Abstract:
An apparatus and method for generating electricity are disclosed. A ferroliquid having magnetic dipoles is confined in a conduit which is endless and can have a spiral configuration. The conduit has an electric coil wrapped around it. A temperature difference and a first magnetic field are applied to the liquid, thereby both moving and aligning the dipoles of the ferroliquid. The aligned dipoles create a second magnetic field which interacts with the coil to generate an emf therein.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to the generation of electricity and, in particular, by the conversion of thermal energy into electrical energy making use of a liquid which includes particles having a magnetic dipole. 
         [0002]    Over the years many proposals have been put forward to provide electric generators of various kinds. The following patents are representative of this art, namely U.S. Pat. Nos. 4,064,409, 5,632,093, 6,489,694, 6,504,271, 6,628,017, 6,982,501, 7,061,129, 7,095,143, 7,105,935 and 7,745,962. 
         [0003]    There is a need for improved methods and apparatuses for generating electricity that overcome deficiencies of the prior art. 
       SUMMARY OF THE INVENTION 
       [0004]    In accordance with a first aspect of the present invention there is disclosed a method of generating electricity, said method comprising the steps of: confining a liquid including particles having a magnetic dipole to a conduit formed into an endless loop, winding a coil around at least a portion of said conduit, exposing said conduit to a temperature difference to establish a convective flow in said liquid through said conduit, and exposing said liquid to a first magnetic field to align said particles whilst within said magnetic field, wherein a second magnetic field produced by said aligned dipoles moves relative to said coil to thereby generate an electromotive force (hereafter “emf”) therein. 
         [0005]    In accordance with a second aspect of the present invention there is disclosed an apparatus for generating electricity, said apparatus comprising a conduit formed into an endless loop and confining a liquid including particles having a magnetic dipole, a coil wound around at least a portion of said conduit, heat transfer means connected with said conduit to establish a temperature difference in said conduit which establishes a convective flow in said liquid through said conduit, and a pair of magnetic poles between which extends a first magnetic field to which said liquid is exposed to align said particles whilst within said magnetic field, whereby a second magnetic field produced by said aligned dipoles moves relative to said coil to thereby generate an emf therein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0006]    The present invention will hereinafter be described in conjunction with the appended drawing figures wherein like numerals denote like elements. 
           [0007]      FIG. 1  is a perspective view of a generator apparatus in accordance with an embodiment of the present invention; 
           [0008]      FIG. 2  is a cross-sectional view taken along the line II-II of  FIG. 1  and showing a first form of a conduit; 
           [0009]      FIG. 3  is a cross-sectional view taken along the line III-III of  FIG. 1  and showing a second form of a conduit; 
           [0010]      FIG. 4  is a perspective view illustrating the winding of a coil around a conduit in accordance with an embodiment of the present invention; 
           [0011]      FIG. 5  is a cross-sectional view through the upper portion of the generator of  FIG. 1  taken along the line IV-IV of  FIG. 1 ; 
           [0012]      FIG. 6  is a perspective view of the generator of  FIG. 1  showing an arrangement of permanent magnets in accordance with an embodiment of the present invention; 
           [0013]      FIG. 7  is a circuit diagram illustrating the electrical connection of the coil of  FIG. 1 ; 
           [0014]      FIG. 8  is a cross-sectional view of the conduit of  FIG. 9  taken along the line V-V of  FIG. 9  illustrating an alternative arrangement for a conduit including thermally conductive portions in accordance with an embodiment of the present invention; 
           [0015]      FIG. 9  is a perspective view of the conduit illustrated in  FIG. 8 ; 
           [0016]      FIG. 10  is a perspective view of a generator in accordance with another embodiment of the present invention; 
           [0017]      FIG. 11  is a perspective view illustrating another alternative arrangement for a conduit in accordance with another embodiment of the present invention; 
           [0018]      FIG. 12  is a perspective view of a generator in accordance with another embodiment of the present invention; 
           [0019]      FIG. 13  is a cross-sectional view of the generator of  FIG. 12  taken along the line VI-VI of  FIG. 12 ; 
           [0020]      FIG. 14  is a cross-sectional view similar to  FIG. 13  but of a generator in accordance with another embodiment of the present invention; 
           [0021]      FIG. 15  is a plan view of a generator in accordance with another embodiment of the present invention; 
           [0022]      FIG. 16  is a perspective view of the generator of  FIG. 15 ; 
           [0023]      FIG. 17  is a perspective view of a generator incorporating a gnomic spiral in accordance with another embodiment of the present invention; 
           [0024]      FIG. 18  is drawing of a gnomic spiral of the type utilized in the generator of  FIG. 17 ; 
           [0025]      FIG. 19  illustrates a mathematical formula for a gnomic surface; and 
           [0026]      FIG. 20  is a perspective view of a generator in accordance with another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]    The ensuing detailed description provides preferred exemplary embodiments only, and is not intended to limit the scope, applicability, or configuration of the invention. Rather, the ensuing detailed description of the preferred exemplary embodiments will provide those skilled in the art with an enabling description for implementing the preferred exemplary embodiments of the invention. It being understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the invention, as set forth in the appended claims. In addition, reference numerals that are introduced in the specification in association with a drawing figure may be repeated in one or more subsequent figures without additional description in the specification in order to provide context for other features. 
