Patent Publication Number: US-6983105-B1

Title: Waste energy recovery system, method of recovering waste energy from fluids, pipes having thermally interrupted sections, and devices for maximizing operational characteristics and minimizing space requirements

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application is a continuation-in-part of U.S. patent application Ser. No. 10/461,363, filed Jun. 16, 2003, now U.S. Pat. No. 6,823,135, issued Nov. 23, 2004, and which is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The invention relates to waste energy recovery systems. More particularly, the invention relates to systems which recover “waste” or excess heat from energy systems, such as cooling water systems and power plants, engine cooling radiator systems in automobiles, and the like. Even more particularly, the invention relates to fluid transfer devices such as pipes, which pipes are subdivided into thermally interrupted sections so that the amount of heat transfer from one fluid to another fluid is maximized, thereby maximizing the amount of energy recovery, and devices enhancing the maximizing of energy recovery, while minimizing space requirements. 
   BACKGROUND OF THE INVENTION 
   Systems are known for using heated fluid to transfer heat from one source to another. For example, heated water is used in diesel fuel furnace heated radiator systems, such as hot water radiator systems in houses, to transfer heat from the heater or furnace to a closed loop fluid system, which in turn, transfers heat to heated water for household radiators or consumption. 
   Other fluid heat transfer systems are known, such as used in power plants, automobile engine applications, and the like. 
   Examples of known systems include those set forth in the following U.S. Pat. Nos.
         4,080,181 to Feistel et al.   4,168,743 to Arai et al.   4,217,954 to Vincent   5,694,515 to Goswami et al.   4,852,645 to Coulon et al.   4,949,781 to Porowski   5,211,220 to Swozil et al.       

   OBJECTS AND SUMMARY OF THE INVENTION 
   An object of the invention is to overcome the drawbacks of the prior art. 
   Another object of the invention is to maximize heat transfer between two (2) bodies; e.g., between a first fluid and a second fluid. 
   A further object of the invention is to provide only one significant “pathway” along which heat may flow, so as to maximize the efficiency of the heat exchanger. 
   Yet another object of the invention is to provide a fluid transfer device, such as a pipe of any size or shape, which is divided into segments, adjacent segments of which are thermally insulated or isolated from adjacent segments, so that, heat transfer may be maximized within, and out of, each isolated segment, while minimizing heat transfer between adjacent segments. 
   Yet another object of the invention is to provide a device, system, and method for recovering so-called “waste” energy in industrial and residential applications so that such waste energy may be utilized in order to conserve natural resources, as well as to reduce costs. 
   Another object of invention is to provide a system for maximizing heat transfer applicable in all industries, residential applications, boiler systems, power plants, cryogenic (liquid gas process) systems, radiators, air conditioners, and refrigeration systems, for example. 
   A still further object of the invention is to optimize the temperature of the fluid within an isolated zone or segment for maximizing the temperature difference between adjacent isolated (or thermally insulated) segments and between an adjacent body or bodies to which the heat is to be transferred. 
   A further object of the invention is to reduce the length of known heat exchangers. 
   A further object of the invention is to achieve higher temperatures in a heat transfer systems, such as conduits containing a heated fluid, such higher temperatures achieving greater and more efficient heat transfer between such conduits and the object to be heated. 
   Another object of the invention is to provide a heat exchanger applicable to tube-in-tube, tube-in-shell, and flat plate heat exchangers, as well as solar collectors, countercurrent flow heat exchangers, and parallel flow heat exchangers. 
   Another object of the invention is to provide a heat exchanger system applicable to solid, liquid, and gaseous heat exchangers, usable for both heating and cooling purposes. 
   Yet another object of the invention is to ensure that the maximum thermal exchange occurs in each zone between the zone and an adjacent object, such as a countercurrent fluid flow or a solid, with which adjacent object heat transfer occurs. 
   Another object of the invention is to optimize countercurrent flow rates and volumes depending on the heat capacity of the respective materials for optimizing heat transfer. 
   A yet still further object of the invention is to provide a substantially flat heat exchanger, which maximizes the surface area between the flows, which maximizes heat transfer in the desired direction and to the desired body, i.e., object or fluid, to be heated. 
   Another object is to provide a heat exchanger having thermally isolated sections that is compact, e.g., it achieves the required heat transfer rates and temperature gradients of longer systems. 
   A further object of the invention is to provide a heat exchanger having thermally isolated sections that includes a modular construction, and which modular construction may include detachably attached sections. 
   A further object of the invention is to provide a heat exchanger having thinner walls than prior art systems, yet which heat exchanger is able to operate at higher pressures than known heat exchangers. 
   Yet another object of the invention is to provide a heat exchanger having a large surface area to volume construction, and, as needed, using one or more webs in the fluid flow path to enhance the fluid flow, increase the temperature differentials attained, strengthen the thin-walled configuration, or any combination of the three. 
   Another object of the invention is to provide stronger joints between adjacent zones in heat exchangers, while minimizing the overlap of conductive material from one zone into adjacent zone(s). 
