Abstract:
Apparatus and process for generating an electric output comprising (a) electromagnetic means having magnet means and electromagnetic coil means; (i) a plurality of gas receiving chambers comprising at least a first chamber and a second chamber; each of the chambers having gas inlet and outlet means and adapted to receive and expel pressurized gas; (ii) moveable member means associated with the chambers; (b). means for providing pressurized gas to the chambers; (c) means for releasing pressurized gas from the chambers; and (d) means for providing timing and synchronized control of pressurized gas into and out of the chambers to effect movement of the moveable member means to provide the electric output. The apparatus and process allows for the efficient utilization of low grade heat, for example, from geothermal, waste cooling fluids and other types of waste heat sources.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to the production of electric current by electromagnetic generation means, particularly a linear generator, from a pressurized gas provided particularly from a low grade heat source. 
       BACKGROUND OF THE INVENTION 
       [0002]    Utilization of so-called low grade heat, for example, from cooling processes carried out in heat transfer equipment is minimal. Traditional so-called waste heat recovery systems are generally based on the Rankine cycle involving turbine-generator to provide power. 
         [0003]    Similar systems have been used to cooperate power from geothermal water sources. 
         [0004]    However, there is a need for improved apparatus and processes of generating electricity from such relatively low heat sources. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    The present invention generally comprises a generator configured for generating electrical energy utilizing low grade heat or waste heat. 
         [0006]    In one aspect, the invention provides an apparatus for generating an electric current comprising 
         [0007]    (a) electromagnetic means having
       (i) a plurality of gas receiving chambers comprising at least a first chamber and a second chamber; each of said chambers having gas inlet and outlet means and adapted to receive and expel pressurized gas   (ii) moveable member means associated with said chambers;       
 
         [0010]    (b) means for providing pressurized gas to said chambers; 
         [0011]    (c) means for releasing pressurized gas from said chambers; and 
         [0012]    (d) means for providing timing and synchronized control of pressurized gas into and out of said chambers to effect movement of said moveable member means to provide said electric current. 
         [0013]    In one aspect, the invention provides an apparatus for electrical power generation comprising
       (A) linear generator means comprising
           a housing;   a reciprocatable piston having a first end face and a second end face within said housing; said housing having   
               
 
         [0017]    (i) a first portion, which with said piston first end face defines a first chamber; and 
         [0018]    (ii) a second portion, which with said piston second end face defines a second chamber; 
         [0019]    magnet means and electromagnetic coil means cooperable with said piston and said magnet means whereby operable reciprocatable movement of said piston effects generation of electric current in said electromagnetic coil means; wherein said first chamber has first gas first inlet and outlet means; and said second chamber has second gas second inlet and outlet means;
       (B) first valve means to operably control passage of feed said first gas through said first inlet into said first chamber and spent first gas through said first outlet out of said chamber;   (C) second valve means to operably control passage of feed said second gas through said second inlet into said second chamber and spent second gas through said second outlet out of said chamber; wherein said first valve means is adapted to receive said feed first gas and said second valve means is adapted to receive said feed second gas.       
 
         [0022]    The apparatus as hereinabove defined according to embodiments has said first gas first inlet and outlet means comprising first inlet means and distinct first outlet means, and said second gas second inlet and outlet means comprising second inlet means and distinct second outlet means. 
         [0023]    In a further embodiment, the invention provides an apparatus as hereinabove defined wherein said first valve means comprises feed said first gas valve means and distinct spent first gas valve means; and said second valve means comprises feed said second gas valve means and distinct spent second gas valve means. 
         [0024]    The magnet means comprises piston magnet means wherein said piston magnet means comprises magnet means affixed to said piston. 
         [0025]    In a further embodiment the piston. is formed in whole or in part of a magnetic material. 
         [0026]    In a further embodiment the housing is formed in whole or in part of a magnetic material. 
         [0027]    In a further embodiment the housing is affixed or adjacent magnet means. 
         [0028]    In a further embodiment the electromagnetic coil means is adjacent said housing. 
         [0029]    In a further embodiment the electromagnetic coil means is adjacent said piston. 
         [0030]    The piston comprises said electromagnetic coil means. 
