applied to the heating zone 10 by the hot products of combustion from, for example, a gas or oil flame, not shown, by hot water or other fluid, by electric heating means, etc. It is the object of the heat exchanger 1 to transfer heat from the heating zone 10 to the internal fluid flowing through the internal flow path 13 while preferably maintaining fluidic and/or other isolation between the internal flow path 13 and the heating zone 10, for example, to avoid water leakage. 
     In the preferred embodiment as well as in the additional embodiments disclosed hereinafter, the medium 2 is of a material that is a good conductor of thermal energy, for example, copper, aluminum, or like material. Moreover, such material should not be affected by fluid contacting the same, or at least such affectation should be relatively minimized. The general configuration of the heat transfer medium 2 preferably is disc-like with faces 20, 21 that may be placed in direct or intimate engagement with internal heat exchange surfaces 22, 23 of the heat exchange discs 3, 4. The faces 20, 21, i.e. the major surface area portions of the discs as opposed to the relatively thin edges thereof, should be relatively large to provide a relatively large area of contact with the surfaces 22, 23 between which the medium 2 is effectively sandwiched. Internally the medium 2 should contain large surface areas for contact with the water flowing therethrough to optimize transfer of thermal energy therebetween. Furthermore, the medium 2 preferably has a substantial fluid dispersing characteristic capable of dispersing fluid flowing internally thereof for maximizing thermal energy transfer therewith, for avoiding stagnant flow areas therein, for minimizing channeling of fluid flowing therethrough, and for mixing fluid therein for uniformity of temperature and, accordingly, optimized thermal energy transfer; the thickness of the medium 2 in the net axial flow direction of the internal flow path 13 also should be selected to contribute positively to achievement of the foregoing. The medium 2 preferably is of circular plan, as shown, to avoid areas for fluid stagnation, for example in corners of a rectangular or similar shape medium. 
     According to the preferred embodiment and best mode, the heat transferring medium 2 is of mesh or mesh-like material, such as that of a metal filter, screen or the like. Such material provides the aforesaid characteristics, including those of fluid dispersion and mixing, large surface areas for heat transfer engagement with the fluid flowing therethrough and large faces 20, 21 for heat transfer engagement with the surfaces 22, 23 of the discs 3, 4. The mesh-like material of the heat transferring medium 2 may be compressed from a relaxed state between the discs 3, 4 and by the ring 5 such that faces 20, 21 become nearly integral, and, in any event, maintain good heat transfer conduction, with the surfaces 22, 23. The mesh medium 2 also may be compressed, as required, to fit snugly in the support ring 5 avoiding fluid flow at the effective interface between the medium and support ring and to provide, if desired, a fluid flow impedance and to optimize surface area exposure particularly to fluid flowing through the medium. Furthermore, to minimize the pressure drop of or flow impedance to fluid flowing through the heat transferring medium 2 and to avoid flow stagnation, it is preferred that the net open cross-sectional area integrated across a section of the medium 2 taken generally normal to the net internal flow path 13 therethrough is substantially constant in each of the media 2 employed in the heat exchanger 1 and, in fact, approximately equals the open cross-sectional area of the fluid inlet fitting 12 and fluid outlet fitting 14. 
