Abstract:
Disclosed are systems and methods for generating power. The system includes a sealed chamber, a displacer located inside the chamber, a magnetic mechanism to actuate the displacer, and a linear alternator. The chamber includes a first side, a first top surface, and a first bottom surface, the first side located adjacent to a heat source and the second side adjacent to a heat sink. The displacer includes a pivot surface, a rocker, or a slide, and may include a regenerator.

Description:
FIELD OF INVENTION 
     The present disclosure relates to systems and methods for capturing energy from direct and waste thermal sources. More particularly, the present disclosure relates to systems and methods for producing electricity by extracting energy from hot gases such as exhaust gas generated by internal combustion engines and from solar concentrators. 
     BACKGROUND 
     Two major classes of engines are used to convert heat energy to mechanical energy and/or electrical energy—these being internal combustion (IC) and external combustion (EX) engines. Internal combustion engines dominate the transportation industry while the major applications of external combustion engines are found in the power generation industry where steam powered turbines are still a major application of the external combustion principle. 
     Stirling engines (SE) are external combustion engines with higher energy density than piston-based steam engines that may be as energetically efficient as internal combustion engines. Like steam power, SE&#39;s suffer relative to IC engines in having less dynamic power output; thus they are commonly found in applications where the power demand is relatively constant. The SE is a thermodynamic engine that delivers power by alternatively heating and cooling a fixed volume of gas with work being done by the pressure increase during the heating phase. A number of arrangements for achieving the alternate heating and cooling of the working fluid (i.e. a gas) have been developed, giving rise to three main forms of the engine (alpha, beta and gamma). In these traditional configurations and commercialized arrangements of a SE, the mechanical work is usually produced by the pressure of the heated gas acting on piston-crankshaft arrangements. The heat exchange surface is the surface of the cylinder(s) but mostly the cylinder head(s). Rotating SE&#39;s with crankshaft/piston designs require special seals, or provision to regenerate and recharge the working gas as it is lost through the joints provided for lubrication and power transfer. 
     SUMMARY 
     One aspect of the present disclosure relates to systems for generating electrical power by utilizing heat. Another aspect of the present disclosure relates to methods for generating electrical power by utilizing heat. 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter. Nor is this Summary intended to be used to limit the claimed subject matter&#39;s scope. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Non-limiting and non-exhaustive embodiments are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. 
         FIG. 1  is a diagram of a dual chamber engine for utilizing waste exhaust heat to generate electricity; 
         FIG. 2  is a flow chart of a cycle for utilizing waste heat to generate electricity with a two chambered engine; 
         FIG. 3  is a diagram of a single chamber engine for utilizing a heat source to generate electricity; 
         FIG. 4  is a flow chart of a cycle for utilizing heat with a single chamber engine to generate electricity; 
         FIG. 5  is a diagram of a second dual chamber engine for utilizing waste exhaust heat to generate electricity; 
         FIG. 6  is a flow chart of a cycle for utilizing waste heat to generate electricity; and 
         FIG. 7  is a diagram of an operative environment for an engine for utilizing waste exhaust heat to generate electricity. 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments are described more fully below with reference to the accompanying drawings, which form a part hereof, and which show specific embodiments of the invention. However, embodiments may be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Therefore, the following detailed description is not to be taken in a limiting sense. 
     Conceptually, one embodiment of the present disclosure is a non-cylindrical external combustion engine utilizing the Stirling cycle consisting of a flue (or plurality of flues) through which either the heating (hot combustion gases) or cooling (ambient air or water) fluid passes to respectively heat or cool the appropriate surface of chambers containing a displacer that may be positioned magnetically to expose the working fluid to either the heated or cooled surface. 