         [0031]    According to an embodiment, the feed first gas and said feed second gas are common 
         [0032]    According to an embodiment, the invention provides an apparatus as hereinabove defined further comprising heat exchanger means comprising; means for feeding a heat-source fluid to said heat exchanger means; means for feeding a heat-receiving fluid to said heat exchange to operably effect heat exchange with said heat-source fluid to produce a pressurized heated gas comprising a gas selected from the group consisting of said feed first gas, said feed second gas and combinations, thereof. 
         [0033]    While gas at high pressures is of value in the practice of the invention, relatively low pressures of 80 psi to 150 psi are also valuable. 
         [0034]    According to an embodiment, the invention provides an apparatus comprising synchronization control means wherein said first valve means and second valve means are synchronized to operably effect simultaneous first valve means opening with said second valve means closing, alternately, with first valve means closing with second valve means opening to effect continuous reciprocating piston movement cycles. 
         [0035]    According to an embodiment, the synchronization control means comprises CPU control means operating under stored program or software control. 
         [0036]    According to an embodiment, the apparatus comprises a plurality of linear generator means in parallel or series. 
         [0037]    In an alternative embodiment, the invention provides an apparatus for electrical power generation comprising a housing having a cylindrical wall and a central longitudinal axis; a plurality of radial vanes within said housing operably rotatable around said central axis; said vanes with said wall define a plurality of chambers wherein each chamber has a wall portion; gas inlet and outlet means within each of said wall portions; valve means cooperable with each of said gas inlet and outlet means to operably control passage of a feed gas through each of said inlets into each of said chambers and spent gas through each of said gas outlets out of each of said chambers; magnet means and electromagnetic coil means cooperable with said vanes whereby operable rotary movement of said vanes effects generation of electric current in said electromagnetic coil means. 
         [0038]    In an embodiment the invention provides an apparatus as hereinabove defined wherein each of said gas inlet and outlet means comprise inlet means and distinct outlet means. 
         [0039]    In a further embodiment the invention provides an apparatus as hereinabove defined wherein said valve means comprises feed gas valve means and distinct spent gas valve means. 
         [0040]    In yet a further aspect, the invention provides a method for producing an electric current by electromagnetic means comprising a plurality of chambers having gas inlet and outlet means; said method comprising
       (a) (i) feeding a first pressurized gas to a first chamber of said electromagnetic means to provide a first pressure within said first chamber;
           (ii) synchronized releasing of a second pressurized gas from a second chamber to effect movement of said moveable member means to provide an electric current;   
           (b) (i) feeding a third pressurized gas to said second chamber of said electromagnetic means to provide said second pressure within said second chamber;
           (ii) synchronized releasing of said pressurized gas from said first chamber to effect movement of said moveable member means to provide an electric current; and   
           (c) subsequently repeating steps (a) and (b) to provide continuous electric current.       
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0046]    In order that the invention may be better understood, embodiments will now be described, by way of example only, with reference to the accompanying drawings wherein 
           [0047]      FIGS. 1 and 2  represents schematic diagrams of apparatus and processes according to embodiments of the present invention; 
           [0048]      FIG. 3  represents a schematic diagrammatic longitudinal cross-section of a linear generator according to an embodiment of the present invention; 
           [0049]      FIG. 4  represents schematic diagram of a plurality of linear generators arranged in parallel according to an embodiment of the present invention. 
       
    
    
       [0050]    In the drawings, like numerals or references indicate like elements or parts. 
       DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0051]    Reference is first made to  FIG. 1 , which shows an apparatus according to the invention and indicated generally by reference  10 . According to an embodiment, the apparatus  10  comprises three modules or interconnected circuits denoted by dotted lines “A”, “B” and “C”. 
         [0052]    Circuit A comprises a self-contained vapour-liquid heat transfer and force generating circuit, Circuit B comprises an electromagnetic linear generator for producing electric current, and Circuit C comprises a magnet cooling system. 
         [0053]    According to an embodiment, Circuit A comprises a vaporizer  12 , expander  14  condenser  16 , liquid reservoir  18  linked through gaseous and liquid conduits and valves as hereinafter described. 
         [0054]    Reservoir  18  acts as a holding tank for a fluid or condensate  20 , such as a suitable Freon gas, and is connected by conduit  22  through high pressure pump  24  and flow meter  26  to a vaporizer  12 , for example, configured as a shell and tube heat exchanger vaporizer. Vaporizer  12  has a heat fluid inlet conduit  28 , a fluid outlet conduit  30 , and gaseous outlet  32 . According to an embodiment, the heat fluid inlet conduit  28  is coupled to a low grade or waste heat source and the low grade heated fluid is utilized by the vaporizer  12  to convert the fluid or condensate  20  into a gas or vapor, which is outputted on the gaseous outlet  32  and used to generate forces utilized by the linear generator  34  as described in more detail below. 