     Each heat transferring medium 2 in combination with the respective adjacent relatively upstream and downstream heat exchange discs 3, 4 jointly form a sandwich like heat exchange unit 25 of which preferably there is a plurality thereof used in the heat exchanger 1. For example, the heat exchanger 1 may include thirty or more such heat exchange units 25. Preferably there is a heat exchange disc 4 adjacent the respective threaded inlet and outlet passages 26, 27 in the respective blocks 6, 7, and the remaining heat exchange discs 3, 4 employed in the heat exchanger 1 are shared in respectively adjacent heat exchange units 25. For example, the heat exchange disc 3 illustrated in FIG. 2 is employed as a part of the heat exchange unit 25 to the right thereof as well as of the heat exchange unit to the left thereof. The support rings 5 may be of rigid metal material, such as aluminum of cylindrical configuration to circumscribe the edge of respective heat transferring media 2 and with flat annular faces 28 that provide fluid-tight sealing engagement with respective surfaces of respective heat exchange plates 3, 4. The support ring 5 may be of a material that is a good thermal energy conductor further to enhance the conducting of thermal energy from the heating zone 10 into the area of the internal flow path 13. Further to maintain the fluid-tight integrity of the internal flow path 13, if desired, additional conventional anti-leakage means, such as caulking, elastomeric coatings, etc. may be employed at the junctures of discs 3, 4 with support rings 5; alternatively, the support rings themselves may be formed of anti-leakage material, such as relatively resilient material rather than rigid metal, plastic or the like. The support ring 5 may be eliminated if the heat transferring medium 2 has adequate strength for self-support under compression between respective discs 3, 4 and if preferably the outer cylindrical surface of the medium 2 is adequately fluid impermeable to avoid leakage thereat. The rods 8 and fasteners 9 are tightened relatively securely effectively clamping the heat exchange units 25 between the respective blocks 6, 7 to maintain the fluid-tight integrity of the internal flow path 13. A plurality of mounting rod holes 29 in the discs 3, 4 allow passage of the respective rods 8 therethrough. 
     The heat exchange discs 3, 4 provide fluid flow control functions. For example, the disc 3 has a plurality of fluid guiding openings 40 spaced in a circle radially about the approximate center of the disc 3 for receiving the fluid leaving the heat transferring medium 2&#39; upstream therefrom and dividing that fluid into a plurality of discrete flow streams which have a net directional flow along the axis 41 of the heat exchanger 1 and, thus, of the general internal flow path 13. Depending on the thickness of the disc 3, the openings 40 may provide for a turbulent-like mixing of the fluid entering the same from the medium 2 and a generally laminar flow directing of discrete streams formed by the respective openings into the downstream medium 2&#34;. The heat exchange disc 4 has a centrally located fluid guiding opening 42, which receives fluid from the medium 2&#34; collecting the same in a single stream and, depending on the thickness of the disc 4, allows mixing thereof, and further directs the single stream downstream into the heat transferring medium 2 of the next heat exchange unit 25 or in the case illustrated in FIG. 2 into the outlet passage 27 and outlet fitting 14 in the outlet block 7. 
     The heat exchange discs 3, 4 preferably are arranged in the heat exchanger 1 in an alternating pattern, as is shown in FIG. 1, and preferably, too, there will be a disc 4 at the opposite ends of the heat exchanger adjacent respective blocks 6, 7 so that the central openings 42 thereof can guide fluid with respect to the inlet and outlet passages 26, 27 and so that such end discs 4 complete respective heat exchange units 25 for optimum thermal energy transfer at the respective ends of the heat exchanger. Alternatively, if desired, the respective end heat exchange discs 4 may be eliminated, whereby the heat transferring medium 2 and support ring 5 associated therewith may be placed in abutment with respective blocks 6, 7. 
     In view of the foregoing, it will be clear that a substantial mixing of the fluid flowing through the internal flow path 13 will occur in the heat exchanger 1. In particular, fluid entering the heat exchanger 1 via the inlet fitting 12 and passage 26 passes through a center opening 42 in a heat exchange disc 4 adjacent the block 6. The fluid then is dispersed well in the first heat transferring medium 2 encountered. Fluid leaving the first heat transferring medium 2 is divided into multiple flow streams by the fluid guiding openings 40 in the next heat exchange disc 3, and the individual streams then enter the next downstream heat transferring medium 2, etc. As a result of the complexity of the internal flow path 13, the fluid flowing therethrough will thoroughly mix and will intimately engage with the large surface area exposure of the plural heat transferring media 2. Moreover, the flowing fluid will tend to come into some contact with the internal heat exchange surfaces 22, 23 of the respective discs 3, 4. The sizes of the openings 40, 42 in the discs 3, 4 may be selected, as desired, according to various parameters and constraints depending, for example, on viscosity of the fluid flowing therethrough, flow rates, pressure drops, mixing required, etc. However, in accordance with the preferred embodiment and best mode of the invention, in order to minimize pressure drop or flow impedance in the heat exchanger 1 while also optimizing mixing and heat transfer occurrence, the cross-sectional area of the fluid guiding opening 42 in each respective heat exchange disc 4, the sum of the cross-sectional areas of the plural fluid guiding openings 40 in each respective heat exchange disc 3, the open cross-sectional area of the respective inlet and outlet fittings 12, 14, and the net open cross-sectional area in the respective heat transferring media, as mentioned above, are the same. 