     Turning now to the figures,  FIG. 1  illustrates a section dual chamber engine  100  for utilizing gaseous heat (e.g. IC engine exhaust) to generate electricity. The dual chamber engine  100  includes two chambers  102  and  104  of any length, two baffles  106  and  108 , magnets  110  and  112 , and a linear alternator  114 . The chambers  102  and  104  are connected in fluid communication with one another via a conduit of the linear alternator  114 . In addition, passing between the chambers  102  and  104  is a heat source such as an exhaust conduit for conveying exhaust gas that is warmer than ambient air. In one embodiment, the conduit carries exhaust gas from an internal combustion engine such as a diesel engine or a spark ignition engine. The conduit can replace the exhaust pipe, muffler and catalytic converter allowing the capture of presently wasted energy. This capturing of otherwise wasted energy could lead to an increase in the energy efficiency of fossil fuel used. 
     Any heat source can be used to power the dual chamber engine  100 , particularly since the large heat exchange surface potential allows for efficient function when the temperature differential is low. The heat source may be solar radiation which can be concentrated onto a single side or onto both sides of an engine with the cooling flue being in the center. The heat exchange surface may include structures  136  for increasing surface area available for heat transfer such as fins, bumps, projections, curved surfaces, and other forms of extended surfaces. Moreover, regenerator assemblies may be located on surfaces in the chambers  102  and  104  in the path of displaced working gases to increase heat capture efficiency as the working fluid is moved by the articulated movement of the baffles  106  and  108 . The chambers  102 ,  104 , and flue  124  and the baffles  106  and  108  may be constructed from pressed/rolled metal welded at the seams to minimize gas leakage problems. 
     The chambers  102  and  104  have two opposing sides  126  and  128  that are identified as the heated and cooled surfaces, respectively. The power output of SE&#39;s is determined by the temperature difference between the internal heat exchange surfaces, the amount of gas displaced between the heated and cooled chambers, and the frequency of the cycle, the greatest efficiency of energy capture will be provided by a high exchange surface-chamber volume ratio which will maximize the cycle frequency. For instance a square tube of 2×2 cm has half the exchange surface area of a 4×1 cm tube while having the same volume of working gas. Sides  126  are heated by the heating medium and sides  128  are cooled by ambient air or other fluid cooler than the heat source. The simplest configuration would be a rectangular section tube but compound curves and corrugations are possible and may achieve savings of materials in manufacture. The material for construction of the chambers  102  and  104  may be non-magnetic within the vicinity of the magnet displacer drive to allow the action of the external magnets on the internal displacer. For example, the chambers  102  and  104  may be constructed from non-magnetic stainless steel, aluminum, or other materials that do not exhibit ferromagnetic properties such as plastics and ceramics. 
     The baffles  106  and  108  act as displacers to displace the working fluid in the chambers  102  and  104  thereby determining whether the working fluid is heated or cooled. Note that while  FIG. 1  depicts the baffles  106  and  108  having a rhombic shape, baffles  106  and  108  may be of differing shape such as, but not limited to, rectangular and various curved shapes to match surfaces  126  and  128 . For example, the outer and inner walls of the chambers  102  and  104  may have profiles to match the profile of the corresponding surface of the baffles  106  and  108 . In various aspects of the disclosure, the baffles  106  and  108  are configured such that during operation they pivot about points  116  and  118 , respectively. For example, the baffles  106  and  108  may be constructed such that at least a portion of the baffles  106  and  108  exhibit ferromagnetic properties (i.e. are attracted and/or repelled to poles of magnets) and magnets  110  and  112  may act on these ferromagnetic portions to cause the baffles  106  and  108  to pivot. Note that when the baffles  106  and  108  pivot, the working fluid flows from one side of the chambers  102  and  104 , respectively. In other words, as show in  FIG. 1 , the working fluid being heated and cooled are located on the left side of the chambers  104  and  106  respectively. When the baffles  106  and  108  pivot about points  116  and  118 , the working fluid will flow from the left sides of the chambers  102  and  104  to the right side of the chambers  102  and  104 . The operation of the dual chamber engine  100  will be described in greater detail below with respect to  FIG. 2 . In addition, the baffles  106  and  108  may be supplemented with one or more valves to assist in controlling the movement of the working fluid. 