   Yet another object of the invention is to strengthen the joints between adjacent zones, while improving the alignment of the fluid flow paths in adjacent zones to ensure that the desired fluid flow operating characteristics are maintained, while reducing the time required to join together adjacent zones through such joints. 
   A still further object of the invention is to provide a heat exchanger having readily removable zones or fluid flow sections to enhance the ease of maintenance of the system and/or to enhance the ease of modifying the system, such as readily expanding the system. 
   Another object of the invention is to reduce or eliminate undesirable static build up on a surface area of a heat exchanger, such as by grounding one or more portions of the heat exchanger. 
   Another object of the invention is to provide a heat exchanger having a relatively large surface area configured and suited for being used as one or both of a chemical and a biological reaction zone, such zones may be coated with a catalyst to enhance a chemical or biological reaction, and separate, isolated (e.g. parallel) fluid flows may merge into a reaction zone to bring chemical or biological reactants into the respective chemical or biological reaction zones. 
   Yet another object of the invention is to provide a heat exchanger in which the heat exchange zone is configured for attaining specific thermodynamic needs, such as eliminating the problem of icing in air conditioning (AC) systems, such as by configuring the expansion of the zone in stages to reduce zones which may lead to such AC icing, for example. 
   Yet another object of the invention is to provide a heat exchanger configured for relatively fast heating or cooling of a fluid thanks to the provision of a low flow volume to large surface area heat exchange system. 
   Another object of the invention is to provide an isolated zone heat exchange system configured to function as a (at least) temporary thermal storage system, such as by the provision of a thermal storage mass in each of one or more zones (to increase the thermal storage capacity of the zones), as well as to thermally isolate the inflow and outflow from the system to reduce undesirable thermal pathways which may reduce the efficiency of the thermal storage system. 
   Yet another object of the invention is to configure and connect thermally isolated zones in a progressive S-fashion, such as by the use of a cross current design using pipes isolated during a change in fluid flow direction, and that itself may be an example of using a relatively long zone connected to an adjacent zone with thermally isolating material located at a point at which the fluid flow direction is changed. 
   Another object of the invention is to provide a solar collector with thermally isolated zones to enhance the efficiency thereof. 
   Yet another object of the invention is to provide a thermally isolated zone heat transfer system provided with a device for cleaning the fluid pathways of the system, such as by reducing or removing condensation, reducing or eliminating the need for cooling fins, and the like. 
   Another object of the invention is to provide a thermally isolated heat transfer system suited for aggressive environments, such system being provided with a corrosion resistant finish suited for a particular environment. 
   Another object of the invention is to provide a heat exchanger including spaced apart plate-like walls, the spaced opposed plate-like walls being configured to hold respective positive and negative charges, the spacing, positive, and the negative charges being selected, configured, and sufficient to establish electrical charges to separate respective negatively and positively charged constituents of a compound passed through the first fluid transfer section, in use. 
   Yet another object of the invention is to provide a finish on a thermally isolated heat transfer system that reduces the frictional coefficient of the fluid transfer device in which the fluid is flowing so as to enhance the fluid flow and make the fluid flow more consistent and, hence, easier to fine tune and maximize the desired fluid flow characteristics. 
   Another object of the invention is to provide thinner walls in the fluid transfer devices of a heat exchanger system than known devices while operating at higher pressures, such being achieved by the provision of, for example, adjacent fluid pathways being operated at substantially the same fluid pressure for reducing pressure differentials and, hence, providing for such higher operating pressures with thinner walls being achieved. 
   Another object of the invention is to provide one or more plenums at one or both of an inlet and an outlet of a fluid heat transfer system, such plenum(s) enhancing the fluid flow characteristics such as evening out and modulating the fluid flow. 
   Yet another object of the invention is to provide a heat transfer system, such as an isolated zone heat exchanger, that is contained substantially within a low pressure insulating container (i.e. a “vacuum”-type container). 
   Another object of the invention is to provide one or more flow modifiers to increase or reduce laminar flow through a zone, depending on the configuration, mass flow rate, and the like of the fluid passing through the zone, so as to increase the flow of fluid and increase the rate of heat transfer/temperature gradient in the desired direction and/or to induce radial flow patterns or turbulence in the fluid. 
   In summary, the invention is directed to a waste energy recovery system including a heat exchanger having a first fluid transfer device and a second fluid transfer device. The first fluid transfer device has an inlet and an outlet, and is configured for carrying a heated fluid from its inlet to its outlet. The second fluid transfer device has an inlet and an outlet and is configured for carrying an unheated fluid from its inlet to its outlet. The first fluid transfer device may be provided with two(2) fluid transfer sections, each such section being connected and separated by an insulating or isolating connector disposed therebetween. The insulating connector has greater insulating characteristics than at least one of the two fluid transfer sections. 
   The invention likewise is directed to a method of using the inventive waste energy recovery system for recovering waste energy. 
   In addition, the invention is directed to the novel components, such as the fluid transfer device being subdivided into two or more fluid transfer sections, adjacent ones of the fluid transfer sections being connected by respective insulating connectors so that heat transfer is minimized along the length of the fluid transfer device, while heat transfer is maximized out of and away from each thus isolated fluid transfer section to a respective body or bodies to be heated (or cooled). 