     In view of the foregoing, it will be clear that the intimate interengagement of fluid with exposed surface areas of the heat transferring media 2 as the former flows through the latter and is well mixed and thoroughly dispersed therein and guided by respective fluid guiding openings 40, 42 of heat exchange discs 3, 4, an effective transfer of thermal energy will occur between the fluid and the media 2. It is another principal function of the heat exchange discs 3, 4 to supply thermal energy to or to remove thermal energy from the respective heat transferring media 2. 
     Accordingly, in the preferred embodiment and best mode, the heat exchange discs 3, 4, which are fin-like in the conventional sense that they are exposed at the heating zone 10 to provide relatively large external heat exchange surfaces 43, 44, additionally provide a relatively low impedance heat flow path directly into the heat exchanger and, more particularly, to respective internal heat exchange surfaces 22, 23. Not only does the fluid in the internal flow path 13 directly encounter the internal heat exchange surfaces 22, 23, but also and more importantly such internal heat exchange surfaces provide thermal energy to the heat transferring media 2 with the latter providing an internal heat transfer surface comprised of the total surface area exposure thereof to the fluid in the internal flow path 13. Thus, the heat exchange discs 3, 4 provide the multiple functions of distributing fluid flowing through the internal flow path 13, holding the heat transfer media 2, providing sealing surfaces for the support rings 5, and transferring heat between multiple environments. Preferably each of the heat exchange discs 3, 4 is a single integral unit formed of a material that is a good thermal energy conductor, such as metal, which preferably is unaffected by the fluids to which it is exposed. The discs 3, 4 also preferably should be of relatively thin material for efficient rapid conduction and should be relatively strong to minimize undesired distortion. In the illustrated preferred embodiment of the invention, the discs 3, 4 are circular in plan view to facilitate placement of the entire heat exchanger 1 in a pipe. 
     In operation of the heat exchanger 1, fluid enters the same via the inlet fitting 12, flows through the same along the internal flow path 13 while mixing thoroughly being dispersed within the heat transferring media 2 and by the heat exchange discs 3, 4 and exits the same via the outlet fitting 14. In the meantime thermal energy is transferred with respect to the flowing fluid; particularly, in the preferred embodiment and best mode heat energy applied to the external heat exchange surfaces 43, 44 is conducted through the respective discs 3, 4 to the internal heat exchange surfaces 22, 23 for transferring with respect to the faces 20, 21 of the heat transferring media 2 for further transfer with respect to the fluid flowing therein. Moreover, on the whole, the mixing of fluid flowing through the internal flow path 13 is with a thoroughness comparable to that achieved in turbulent mixing but without requiring an input of energy needed for turbulent mixing and minimizing the pressure drop between the inlet and outlet fittings 12, 14 so that over-all the flow characteristic of the fluid is generally laminar, thus reducing energy input requirements of the heat exchanger 1 while obtaining efficient thermal energy transfer therein. 
     Due to the turbulence and mixing occurring in fluid flowing through the heat exchanger 1, the prior boundary layer insulation effects and the flow rate discrepancies between inner and outer portions of flow streams are reduced, thus increasing efficiency of thermal energy transfer. Moreover, by conducting thermal energy directly between the heating zone 10 and the internal flow path 13 via the heat exchange discs 3, 4, efficiency of thermal energy transfer is further improved over prior techniques. 
     An alternate embodiment of heat exchanger 1a is illustrated in FIG. 3 in which parts corresponding to those described above with reference to FIGS. 1 and 2 are identified by similar reference numerals with the suffix &#34;a&#34;. In the heat exchanger 1a there is an internal pipe 50 preferably located along the axis 41a of the heat exchanger. The pipe 50 passes through relatively tight fitting openings 51, 52 in the heat transferring media 2a and heat exchange discs 3a and through loose fitting openings 42a in the heat exchange discs 4a. The pipe 50 provides for a further isolated flow path inside the heat exchanger 1a supplemental to the internal flow path 13a, which provides, as above, fluid flow from an inlet fitting through respective heat exchange units 25a. The tight fitting openings 51, 52 assure fluid dispersion in the media 2a and developing of plural discrete flow streams by the openings 40a in the discs 3a and the loose fitting openings 42a pass the pipe and the fluid therethrough as part of the internal flow path 13a as above. 