     The magnets  110  and  112  may be fixed magnets or electromagnets. In addition, the magnets may be stationary or movable. For example, as shown in  FIG. 1 , the magnets  110  and  112  may be mounted to turntables  120  and  122  such that during operation the magnets  110  and  112  can change positions. The turntables  120  and  122  may be powered from electricity generated by the linear alternator  114 . In addition, when magnets  110  and  112  are electromagnets, they may receive power from the linear alternator  114  or any other source. Note that while  FIG. 1  shows only two magnets, any number of turntables and magnets may be used depending on the length and dimensions of the chambers. For example, magnets  110  and  112  may be electromagnets and two additional electromagnets  130  and  132  (represented by dashed lines) may be used control the movement of the baffles  106  and  108 . The operation of the dual chamber engine  100  with electromagnets will be described in greater detail below with respect to  FIG. 5 . 
     Turning now to  FIG. 2 ,  FIG. 2  is a flow chart setting forth the general stages of a cycle  200  for utilizing heat to generate electricity with the dual chamber engine  100 . The cycle  200  begins at stage  205  with the baffles  106  and  108  positioned so that as hot exhaust passes through the exhaust flue  124 , heat is transferred from the exhaust to a working gas located in the chamber  104 . While the gas in chamber  104  is being heated by the outer surface of the exhaust flue, the gas in chamber  102  is being cooled by contact to with surface  128  which is cooled to act as a heat sink. As the gas in the chamber  104  is heated by the hot exhaust, the gas expands. Simultaneously, the gas in chamber  102  contracts due to cooling. This combination of expansion/contraction causes the working gas to displace the piston of the linear alternator from chamber  104  towards chamber  102  causing a magnet  134  of the linear alternator to slide through or past coils in a direction  202  thereby generating electricity. Generally, a linear alternator generates an alternating electrical current (AC) by passing a reciprocating magnet in a linear direction through a coil of wires. Greater detail of the operation of a linear alternator can be found in U.S. Pat. Nos. 6,369,469, 5,180,939, 5,175,457, 5,146,123, 4,649,283, and 4,642,547, all of which are incorporated by reference in their entirety. 
     Once the magnet in the linear alternator  114  reaches a certain position, the cycle  200  proceeds to stage  210 . In stage  210 , the magnets  110  and  112  are repositioned to cause the baffles  106  and  108  to change positions as indicated by arrows  204  and  206 . While  FIG. 2  shows the magnets being repositioned, it should be understood that the magnets may be electromagnets and to change the baffles&#39;  106  and  108  positions, various magnets may be activated and deactivated, or their polarity reversed (See  FIG. 5 ). In other aspects of the disclosure, positioning of the baffles  106  and  108  may be controlled by sensors. The sensors may monitor the temperature differential, the pressure of the working fluid, or position of the linear alternator&#39;s  114  magnet. The sensors may receive power from the linear alternator  114  or any other source. 
     Once the baffles  106  and  108  have changed positions, the cycle  200  proceeds to stage  215 . In stage  215 , the hot exhaust in the exhaust flue  124  will heat the gas in the chamber  102 . As the gas in the chamber  102  absorbs heat, it will expand and drive the magnet(s) in the linear alternator in the direction of arrow  208  thereby generating AC electricity. 
     Once the magnet in the linear alternator  114  reaches a certain position the cycle  200  proceeds to stage  220 . In stage,  220  the magnets  110  and  112  are repositioned to cause the baffles  106  and  108  to change positions as indicated by arrows  212  and  214 . After the baffles  106  and  108  have changed positions, the cycle  200  proceeds to stage  205  where the cycle  200  begins again. 