   It will be seen that the invention has achieved at least the above-described objects, as set forth in detail above and below. 
   It will be understood that relative terms such as up, down, left, and right are for convenience only and are not intended to be limiting. 
   It should likewise be understood that the fluid transfer device is not intended to be limited to engine manifolds, flash steam conduits formed in furnaces of power plants, pipes, tubes or the like, yet includes any device which conveys a gas, liquid, semi-solid, or solid from one location to another for transferring heat from such a conveyed fluid or solid. The terms insulated and isolated are intended to be used interchangeably, the term isolated emphasizing that the insulated fluid transfer section of a fluid transfer device, for example, is thermally isolated (insulated) from adjacent fluid transfer section(s). 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic sectional view of an embodiment of a heat transfer device  10  according to the invention that maximizes the temperature gradient along its length as well as relative to the environment in which it is located in order to maximize heat transfer between it and its environment or between it and another object in thermal contact with heat transfer device  10 ; 
       FIG. 2  is a schematic sectional view of another embodiment of a heat transfer device according to the invention. 
       FIG. 3  is a schematic sectional view of another heat transfer device according to the invention in which multiple heat transfer devices in the form of integrally attached plate-like tubes are disposed adjacent to each other; 
       FIG. 4  is perspective view of a further heat transfer device according to the invention in which multiple heat transfer devices in the form of pipes or tubes are disposed in a common pipe or tube, which common pipe or tube may be insulated; 
       FIG. 5  is a sectional view taken along line  5 — 5  of  FIG. 6  of an embodiment of a heat exchanger according to the invention; 
       FIG. 6  is sectional view taken along line  6 — 6  of the embodiment of  FIG. 5 ; 
       FIG. 7  is a front perspective view of an insulated segment of the heat transfer device of  FIG. 5 ; 
       FIG. 8  is a rear perspective view of an insulated segment of the heat transfer device of  FIG. 5 ; 
       FIG. 9  is a schematic sectional view of a heat transfer device according to the invention, particularly suited for use in a flattened form; 
       FIG. 10  is another embodiment of a heat transfer device according to the invention, usable as a waste energy recovery or “instant” hot water heater; 
       FIG. 11  is a further embodiment of a heat transfer device usable as an “instant” hot water heater, for example, in which an electric heater element is analogous to the coiled, fluid-carrying tube of the  FIG. 10  embodiments; 
       FIG. 12  is a sectional view taken along line  12 — 12  of  FIG. 13  of another heat transfer device according to the invention; 
       FIG. 13  is a sectional view taken along line  13 — 13  of the embodiment of  FIG. 12 ; 
       FIG. 14  is a front perspective view of another embodiment of an insulated segment according to the invention including a snap-fit connector, shown in a manner similar to  FIG. 5 ; 
       FIG. 15  is an end view of the insulated segment of  FIG. 14 ; 
       FIG. 16  is an end view of another embodiment of an insulated segment of a heat transfer device according to the invention having a groove to enhance the attachment thereof; 
       FIG. 17  is a partially cut away front perspective view of the embodiment of  FIG. 16 ; 
       FIG. 18  is a partially cut away top perspective view of another embodiment of fluid transfer sections including flow-directing webs according to the invention; 
       FIG. 19  is an upper front perspective view of another embodiment of a fluid transfer section that has oppositely charged upper and lower side walls; 
       FIG. 20  is a partially broken away perspective view of another embodiment of an insulated fluid transfer device, including an ultrasound generator according to the invention; and 
       FIG. 21  is a schematic side view of another embodiment of a fluid transfer device according to the invention incorporating a plenum for directing, controlling and modifying fluid flow within respective flow passages. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  illustrates a heat transfer device  10  according to the invention. 
   Fundamentally, heat transfer device  10  maximizes heat transfer between a fluid and an adjacent body, such as the environment, or a further unillustrated heat transfer device  10  by maximizing a temperature gradient both along its length  12  and between the adjacent body (or environment) along sections of the heat transfer device  10 . 
   Heat transfer device  10  may include an inlet  14  and an outlet  18 , defined by a wall  30 , and one or more heat transfer sections  32 ,  34 , and  36 . 
   A heated or unheated fluid hotter or colder than the environment may flow from inlet  14  to outlet  18  depending on whether or not the fluid is to be cooled or heated (or whether the environment is to be heated or cooled), depending on the intended use (or the perspective one takes). 
   Good results have been achieved when an insulating or isolating connector is disposed between one or more heat transfer sections; e.g., an insulating segment  56  between heat transfer sections or segments  32  and  34 , and an insulating segment  58  between heat transfer sections  34  and  36 . The material of respective insulating segments  56 ,  58  may be selected so that the insulating segment  56 , for example, has greater resistance to heat transfer than one or both of adjacent heat transfer sections  32  and  34 . In that manner, section  32  is thermally insulated or isolated from section  34 . Good results have been achieved when the insulating characteristics of segment  56  are selected so that heat transfer along length  12  of the transfer device  10 , e.g., between individual sections  32  and  34 , for example, is minimized. 