         [0055]    According to an embodiment, the pressure pump  24  comprises a high pressure pump and is configured with a pump bypass valve  25 . According to one aspect, the pump bypass valve  25  is configured to adjust the flow of condensate from the reservoir  18 , the condensate supply pressure, or both, to the vaporizer  12 . According to another aspect, the pressure pump  24  is configured to be responsive to a control signal from a processor or CPU  71  (operating under stored program control) for adjusting/varying the operation of the pump  24 , for example, the RPM of the pump  24 , and the flow of the condensate is adjusted using the pump bypass valve  25 , for example, the pump bypass valve  25  is configured with a manually adjustable needle valve. 
         [0056]    With reference to  FIG. 1 , Circuit “B” comprises a linear generator indicated generally by reference  34 . According to an embodiment, the linear generator  34  includes a pair of associated gaseous inlet and outlet conduits  36 ,  38  and  36 ′ and  38 ′. 
         [0057]    Linear generator  34  comprises a piston  40  having a first end face  42  and a second end face  44  within a housing  46 . According to embodiment, the piston  40  is configured for reciprocating linear movement within the generator  34 . Housing  46  and end face  42  define a first chamber  48 , and housing  46  and end face  44  define a second chamber indicated generally by reference  48 ′. Housing  46  has an inlet  50  and outlet  52  for first chamber  48 , and an inlet  50 ′ and outlet  52 ′ for second chamber  48 ′. 
         [0058]    The linear generator  34  is shown in greater detail in  FIG. 3  and described below. 
         [0059]    As part of Circuit A, conduit  32  is in communication with first chamber  48  through inlet  50  under the control of valve  54 , and with second chamber  48 ′ through inlet  50 ′ under the control of valve  54 ′. 
         [0060]    Conduit  56  is in communication with first chamber  48  through outlet  52  and expands  14  under the control of valve  58 . Conduit  56 ′ is in communication with second chamber  48 ′ through outlet  52 ′ and expander  14  under the control of valve  58 ′. 
         [0061]    According to an embodiment, the control valves  54 ,  58 ,  54 ′,  58  comprise controllable values that are configured to be responsive to one or more control signals for actuating the valve. According to an embodiment, a controller  71 , e.g. a central processing unit or processor, is provided that is operatively coupled to the control valves and other controllable components and configured to operate under stored program control (e.g. execute instructions or executable code in the form of firmware or software stored in memory) to provide the functionality as described. 
         [0062]    Expander  14  is connected to condenser  16  by conduit  60  and magnet cooling Circuit “C” by feed and return conduits  62  and  64 , respectively. 
         [0063]    Condenser  16  has heat exchanger cooling fluid input conduit  66 , an output conduit  68 , and liquid transfer conduit  70  to reservoir  20 . 
         [0064]    Circuit “C” comprises conduit lines  62  and  64  and is configured to provide cooling of the permanent magnets  72  of linear generator  34  shown in  FIG. 3 . According to an embodiment, the cooling circuit C is configured to circulate coolant around the magnets in the linear generator  34  and may include a pump and a bypass valve  63  for flow control. 
         [0065]    In operation, and according to an exemplary embodiment, vaporizer  12  receives low grade heat transfer fluid at a temperature of about 90° C. from, for example, a chemical plant process, waste heat source, and/or power utilities through conduit  28  for heat exchange with liquid  20  to generate pressurized Freon gas Freon  20 ′ at a typical P 1  pressure of 65 psi and 85° C. in this embodiment. 
         [0066]    With valves  54  and  58 ′ open and valves  54 ′ and  58  closed, gas  20 ′ enters first chamber  48  through inlet  50  to raise the pressure in and expansion of first chamber  48  to P 1  to produce linear movement of piston  40  and expulsion of gas  20 ′ out of chamber  48 ′ through conduit  52 ′ and valve  58 ′ to expander  14  and reduction in pressure of P 1  of about 25 psi. According to one aspect, the valves  54 ,  54 ′ and  58 , 58 ′ are configured as flow switches to allow pressure forces from the vaporizer  12  to act on the piston  40  (i.e. move the piston  40 ) and allow vapour exhaust from the chambers  48 ,  48 ′ to be removed or exhausted. The vapour exhaust is captured by the expander  14  and directed to the condenser  16  where it is condensed into liquid form and drained to the holding tank  18 . According to an embodiment, the holding tank  18  is configured with a window or other mechanism to allow determining the level of the condensate. 