       FIG. 3  is a diagram of a single chamber engine  300  for utilizing waste exhaust heat to generate electricity. The single chamber engine  300  includes a chamber  302 , a baffle,  306 , a magnet  310 , and a linear alternator  314 . On opposite sides of the chamber  302  is a heat source  324  (e.g., an exhaust conduit from an internal combustion engine) and cooling structure  326  (e.g., ambient air or another cooling fluid having a temperature lower than the fluid of the heat source). As stated above with regards to  FIG. 1 , regenerators and sensors may be used to increase heat conversion efficiencies and control positioning of the baffle  306 . 
     Note that while  FIGS. 1 and 3  depicts the baffle  106  and  306  having a triangular shape, the baffle  106  may be of differing shapes such as, but not limited to, rectangular and various curved shapes. In various aspects of the disclosure, the baffle  306  is configured such that during operation it pivots about point  316 . The operation of the single chamber engine  300  will be described in greater detail below with respect to  FIG. 4 . 
     As above with the dual chamber engine  100 , the magnet  310  may be a fixed magnet or one or more electromagnets. In addition, the magnets may be stationary or movable. For example, as show in  FIG. 3 , the magnet  310  may be mounted to a turntable  320  such that during operation the magnet  310  can change positions. In electromagnetic versions of the drive for the baffles this may be achieved by switching polarity of the magnet. 
     In various applications, including but not limited to, a solar application, electricity generated could be used for a home while water used for cooling would leave the system heated. This type of system could provide a dual value for homes and industry. In addition, two inline chambers could be utilized with the linear alternator  114  working at the junction. 
     Turning now to  FIG. 4 ,  FIG. 4  is a flow chart setting forth the general stages of a cycle  400  for utilizing waste heat to generate electricity. The cycle  400  begins at stage  405  with the baffle  306  positioned so that as a cooling fluid passes through the cooling chamber  326 , heat in the gas located in the chamber  302  is transferred to the cooling fluid. As the gas in the chamber  302  cools, a spring drives a magnet in the linear alternator  314  in the direction indicated by arrow  402 . 
     Once the magnet in the linear alternator  314  reaches a certain position the cycle  400  proceeds to stage  410 . In stage,  410  the magnet  310  is repositioned to cause the baffle  306  to change positions as indicated by arrow  404 . While  FIG. 4  shows the magnet  310  being repositioned, it should be understood that the magnet  310  may be an electromagnet and to change the baffle&#39;s  106  positions, various magnets may be activated and deactivated (See  FIG. 5 ). 
     Once the baffle  306  has changed positions, the cycle  400  proceeds to stage  415 . In stage  415 , the hot exhaust in the heat source  324  will heat the gas in the chamber  302 . As the gas in the chamber  302  absorbs waste heat, it will expand and drive the magnet in the linear alternator  314  in the direction of arrow  408  thereby generating AC electricity. 
     Once the magnet in the linear alternator  314  reaches a certain position the cycle  400  proceeds to stage  420 . In stage  420 , the magnet  310  is repositioned to cause the baffle  306  to change positions as indicated by arrow  412 . After the baffle  306  has changed positions, the cycle  400  proceeds to stage  405  where the cycle  400  begins again. 
       FIG. 5  illustrates a second dual chamber engine  500  for utilizing waste exhaust heat to generate electricity. The dual chamber engine  500  includes two chambers  502  and  504 , two slides  506  and  508 , magnets  510 ,  512 ,  526 , and  528 , and a linear alternator  514 . The chambers  502  and  504  are connected via the linear alternator  514 . In addition, passing between the chambers  502  and  504  is an exhaust conduit  524  (e.g. a flue). As stated above with regards to  FIG. 1 , regenerators and sensors may be used to increase heat transfer efficiencies and control positioning of the slides  506  and  508 . 
     In other embodiments, movement of the slides in a parallel action may be controlled by electromagnets or magnets on turntables. The turntables may be both above and below the chambers  502  and  504 . Also note that there are a variety of displacer configurations. Non-limiting example include a pivoted rectangular displacer inside a V-shaped chamber, and a pie-slice shaped displacer in a rectangular sectioned chamber where the movement is not a pivot but a rocking action. 