   As heat is transferred from (or to) another body or the environment, as shown by heat transfer arrows  62 ,  64 , and  66 , such heat transfer is maximized thanks to minimizing heat transfer  68  and  70  along the length  12  of device  10  from one fluid section  32 ,  34 ,  36  to another. Thus, the temperature drop (i.e., outlet temperature relative to inlet temperature) of a fluid flowing into device  10  at  74  and out at  78  is maximized, and overall heat transfer to another body as shown by heat transfer arrows  62 ,  64 , and  66  is maximized. The heat transfer along length  12  from segments  32  to segment  34  and from segment  34  to segment  36  is minimized and concurrently, heat transfer “outwardly” away from device  10  to an adjacent body or the environment as represented by heat transfer arrows  62 ,  64 , and  66  is maximized, thus the temperature gradient or “drop” of the mass of fluid flowing from inlet  74  to outlet  78  is maximized. 
   Device  10  may be termed an isolated zone heat exchanger thanks to its use of segments  32 ,  34 , and  36  thermally isolated from each other by respective isolating segments  56  and  58 . 
   If isolation segments  56  and  58  were not present as is the case in prior art devices, heat would be more readily transferred from segment  32  to segment  34  than is the case in inventive device  10 , and the thus transferred heat would be transferred, in turn, to the fluid flowing in segment  34 . Thus, the temperature gradient along length  12  would be less than is the case in device  10 , and consequently, less thermal transfer would occur between device  10  and an adjacent body or the environment. 
   Heat transfer device  10  may be termed a radiator, as device  10  is suited for use in warming its environment in the case where a fluid, for example, hotter than the ambient temperature of the environment is introduced into inlet  14 , flows in direction  74  while radiating heat outwardly as shown by arrow  62 ,  64 , and  66 , as described above, and then exits at outlet  78 . It will be readily appreciated that fluid introduced into inlet  14  that is colder than the environment would cool the environment thanks to heat being radiated from the environment to the colder fluid and the desired cooling effect would be achieved. 
     FIG. 2  illustrates another heat transfer device in the form of an isolated zone heat exchanger  80 , for example, suited for transferring heat from one fluid to another, such as for recovering undesired or “waste” heat in a power plant or from the heated water of a water-cooled engine. 
   Heat exchanger may include heat transfer device  10  divided into isolated sections  32 ,  34 , and so forth defined by respective isolating segments  56 ,  58 , and so forth. 
   A first fluid H may flow into heat exchanger  80  in direction  74  and out of device  10  in direction  78 . Countercurrent or counterflow of a second fluid C, to which heat from the first fluid H is transferred, flows through heat exchanger  80  in a direction going from an inlet  84  to an outlet  88 . 
   Heat exchanger  80  may be disposed within an insulated shell  100  including insulated walls  102  and  104 . A shell made of metal and other thermally conductive material may encase the insulated shell  100 , depending on the intended use. 
   Consideration of a possible use of heat exchanger  80  will enhance understanding of the temperature gradients and heat exchange maximized in heat exchanger  80 . For discussion purposes, a fluid H flowing in direction  74  may be considered a hot or heated fluid and a fluid C flowing in direction  84  may be considered a cold or cooled fluid. Namely, fluid H may be considered hotter than fluid C for the discussion below. 
   Hot fluid H flows into thermally isolated section  32  and radiates heat away from section  32  in the direction of arrow  62 . More particularly, heat from flow H 1  is conducted or transferred to section  32 , which in turn conducts or transfers heat to fluid C 4  in the direction of arrow  62 . Little heat is transferred along the length of wall  30  of device  10  from section  32  to section  34 , owing to the insulating quality of insulating segment  56  which interrupts wall  30  along its length. The heat is radiated outwardly from region H 1 , or exchanged with a region C 4 , in its associated fluid-filled region defined by shell  100 . Fluid H 1  in that portion of flowing fluid H transfers heat to a quantity of fluid C 4  of fluid C flowing within shell  100 . Fluid portion C 4  cools fluid portion H 1 . The temperatures of fluid H and C in a fluid region adjacent isolating segment  56  will be ignored for ease of discussion. 
   In the next heat exchanging region in section  34 , a fluid portion H 2  exchanges heat with an adjacent fluid portion C 3 , fluid portion C 3  cooling fluid portion H 2 , and portion H 2  heating fluid portion C 3 . Further along the path of travel of fluid H and a fluid portion H 3 , and a fluid portion C 2  heat and cool each other respectively. Still further along, a fluid portion H 4  and a fluid portion C 1  respectively heat and cool each other. 
   By maximizing the thermal gradient along the length  82  of heat exchanger  80 , temperature transfer (heat transfer) is maximized between the adjacent regions and overall temperature transfer (heat transfer) is maximized. 
     FIG. 3  illustrates another embodiment of a heat exchanger  140  having isolated zones or sections, similar to the heat exchanger  80  of  FIG. 2 , yet with a wall or array  144  being provided that may include one or more common walls  146 ,  148  and  152 . Common walls  146  and so forth, facilitate heat transfer between the fluid in adjacent regions or zones of fluids of differing temperatures. The operation may be carried out in substantially the same fashion as the operation of the isolated zone heat exchanger described herein. 