         [0028]    As seen in  FIG. 1 , a generator  1  takes the form of a cone shaped thermal conductor  2 . Wrapped around the cone shaped thermal conductor  2  is a conduit  3  which is non-conducting and which is configured into a conical spiral as illustrated. 
         [0029]    The cone shaped thermal conductor  2  is supported by a thermally conductive disc  5  which is supported by a thermally conductive stem  6  which terminates in a thermally conductive plate  7  that is in thermal communication with earth  8  (or a different heat sink). 
         [0030]    Located exterior of the conduit  3  is a second cone shaped thermal conductor  12  which is only shown in fragmentary form in  FIG. 1 . Intermediate the conductors  2 ,  12  the conduit  3  has a coil  13  formed from insulated electrical wire which is wrapped around the conduit  3 . The coil  13  can be spiral, helical, solenoidal or helicoidal. The coil  13  is connected to a volt meter  14 . 
         [0031]    In addition, the conduit  3  passes through a thermally conductive sleeve  16  which is thermally connected to a heat exchanger  17 . The heat exchanger is exposed to solar radiation (or some other heat source such as industrial waste heat, a geothermal heat source, or the like). 
         [0032]    As seen in  FIG. 2 , the conduit  3  preferably has a flattened surface  31  which lies against the interior cone shaped thermal conductor  2  thereby increasing the thermal transfer without impeding flow of liquid through the conduit  3 . 
         [0033]    Alternatively, as seen in  FIGS. 3 and 4 , the conduit  3  can be provided with a circular cross-section which can either be constant or varying along its length. 
         [0034]    As seen in  FIG. 5 , it will be apparent that the conduit  3  is in thermal contact with the thermally conductive disc  5  which is cold relative to the heat exchanger  17  and thermally conductive sleeve  16 . As a consequence, the liquid (not illustrated) within the conduit  3  is subjected to a temperature difference which establishes a convective flow of the liquid through the conduit  3 . 
         [0035]    As seen in  FIG. 6 , the thermally conductive stem  6  preferably extends to the top of the cone shaped thermal conductor  2  and supports same. In addition, the thermally conductive stem  6  also supports of stack of annular permanent magnets  20  having polarities as indicated in the drawing. A plurality of conducting plates  21  are attached to thermally conductive stem  6  and separate each of the plurality of annular permanent magnets  20  in the stack. 
         [0036]    The fluid confined within the conduit  3  contains small particles, each of which has a magnetic dipole. One form of such particles is powdered iron oxide, for example, magnetite. It will be apparent to those skilled in the art that the paramagnetic magnetite becomes magnetised with magnetic dipoles being created due to the magnetic fields created by the permanent magnets  21  so as to align the dipoles within the conduit  3 . This alignment of the dipoles, together with the thermally induced motion of the liquid, means that the magnetic field of the dipoles is cutting the turns of the coil  13  (i.e., the magnetic field of the dipoles of the magnetite particles moves relative to the coils and exposes the coils to a varying magnetic field) and thereby generates (i.e., via induction) an emf in the coil  13  which registers as a voltage on the voltmeter  14 . In this connection it will be observed that the path travelled by the magnetic dipoles is both curved and the radius of curvature of the curved path continuously changes. 
         [0037]    Turning now to  FIGS. 8 and 9 , an alternative conduit  103  is illustrated having two strips  104  of thermally and electrically conductive material such as copper interspaced with strips  105  of insulating material such as rubber or plastic. The conductive strips  104  maximise the transfer of heat into and from the conduit  103 . 
         [0038]    Turning now to  FIG. 10 , an alternative form of a transfer mechanism is illustrated in which a heat exchanger  47  confines a liquid  48  which is heated by solar radiation incident upon the heat exchanger  47 . The return path of the conduit  103  lies within the heat exchanger  47 . The thermally conductive stem  6  is surrounded by a cylindrical housing  49  upon which the conduit  103  is coiled and which contains a liquid  50  which is in thermal communication with the thermally conductive stem  6  and therefore the earth  8  (illustrated in  FIG. 1 ). 
         [0039]    In  FIG. 11  an alternative heat exchanger arrangement for a conduit  203  is illustrated. The conduit  203  is not thermally conductive but has two thermally conductive portions  204 ,  205  which are respectively connected to the heat exchanger  17  and a heat sink  208  which can include a tank of water, for example, or the earth  8  as illustrated in  FIG. 1 . The two thermally conductive portions  204 ,  205  are constructed so as to have an internal surface which is flush with the internal surface of the conduit  203  so as to thereby ensure a smooth flow of the fluid having the magnetic dipoles. 
         [0040]    Turning now to  FIGS. 12 and 13 , a duplicated arrangement is illustrated with two heat sources  417  and two heat sinks  419 . The heat sinks are in thermal communication with two cone shaped thermal conductors  402  each of which has a corresponding conduit  403 . Each conduit  403  spirals through the interior of the cone shaped thermal conductors  402  and then passes between the heat sources  417  and the cone shaped thermal conductors  402 . 