     Note that while  FIG. 5  depicts the slides  506  and  508  having a rectangular shape, the slides  506  and  508  may be of differing shape such as, but not limited to, various curved shapes. As described above with respect to  FIG. 1  when the slides  506  and  508  change position, the working fluid flows from one side of the chambers  502  and  504 , respectively. The magnets  510 ,  512 ,  526 , and  528  are electromagnets. In addition, the magnets  510 ,  512 ,  526 , and  528  may be stationary or movable. The operation of the dual chamber engine  500  will be described in greater detail below with respect to  FIG. 2 . 
     The operation of the dual chamber engine  500  may be described with reference to  FIG. 6 . The cycle  600  begins at stage  605  with the slides  106  and  108  positioned so that as hot exhaust passes through the exhaust conduit  524 , heat is transferred from the exhaust to a gas located in the chamber  504 . While the gas in chamber  504  is being heated by the exhaust, the gas in chamber  502  is being cooled. As the gas in the chamber  504  is heated by the hot exhaust, the gas expands. Simultaneously, the gas in chamber  502  contracts due to cooling. This combination of expansion/contraction causes the working fluid to flow through the linear alternator from chamber  504  to chamber  502  causing a magnet  534  of the linear alternator  514  to slide toward chamber  502  in a direction  602  thereby generating electricity. 
     Once the magnet in the linear alternator  514  reaches a certain position, the cycle  600  proceeds to stage  610 . In stage  610 , the electromagnets  510  and  512  de-energize or change polarity and the electromagnets  526  and  528  energize to cause the slides  506  and  508  to change positions as indicated by arrows  604  and  606 . In other aspects of the disclosure, positioning of the baffles  106  and  108  may be controlled by sensors. The sensors monitor the pressure of the working fluid, or position of the linear alternator&#39;s  514  magnet  534 . The sensors may receive power from the linear alternator  514 . 
     Once the slides  506  and  508  have changed positions, the cycle  600  proceeds to stage  615 . In stage  615 , the hot exhaust in the exhaust conduit  524  will heat the gas in the chamber  502 , while the working fluid in chamber  504  looses heat and contracts. As the gas in the chamber  502  absorbs waste heat, it will expand and drive the magnet  534  in the linear alternator  514  in the direction of arrow  608  thereby generating AC electricity. 
     Once the magnet  534  in the linear alternator  514  reaches a certain position the cycle  600  proceeds to stage  620 . In stage,  620  the electromagnets  526  and  528  de-energize and the electromagnets  510  and  512  energize to cause the slides  506  and  508  to change positions as indicated by arrows  612  and  614 . After the slides  506  and  508  have changed positions, the cycle  600  proceeds to stage  605  where the cycle  600  begins again. 
     For example, the cycle  600  begins at stage  605  with the slides  506  and  508  positioned so that as hot exhaust passes through the exhaust conduit  524 , heat is transferred from the exhaust to a gas located in the chamber  504 . While the exhaust is heating the gas in the chamber  504 , the gas in the chamber  502  is being cooled. As the gas in the chamber  504  receives heat from the hot exhaust, working fluid (e.g. air) flow from the chamber being heated to the chamber being cooled causes a magnet located in the linear alternator  514  to move in the direction of arrow  202  and generate electricity. 
     Once the magnet in the linear alternator  514  reaches a certain position the cycle  600  proceeds to stage  610 . In stage  610 , the magnets  510  and  512  are deactivated and the magnates  526  and  528  are activated to cause the slides  506  and  508  to change positions as indicated by arrows  604  and  606 . 
     Once the slides  506  and  508  have changed positions, the cycle  600  proceeds to stage  615 . In stage  615 , the hot exhaust in the exhaust conduit  524  will heat the gas in the chamber  502 . As the gas in the chamber  502  absorbs waste heat, it will expand and drive the magnet in the linear alternator  514  in the direction of arrow  608  thereby generating AC electricity. 