     FIG. 4  illustrates another embodiment of an isolated zone heat exchanger  200  according to the invention. 
   Isolated zone heat exchanger  200  may include a wall  202 , which may be insulated depending on the intended use, and a plurality of individual isolated zone heat exchangers  10 , as described above. 
   A heated fluid may be introduced into exchanger  10  in the direction of arrow  74 , and exited in the direction of arrow  78 , such introduction of fluid being done in one or more heat exchangers  10 . Likewise, a colder or cooled fluid  84  may be introduced in the direction of arrow  84 , and exited in the direction of arrow  88 . In the case where the fluid introduced at  74  is hotter than the fluid exiting at  88 , the fluid within heat exchangers  10  will heat up the fluid found within the shell or outer tube defined by wall  202 . Alternatively, a relatively hot fluid could be introduced at  84  for heating relatively cold fluid introduced into one or more heated exchangers  10 . 
     FIGS. 5–8  illustrate another embodiment of an isolated zone heat exchanger  250  having a housing or shell  270  configured for enclosing a typically counterflowing fluid and the space defined between an isolated zone heat exchanger disposed within shell  270 . 
   Heat exchanger  290  may include heat conductive segments  272  and  274 , for example, each of which defines a fluid conduit  280  therein. 
   One or more respective thermally isolating segments  288  may be provided between adjacent sections  272 ,  274 , and so forth. 
     FIGS. 7 and 8  illustrate perspective views of isolated section  272  of exchanger  290  having a male coupling  276  and a respective mating female coupling  278 . One or more fluid conduits  280  and  282  may be provided. 
   Fluid conduits  280  and  282  may be substantially flat for increasing the surface to volume ratio of the conduits for enhancing thermal transfer between a fluid provided therein and the defining section  272 , and hence, enhancing heat transfer to a counterflowing fluid outside of section  272  to which the heat is to be transferred. For example, thermal energy of a heated fluid introduced at  74  into substantially flat tubes  280  and  282  may thus be readily transferred to other fluid introduced at  84  and flowing past isolated section  272 . The temperature of a fluid introduced at  74  may be greater than the temperature of a fluid introduced at  84 , thereby resulting in heat transfer from fluid at  74  to fluid exiting at  88 , and heat transfer between cooled heated fluid exiting at  78  and unheated cooler fluid introduced at  84 . Depending on the intended use of isolated zone heat exchangers  250 , a fluid introduced at  74  may be initially cooler than a fluid introduced at  84 , whereby a greater quantity of thermal energy is transferred from the fluid introduced at  84  to the fluid introduced at  74 , so that fluid introduced at  84  heats up the fluid introduced at  74 . 
   An isolating or insulating layer of material  288  may be provided on the female end, as shown, or on the male end, or on both the female and male ends. 
   In use, thanks to male coupling  276  and female coupling  278 , and the isolating segment  288 , individual segments  290  may be readily joined together to form an isolated zone heat exchanger. A suitable adhesive or other fastening means may be provided between adjacent segments during assembly of the individual segments  272 ,  274 , with or without a fluid type seal depending on the intended use. 
     FIG. 9  illustrates another embodiment of an isolated zone heat exchanger  320  according to the invention, which may likewise be provided with an array  340  of thermally isolated and segmented fluid conduits, isolated by the provision of thermal insulators  356 ,  358 , and so forth. 
   A housing or shell  330 , which may be insulated, may likewise be provided that defines a space between shell  330  and the array  340  of heat exchangers, which space receives the fluid introduced in direction  84 . As in previous embodiments, a further counterflowing fluid is introduced at  74  so that it may be heated or cooled by the fluid introduced at  84 . 
     FIG. 10  illustrates another embodiment of an isolated zone heat exchanger  380  which may be used as a so-called “instant” hot water heater, for example. 
   Instant hot water heater  380  will be discussed taking the point of view that a heated fluid may be introduced in the direction of arrow  74  into an at least partially coiled tube  382  including coils  384 ,  386 ,  388 ,  394 ,  396 ,  398 , and so forth. 
   A respective isolating or insulating segment  402  and  404  may be provided between respective groups of coils  406  or  408 , for example. 
   The coiled tube  382  may be provided around heat exchanger  10 , as described above. Coiled tube  382  may have a substantially flat (e.g., rectangular, thin-walled) configuration to maximize the fluid flow in “contact” with the surface of the pipe carrying fluid to be heated that is introduced at  84 . The configuration of the conduit carrying fluid to be heated may likewise be varied to maximize the amount of contact area of the wall of the conduit in contact with pipe  382  and, hence, in “contact” with the fluid introduced at  74 . 
   For ease of discussion, it will be assumed that a heated fluid will be introduced into coiled tube  382 , which heated fluid has been heated by an on-demand heater or furnace, such as a natural gas burner. In such a case, coiled tube  382  may be considered the heating tube or heating coil which heats heat exchanger  10 , and hence, the fluid in exchanger  10 . 
   Tube  382  may be part of a closed loop system. 
   In the case where the heated water is for human consumption, such as for heating water to be used in a residential kitchen, the fluid introduced at  84  may be drinkable water. 