     In the heat exchanger 1a the pipe 50 preferably is formed of copper or other metal or material that is unaffected by the fluids engaged therewith and that has a good thermal energy transfer characteristic. 
     In operation of the heat exchanger 1a, for example, a hot fluid may be directed through the pipe 50 from which thermal energy is transferred by conduction through the pipe to the heat transferring media 2a and to the heat transfer discs 3a for subsequent transfer with respect to the fluid flowing through the internal flow path 13a. Moreover, the fluid flow exiting the pipe 50, as represented by arrow 53, may be diverted back over the heat exchanger 1a through the external heating zone 10a to effect thermal energy transfer directly with respect to the external heat exchange surfaces 43a, 44a, as described above. 
     The heat exchanger 1a may be referred to as a so-called three pass system in which there are three separate fluid paths, namely that provided through the pipe 50, that provided in the external heating zone 10a, and that provided through the internal flow path 13a, the latter of which terminates through the outlet passage 27a in the end block 7a through an outlet fitting (not shown) that also accommodates isolated exiting therethrough of the pipe 50 via the arrow 53. In the preferred form of this alternate embodiment one fluid flows through the pipe 50 and past the external heating zone 10a while a second fluid flows through the internal flow path 13a; however, it will be appreciated that three isolated fluids may be used, namely one flowing through the pipe 50, one through the heating zone 10a, and one through the internal flow path 13a while all such fluids are maintained in fluidic isolation although also being in heat exchange relation with respect to each other. 
     In the alternate embodiment of heat exchanger 1b illustrated in FIG. 4, wherein parts similar to those described above with reference to FIGS. 1 and 2 are identified by the same reference numeral and the suffix &#34;b&#34;, the heat exchanger and, thus, the internal flow path represented by the arrow 13b therethrough are oriented vertically. The heating zone 10b has a tapered profile such that the diameters of the heat exchange discs 3b, 4b near one end of the heat exchanger 1b are of one size and those at the opposite end are of a different size with a gradual change occurring along the axial extent of the heat exchanger. Therefore, in the illustrated embodiment, if hot gases were delivered to the heating zone 10b near the bottom of the heat exchanger 1b, those gases would tend to rise and to expand while heating the continuously enlarging heat exchange discs 3b, 4b at the external heat exchange surfaces 43b, 44b thereof. In the illustrated embodiment of FIG. 4 the larger diameter discs are at the top of the heat exchanger 1b to accommodate the expanding hot gases whereby one disc will not totally block flow contact with the next disc; however, for cooling the internal fluid it will be appreciated that if a fluid that tends to drop, such as cold air, were applied to the upper part of the heating zone 10b, then the direction of taper thereof would be reversed, namely placing the smaller diameter discs near the top and the larger near the bottom thereof. 
     Referring now to FIGS. 5 and 6 in which the suffix &#34;c&#34; is used, as above, a further heat exchanger 1c in accordance with the invention is illustrated. A tube 60 between the blocks 6c, 7c isolates the heating zone 10c from the external environment of the heat exchanger 1c. For clarity of illustration, the tube 60 is not shown in FIG. 6. An inlet 61 supplies a fluid, such as the hot products of combustion, other hot gases, hot liquid, cold gases or liquid, etc. into the tube 60 and an outlet 62 exhausts the same. Moreover, preferably the tube 60 is relatively close fitting with respect to the outer edges of the respective heat exchange discs 3c, 4c and such discs are bent or distorted and have cut-outs 63, 64 in them to allow flow from an area near one disc to the next disc and so on and to direct a swirling or helical type flow through the heating zone 10c from the inlet 61 to the outlet 62. 