         [0041]    Furthermore, as illustrated in  FIG. 14 , a four spiral arrangement generator is illustrated in which like parts to the arrangement illustrated in  FIGS. 12 and 13  have the same designation numbers in  FIG. 14 . In  FIG. 14  preferably additional magnets  421  are placed exterior to the heat source  417 . 
         [0042]    As seen in  FIGS. 15 and 16  a conduit  503  having a generally spiral shape but a closed path extends vertically between a pair of horizontally spaced permanent magnets  521 . Two sleeves  516  and two heat exchangers  517  enable a convective flow of liquid within the conduit  503  to be established. As before a coil  513  is wound on the conduit  503  and terminates in a meter  514 . 
         [0043]    The operation of the generator of  FIGS. 15 and 16  is substantially the same as that described above save that the geometry of the conduit  503  is different from that of the conduit  3 ,  103 ,  203 . In addition, instead of the magnets  521  giving a magnetic field with a generally horizontal alignment, a vertically aligned magnetic field as indicated by broken lines in  FIG. 16  can be used. 
         [0044]    Turning now to  FIG. 17 , another embodiment is illustrated in which a hollow ovoid  601  contains the working liquid. An annular plate  609  is positioned near the top of the hollow ovoid  601  and has a central aperture  629  and a plurality of regularly spaced apart holes  639 . The central aperture  629  is the upper opening of a generally vertically arranged gnomic spiral conduit  603  which has an exit aperture  649 . 
         [0045]    As before a coil  613  is wound on the conduit  603 , terminates in a meter  614  and is located in a generally horizontal magnet field which extends between a pair of permanent magnets  621 . Located at the bottom of the hollow ovoid  601  is a heat source  617  and located at the top of the ovoid is a heat sink  619 . The difference in temperature between the heat source  617  and heat sink  619  sets up a convective flow. The upwards convective flow is illustrated by solid arrows in  FIG. 17  and flows upwardly through the regularly spaced apart holes  639 . Thereafter, the liquid cooled by the heat sink  619  falls into the central aperture  629  and thereafter spirals downwardly through the conduit  603  as indicated by broken line arrows in  FIG. 17 . 
         [0046]    The conduit  603  is preferably a portion of a gnomic spiral known to mathematics and to biology in the formation of marine sea shells, for example. A typical form of such a gnomic spiral is illustrated in  FIG. 18 . A mathematical formula for a gnomic surface is given in  FIG. 19 . Useful surfaces are generated where the constant A is greater than zero but less than 1. The vector r(θ,0) is the shape of the generating curve which is assumed to lie in the X-Z plane whilst the matrix corresponds to a simple rotation through the angle φ measured about the Z axis. The conduit  603  of  FIG. 17  is a truncated and inverted form of the spiral illustrated in  FIG. 18 . 
         [0047]      FIG. 20  illustrates yet another generator similar to that of  FIG. 17  save that the hollow ovoid  701  has an interior lining  750  of diamagnetic bismuth (except opposite the magnets  721 ) and the conduit  703  has an elliptical horn shape about which the coil  713  is wound. The fluid moves in curved paths indicated by the arrows in  FIG. 20 . 
         [0048]    It will be apparent to those skilled in the art that the generators of  FIG. 17  can be inverted and the roles of the heat source and heat sink reversed, in which case the upwards convective flow through the conduit  603  is indicated by broken arrows in the inverted  FIG. 17 . 
         [0049]    To summarise, disclosed are a number of preferred features and concepts for generating electricity in accordance with embodiments of the present invention, including: 1) a temperature differential to drive via convective flow a fluid comprised of particles which have magnetised magnetic dipoles coated with a surfactant and suspended in a carrier fluid or a paramagnetic fluid comprised of particles which have dipoles that become magnetic under the influence of an external magnetic field; 2) a vessel (or conduit in some of the embodiments) comprised of any continuously-varying curved surface to influence the flow and acceleration of the particles of the fluid (the surface is a conduit in some embodiments and a continuously curved shape in others that facilitates the helicoidal movement of the fluid); 3) a coil to, in response to the flow of the particles of the fluid, generate an emf in an external circuit; 4) a magnetic field comprised of the earth&#39;s magnetic field and/or an auxiliary magnetic field preferably created by at least one pair of magnetic poles placed in vicinity of apparatus; and 5) a diamagnetic material used on surfaces near flowing fluid or in fluid. 
         [0050]    The foregoing describes only some embodiments of the present invention and modifications, obvious to those skilled in the electric generator arts, can be made thereto without departing from the scope of the present invention. 
         [0051]    For example, the heat exchanger  17  can constitute a conventional solar hot water heater. Similarly, instead of magnetite, the ferrofluid can contain or comprise paramagnetic iron chloride or iron sulphate. 
         [0052]    The term “comprising” (and its grammatical variations) as used herein is used in the inclusive sense of “including” or “having” and not in the exclusive sense of “consisting only of”.