   Thanks to the temperature gradient achieved between the fluid introduced at  74  cooled along its path of travel, and exiting at  78 , heat exchange will be efficient and rapid. The cooling of the fluid in coiled tube  382  corresponds to the desired heating of the water in heat exchanger  10 , along the lines described. 
     FIG. 11  illustrates a further preferred embodiment of a heat exchanger  420  according to the invention. In heat exchanger  420 , an electric coil  422  has been used as a heat source for heating a fluid introduced at  84  into isolated zone heat exchanger  10 . 
   A series of coils  430 ,  432 ,  434 ,  436 , and  438  is provided in a first group of coils  440  (5 coils total, for example), four (4) heating coils are provided in a grouping  450 , and three heating coils are provided in a grouping  460 . These groupings  440 ,  450 ,  460  have been selected to illustrate the assumption that each electrically heated coil  430 ,  432 , and so forth, of electric heating element  422  is heated an equal amount when electricity flows. This assumption is for ease of discussion. Different fluids and heating coil properties will require variation readily determined, in practice. 
   Likewise, the unheated or coldest fluid is introduced at  84 , and the heated hottest fluid is exited at  88 . By providing five electric heating coils in group  440 , the isolated segment  36  is provided with a relatively large thermal gradient. 
   Further, the provision of four coils in grouping  450  in isolated segment  34  having the less heated fluid  84  therein maintains a large gradient between the less heated fluid, and the three heating coils in grouping  460  provide less overall heat, yet the fluid introduced at  84  in isolated segment  32  is least heated in segment  32  and, hence, the temperature gradient between the electrical coil grouping  460  and the initially unheated fluid is still maximized. 
   It will be appreciated that there will be cooling of the heated heating coils groupings  440 ,  450 , and  460 , just as there is cooling of the groupings of fluid-filled coils  406  and  408  in the  FIG. 10  embodiment. 
   A plug  470  for plugging heater  420  into an electrical outlet may be provided, as well as a control C for controlling operation as will be readily understood as such controls C are available or readily constructed with conventional components. 
   In both the instant hot water heater of embodiment  420  of  FIG. 11  and the instant hot water heater  380  of  FIG. 10 , the size, number, and spacing of the respective heating coils and groupings will be varied depending on the requirements and intended use. 
   A dryer, such as for drying clothes, could be made more energy efficient by using so-called waste energy (i.e., energy not used for the drying process) to heat the fluid used in the drying process. For example, a conventional electric clothes dryer in which the heated air used for drying wet clothes is heated by an electric heater and heated moist exhaust air vented from the dryer and typically exited to the atmosphere may have its energy efficiency enhanced as follows. One could use one or both of the embodiments of  FIGS. 10 and 11  to enhance the operation of the clothes dryer by scavenging waste energy from the vent pipe carrying moisture-laden heated air and using the scavenged or recovered waste heat to heat the incoming fluid in the form of dry air to be heated. In such a case, one may consider the heat exchanger  380  of  FIG. 10  as representative of the dryer exhaust pipe and the electrically heated fluid heat exchanger  420  of  FIG. 11  to be the apparatus with which one will heat the dry air to provide heated dry air to the dryer for drying clothes therein. The embodiment of  FIG. 10  may be used in addition to the embodiment of  FIG. 11  to supplement the heat provided by the  FIG. 11  embodiment for heating the incoming air to be heated. If the  FIG. 10  embodiment is used instead of the  FIG. 11  embodiment for heating incoming air a conventional air heating device may be used to heat incoming air that has been modified to account for the lower heating requirement necessary thanks to the waste heat being recovered by the heat exchanger of  FIG. 10  supplementing the modified conventional heating apparatus for heating incoming air. 
   In a commercial setting, such as in a laundromat with multiple dryers, the waste heat from multiple dryers may be recovered to supplement or completely replace the heat required to heat incoming air in one of the number of dryers. For example, if 10 dryers are in use, 9 or 10 of the dryers may be provided with the heat exchanger of  380  of  FIG. 10  and provide enough recovered waste heat from the moisture-laden vented exhaust air to provide all the heat required to heat the incoming unheated dry air of the 10 th  dryer, for example. That is merely an example of a use to which the embodiments of  FIGS. 10 and 11  may be put. 
     FIGS. 12 and 13  illustrate a further preferred embodiment of a heat exchanger  550  according to the invention. 
     FIGS. 12 and 13  illustrate another embodiment of an isolated zone heat exchanger  550  having a housing or shell  570  configured for enclosing a typically counterflowing fluid and the space defined between an isolated zone heat exchanger disposed within shell  570 . 
   Heat exchanger  590  may include heat conductive segments  572  and  574 , for example, each of which defines a fluid conduit  580  therein. 
   One or more respective thermally isolating segments  598  may be provided between adjacent sections  572 ,  574 , and so forth. 
   One or more heating elements  606 ,  608  may be provided that may be electric and controlled by a control C 1  readily constructed to yield the desired features. 