     Referring to FIG. 7, a top plan view schematically illustrates the askew cyclical orientation of the heat exchange discs 3d, 4d of a heat exchanger 1d to create a rotating flow of fluid through the heating zone 10d. In particular, the internal flow path 13d through the center of the heat exchanger 1d actually passes through sector areas of the heat exchange discs 3d, 4d rather than through the approximate centers thereof, and the discs are positioned in a pattern angularly displaced about the axis of the heat exchanger 1d generally to cause a rotating of the fluid flowing through the heating zone 10d of the heat exchanger vertically oriented in a manner similar to that illustrated in FIG. 4. Furthermore, if desired, the angularly displaced discs 3d, 4d also may be slightly deformed in a manner generally depicted in FIGS. 5 and 6 further to create the rotating flow pattern for gases flowing in the heating zone to accomplish a net axial flow thereof. 
     Turning now to FIG. 8, a heat exchanger 1e is schematically illustrated. In the heat exchanger 1e the heat exchange discs 3e, 4e need not extend diametrically beyond the support rings 5e of the heat transferring media 2e. A pipe or other elongate member 50e extends axially along the length of the heat exchanger 1e, and the internal flow path 13e, relative to the interference caused by the member 50e is similar to that described above reference to the internal flow path 13a in the heat exchanger 1a of FIG. 3. Thus, the member 50e passes through a relatively large loose fitting opening 42e in the disc 4e and similarly in the inlet and outlet blocks (not shown), and the member 50e passes in tight fitting relation through the openings 51e, 52e in the media 2e and discs 3e, respectively. The significant difference between the heat exchanger 1e and that described above with reference to FIG. 3 is that thermal energy input in the form of heat is applied via an electric heating element, such as an electric resistance element located in the member 50e or of which the member 50e forms a part. Such electric heating may be effected by a conventional electric resistance heating element energized from a conventional power supply via electrical leads 70, 71. Thus, the member 50e provides heat directly to the media 2e at the close fitting engagements therewith and directly to the discs 3e also at the close fitting engagements therewith for distribution by the latter about the respective media 2e. The discs 4e also further help to distribute uniformly thermal energy in the media 2e. Accordingly, it will be appreciated that the heating zone 10e of the heat exchanger 1e actually is internal of the latter. Moreover, if desired, the diameters of the discs 3e, 4e may be extended in order to provide external heating surfaces, such as those designated 43, 44 in the preferred embodiment of FIGS. 1 and 2, in order to provide additional thermal energy transfer surface areas with respect to an environment external of the heat exchanger 1e. 
     Another example of heat exchanger 1f in which thermal energy is supplied electrically is illustrated in FIG. 9. In the heat exchanger 1f, which is generally similar to the heat exchanger 1e, except that there need not be a member 50e internally located along the internal flow path thereof, a conventional electric heating coil 72 is wrapped about the cylindrical wall of the heat exchanger formed by the secured discs 3, 4 and support rings 5 between blocks 6f, 7f. The heating coil 72 may be energized from a conventional power supply via leads 70f, 71f to supply heat to the entire outer surface of the heat exchanger, including the outer edges of discs 3, 4 (not shown) and support rings 5 for transfer to the heat exchange media (not shown) internally of the heat exchanger. Moreover, a cover tube or enclosure 73 may be provided to concentrate the heat energy developed by the heating coil 72, to avoid dissipation of such heat energy away from the heat exchanger 1f, and, if desired, to provide electrical insulating characteristics for added safety of operation. 
     STATEMENT OF INDUSTRIAL APPLICATION 
     In view of the foregoing, it will be clear that the several embodiments of heat exchanger in accordance with the present invention may be employed to transfer thermal energy in an efficient manner. Such transfer may be between two or more fluids to heat or to cool one or more with respect to the other one or more, may be between a fluid and a solid, such as in the case of the electric input embodiments disclosed, etc. Moreover, it will be appreciated that the various features illustrated in the several figures may be interchanged and shared among the several embodiments disclosed; for example, electric heating may be included in the several non-electric heating embodiments, the additional internal isolated flow path of FIG. 3 may be included in the other embodiments, etc. 
     Several particular applications of the invention include use of the heat exchanger to cool the coolant in an automotive vehicle, to heat water in domestic and commercial environments, to control the temperature of materials in chemical processes, to provide a source of thermal energy for space heating and cooling, and so on.