         [0067]    Linear movement of magnet(s)  72  on loaded piston  40  with respect to permanent magnets  73  affects production of electric current in a coil  74 , for example, as depicted in  FIG. 3 . 
         [0068]    Synchronized closing of valves  54  and  58 ′ and opening of valves  58  and  54 ′ causes expansion of chamber  48 ′ with pressure increase to P 1  and return movement of piston  40  and generation of further electric current. Such reciprocating movement of piston  40  from the timed or synchronized opening and closing of the double paired valves, as described above, results in the controlled production of an electrical output, e.g. pulses. 
         [0069]    According to an embodiment, the valve synchronization and timing or sequenced operation is controlled by CPU  71  operating under stored program control (e.g. executing instructions in firmware or software stored in memory. According to an embodiment, the CPU  71  is configured to monitor and/or control the following parameters or variables, temperature, pressure, pump speed (e.g. RPM), piston frequency, voltage and current. 
         [0070]    Reference is made again to  FIG. 3 , which shows linear generator  34  according to an embodiment of the invention. As shown, the linear generator  34  comprises housing  46  enclosing piston  40  having end face  42  and  44 , and further includes gas inlets and outlets  50 ,  50 ′ and  52 ,  52 ′, respectively, and is connected through coil leads  75  to an electric current receiver (for example, a storage device such as a capacitor with a diode gate) embraces housing  46 . Piston  40  has a plurality of affixed permanent magnets  76 . 
         [0071]    According to an embodiment, two disc shaped permanent magnets  80 ,  81  of opposite polarity are positioned at the first end face  42  of the piston  40  and at the end face of the housing  26  cylinder so as to generate a repulsive force working on the first end face  42  of the piston  40  to avoid that the piston  40  touches end face of the housing cylinder  26 . Similarly, two disc shaped permanent magnets  82 ,  83  of opposite polarity are positioned at the second end face  44  of the piston  40  and at the end face of the housing cylinder  26  so as to generate a repulsive force working on the second end face  44  of the piston  40  so that the piston avoids touching or contacting end face of the housing cylinder  26 , i.e. when the piston  40  reaches the end of its stroke, the magnet  80  or  82  is repelled by the respective magnet  81  or  83  and force is generated to push back the piston  40 . According to an embodiment the magnets  80 , 81  and  82 , 83  comprise rare earth type magnets. The pressure difference between the vaporizer  12  and the condenser  16  results in a force which acts to move the piston  40  in the linear generator  10 . It will be appreciated that the frequency of operation for the piston  40  depends on the mass and/or geometry of the piston  40 , the resulting force generated, and/or the rebounding forces generated by the repulsive forces of the magnets  80 , 81  and  82 , 83 . 
         [0072]      FIG. 4  shows generally in part a plurality of linear generators arranged in parallel, under the control of valves  54 ,  54 ′ and  58 ,  58 ′. 
         [0073]    Reference is lastly made to  FIG. 2 , which shows a generator according to another embodiment and indicated generally by reference  100 . As shown, the generator  100  comprises a housing  102  having a cylindrical wall  104  and a central longitudinal axis X-X′. 
         [0074]    Within housing  102  is arranged a plurality of vanes  106  affixed to central longitudinal rotatable axle  108 . Vanes  106  with portions of wall  104  define a plurality of chambers  110 . 
         [0075]    Each of wall portions has an inlet  112  and outlet  114  to receive and release pressurized gas under the control of valves  116  and  118 , respectively. 
         [0076]    Pressurized gas P 1  for example, through conduits  32  produced by vaporizer  12  as hereinabove described with reference to  FIG. 1  alternately enter or leaves chambers  110  in a synchronized manner under the control of valves  112  and  114  and CPU  71 . 
         [0077]    Conduit coil  76  of electromagnetic system is affected around housing and generates electric current by rotation of magnets  78  affixed to vanes  106 . 
         [0078]    Although this disclosure has described and illustrated certain embodiments of the invention, it is to be understood that the invention is not restricted to those particular embodiments. Rather, the invention includes all embodiments which are functional or mechanical equivalence of the specific embodiments and features that have been described and illustrated.