   Heating elements  606 ,  608  and associated conduit  580  may be substantially flat for increasing the surface to volume ratio of the conduits for enhancing thermal transfer between heating elements  606 ,  608  and the defining section  572 ,  574  and hence, enhancing heat transfer to a counterflowing fluid outside of section  572 ,  574  to which the heat is to be transferred. For example, thermal energy of heated elements  606 ,  608  may thus be readily transferred to fluid introduced at  584  and flowing past isolated sections  572 ,  574  for example. The temperature of heating elements  606 ,  608  may be greater than the temperature of a fluid introduced at  584 , thereby resulting in heat transfer from heating elements  606 ,  608  to fluid exiting at  588 . Depending on the intended use of isolated zone heat exchangers  550 , the size and the configuration of elements  606 ,  608 , an isolating or insulating layer of material  588  may be provided on the female end, as shown, or on the male end, or on both the female and male ends. 
     FIGS. 14 and 15  illustrate another embodiment of an individual modular segment  650  of an isolated zone heat exchanger that is similar to the embodiments of  FIGS. 5–8 . 
   Modular segments  650  may be readily joined together to form an isolated zone heat exchanger, along the lines described above. 
   In this embodiment, segment  650  may include a male coupling  676  having a male element  682  of a snap-fit connector. Typically on an opposite end of segment  650  a mating female coupling  690  having a groove  692  may be provided. Groove  692  may be configured to mate with protrusion  682  for establishing a readily attachable and detachable snap-connector. One or more fluid conduits  684  and  686  may be provided. A thermally isolating portion  688  may be provided, the function of which has been explained in detail in connection with other embodiments. 
   The mating connector elements  682  and  692  may be sized and configured to ensure that mating individual segments  650  are sufficiently securely held together in use, depending on the intended use. 
     FIGS. 16 and 17  illustrate yet another embodiment of a modular segment  700  according to the invention. 
   Modular segment  700  may include a substantially flat end face  710 , a fluid conduit  714 , and a groove  716 . 
   In use, groove  716  may mate with a corresponding male extension configured to sufficiently securely locate the segment  700  to an adjacent segment. It is contemplated that grooves  716  be provided on both ends of segment  700 , and that a further element, such as a ring or glue be provided in the respective mated grooves  716 . Depending on the intended use, an adhesive selected for the conditions contemplated during use may be provided on one or both of face  710  and groove  716 . 
     FIG. 18  illustrates another embodiment of a portion or segment  750  of a heat exchanger according to the invention. Portion  750  may likewise be made as a modular segment including a thermally conductive end  754  and a one or more insulating segments  760 . In this embodiment, one or more webs  772 ,  774 , and  776  may be provided to divide a fluid flow  780  into multiple flow paths. Webs  772 ,  774  and  776  may be configured to establish laminar or turbulent flow, depending on the intended use. 
     FIG. 19  illustrates another embodiment of the invention in which a segment  800  may be provided with an electrically charged or chargeable upper plate or wall  810  and a lower electrically chargeable or charged plate or wall  820 . 
   Segment  800  is particularly suited for the separation of compounds, such as positively and negatively charged compounds or elemental portions of such compounds. For example, segment  800  may be used for the separation of water (H 2 O) into its elemental constituents hydrogen (H 2 ) and oxygen (O 2 ). Upper plate  810  may be positively charged, as indicated by positive charges  812 , and lower plate or wall  820  may be negatively charged, as indicated by negative charges  824 . As shown, it is contemplated that upper and lower plates  810  and  820  may be coated with respective coatings to retain such positive and negative charges. 
   In addition, it is contemplated that plates  810  and  820  may comprise a respective electrophorus or electrect, by which is meant charged bodies which maintain there respective positive or negative charges over time. In such a case, a dividing wall  830  which maintains the separation between the already separated particles or constituents need not be an insulator. 
   In the case where an electrical input is used to establish one or both of the positive and negative charges on walls  810  and  820 , it is contemplated that a user may provide dividing wall  830  as an electrical insulator which substantially completely, if not completely, electrically isolates the positively charged plate  810  from the negatively charged plate  820 , as will be readily appreciated. 
   As shown, in use, a compound or mixture of compounds may be introduced in a direction  840 , negatively charged portions or compounds of a mixture of compounds will be attracted to positively charged plate  810 , and positively charged constituents will be attracted to negatively charged plate  820 . The flow rate and configuration of the segment  800  may be selected so that divided flow  844  comprises substantially negatively charged elements or compounds, depending on the use, and the other divided flow  848  comprises substantially only negatively charged compounds of the divided compound or group of compounds introduced in direction  840 . 
     FIG. 20  illustrates another embodiment of a heat exchanger  900  according to the invention. 
   Heat exchanger  900  may include a modular segment  910  having one or more of walls  912  defining a fluid conduit  914  therein. 
   An insulator  916  may be provided between adjacent segments  910  for thermally isolating one segment from another, the benefits of which are detailed above. 
   An ultrasonic generator may be provided for actuating a transducer  924  operatively connected thereto by an appropriate electrical connection  926 . Ultrasonic transducer  924  may be used for converting electrical energy to mechanical energy and, hence, to wave energy in the ultrasonic frequency range. The ultrasound generated may be selected for ensuring that the fluid flow path defined by fluid conduit  914  remains sufficiently clean to establish and maintain the desired heat transfer characteristics from the fluid or into the fluid, depending on the intended use. 