     Once the magnet in the linear alternator  514  reaches a certain position the cycle  600  proceeds to stage  620 . In stage  620 , the magnets  510  and  512  activate and the magnets  526  and  528  deactivate to cause the slides  506  and  508  to traverse the chambers  502  and  504 , respectively, as indicated by arrows  612  and  614 . After the slides  506  and  508  have changed positions, the cycle  600  proceeds to stage  605  where the cycle  600  begins again. 
       FIG. 7  shows an operating environment for the dual chamber engine  100 . The setup shown in  FIG. 7  includes four dual chamber engines  100  arranged in line. Examples of the operating environment include, but are not limited to, an automobile exhaust system, exhaust system of internal combustion engines, cooling systems, etc. For example, when the dual chamber engine  100  is used as the exhaust system of an internal combustion engine  706 , the hot working fluid may flow through flue  124  as indicated by arrow  704 . In other aspects of the disclosure, coolant from an automobile engine may flow from the automobile&#39;s engine through heat sink exchange surfaces associated with each engine  100  to dissipate heat before flowing to the automobile&#39;s radiator, or some dedicated heat exchange/cooling arrangement. 
     Another example of an operating environment may include an exhaust system. For this environment, an array of the dual chamber engines  100  may act as flues with catalytic materials or catalytic cores in the flue  124  to form a power generating catalytic converter for vehicles with internal combustion engines. For example, catalytic materials may include, but are not limited to platinum, palladium, rhodium, cerium, iron, manganese, copper, and nickel. In addition, the use of sound absorbing materials may be attached to spacers (upper side and lower side of  124  ( 125 , and  127 ) forming the flue  124  of the dual chamber engines  100  to form the exhaust pipe and thus forming a power generating muffler. For example, the dual chamber engine  100  can be incorporated along the length of an exhaust system of an engine (e.g., along exhaust piping such as a tail pipe, catalytic converter housing, diesel particulate filter housing, muffler bodies or other components of an exhaust system). The engine can be a stationary engine or an engine on a vehicle. 
     In another operating environment, the dual or single chamber engine  100  may be used with solar concentrators. The solar concentrators may concentrate solar energy onto surface  128  to heat the fluids in chambers  102  and  104 . A cooling fluid (e.g., water or air) may be used to dissipate heat via surfaces  126 . 
     In addition, multiple chambers may drive a single linear alternator. In other words, the heat exchange surface may be very large so the linear alternator output is maximized. In other embodiments a large heat exchange surface area may allow the system to work with a small temperature differential. In yet other embodiments, a flue with multiple single or dual chamber engines  100  (e.g. a 2×2 chamber) so that all internal surfaces are providing for energy capture. 
     Reference may be made throughout this specification to “one embodiment,” “an embodiment,” “embodiments,” “an aspect,” or “aspects” meaning that a particular described feature, structure, or characteristic may be included in at least one embodiment of the present invention. Thus, usage of such phrases may refer to more than just one embodiment or aspect. In addition, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments or aspects. Furthermore, reference to a single item may mean a single item or a plurality of items, just as reference to a plurality of items may mean a single item. Moreover, use of the term “and” when incorporated into a list is intended to imply that all the elements of the list, a single item of the list, or any combination of items in the list has been contemplated. 
     One skilled in the relevant art may recognize, however, that the invention may be practiced without one or more of the specific details, or with other methods, resources, materials, etc. In other instances, well known structures, resources, or operations have not been shown or described in detail merely to avoid obscuring aspects of the invention. 
     While example embodiments and applications of the present invention have been illustrated and described, it is to be understood that the invention is not limited to the precise configuration and resources described above. Various modifications, changes, and variations apparent to those skilled in the art may be made in the arrangement, operation, and details of the methods and systems of the present invention disclosed herein without departing from the scope of the claimed invention. 
     The above specification, examples, and data provide a description of the manufacture, operation and use of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.