   In addition, an external insulated housing  950  including one or more walls  952  may be provided that establishes a space  954  between outer walls of a segment  910  and housing  950 . The space  954  may be sufficiently pressurized (depressurized) to establish a substantially lower pressure so as to establish a near “vacuum”. As will be readily appreciated, such a near vacuum has excellent insulating characteristics owing to the near absence of a thermally conductive fluid, such as atmospheric air, therein. Housing  950  may include a thermal insulator depending on the intended use. In order to provide additional support and a desired spacing between housing  950  and segment  910 , one or more supports may be provided extending between outer wall  912  and wall  952 , such as by providing one or more extensions extending outwardly away from insulated portion  916 . By providing such support or extensions at insulated portion  916 , less undesirable heat transfer occurs, than if support were made directly to a thermally conductive wall  912 . 
     FIG. 21  illustrates a heat exchange system  1000  according to the invention that may be provided with a plenum indicated generally in a region  1004 . 
   System  1000  may be provided with an insulating or isolating portion  1010  between one or more walls  1012 , as in other ones of the embodiments according to the invention. Such walls  1012  define flow paths into which a first flow  1014  and a second flow  1018 . Depending on the intended use, one or more opposite fluid flows will be introduced in adjacent fluid paths as indicated by arrows  1022  and  1024 . Plenum  1004  may be configured so as to turn and to redirect the fluid flow as shown by arrow  1026  and  1028 . The redirecting of the fluid flow may be for establishing or reestablishing laminar flow, turbulent flow, radial flow or other flow patterns, depending on the intended use. Likewise, respective fluid flows  1014  and  1018  may have their flow paths redirected as shown by arrows  1032  and  1034 , respectively. 
   It is contemplated that multiple plenums  1004  having the same or different configurations be used. 
   In the case where insulator  1010  is provided in a central portion, as shown, a wall  1042  may be an insulator and serve as an outer shell of a heat exchanger. Depending on the intended use, the outer two flow paths  1022  and  1024  may be provided adjacent a thermally conductive wall  1042 , in which case insulator  1010  may be extended into and thermally isolate a left portion of wall  1042  from a right portion of wall  1042 , as will be readily appreciated. 
   The use of plenum  1004  increases the efficiency of the system and ensures that heat exchanger system  1000  may be made as compact and efficient as possible. It is further contemplated that particular flow patterns will be established at the respective inlets and outlets. 
   It will be appreciated that temperature measuring devices, thermal mass flowmeters, and the like may be provided at the inlets or outlets, and automatic controls may be provided to ensure that the efficiency of the system shown in  FIG. 21  is maximized, as well as in the other embodiments of the invention. 
   In any of the above-described embodiments, and consistent with the invention, the use of uninsulated versus insulated housings, the use or non-use of housings, the number of counterflowing fluid paths, the configuration and cross-sectional areas of fluid paths, and all other features may be varied, added or subtracted, depending on the intended use. 
   For ease of discussion, given that such will be readily apparent to a person having ordinary skill in the art, discussion of heat/mass transfer rates, conductivity, fluid flow rates, and so forth, have been minimized. It will be appreciated that the choice of heating/cooling fluids, with or without additives, the varying of fluid flow rates, mass flow rates, and the selection of thermal conductivity parameters of the devices defining the fluid path and those of adjacent counterflowing fluid paths, may be varied depending on the intended use, and are within the scope of a person having ordinary skill in the art. 
   It is likewise contemplated that the size, material, insulating properties, and configuration of the insulating segments, the conduits or the tubes, the housing, the fluid flow path, and the like, may be varied depending on the intended use. It is contemplated that the conductive fluid pathway when formed as tubes may include tubes of the same size, or different sizes with insulating material provided in between tube joints of any type. 
   Parallel flow in addition to or instead of countercurrent flow systems may be used. 
   Better results have been achieved by use of thermally conductive fluid-filled tube, such as a metal tube with an isolated segment disposed and thermally isolating adjacent sections of the metal tube, as compared with a metal tube of the same length and flow volume having no thermally isolated section isolated by isolating segments. A greater temperature difference between the inlet and outlet of the tube having the thermally isolating segment, as compared with the inlet and outlet temperature difference of the metal tube having no thermally isolated segment, has been demonstrated. 
   It will be appreciated that any of the materials of the tubes, conduits, pipes, isolating segments, shells, housing, and so forth may be varied depending on the intended use, the variation including but not limited to various metals such as steel, cast iron, copper, stainless steel, ceramics, and so forth. The insulating material of the isolating segments may be any of a variety of sufficiently thermally isolating materials to achieve a desired temperature gradient depending on the intended use, including but not limited to epoxies, plastics, synthetic materials, rubber, ceramics, and so forth. 
   While this invention has been described as having a preferred design, it is understood that it is capable of further modifications, and uses and/or adaptations of the invention and following in general the principle of the invention and including such departures from the present disclosure as come within the known or customary practice in the art to which the invention pertains, and as may be applied to the central features hereinbefore set forth, and fall within the scope of the invention or limits of the claims appended hereto.