Abstract:
A device and method for generating electricity. The device includes a heat source, a cold source, and a thermoelectric generating plate, having a first side and an opposed side. When heat is introduced to the heat source, heat flows across the thermoelectric generating plate and electricity is generated. In the present arrangement, because the hot and cold sources are in thermal communication with opposed sides of the thermoelectric generating plate, the thermal gradient or rate of heat flow across the thermoelectric generating plate is maximized. Thus, because the rate of heat flow is increased, the rate at which electricity is generated is also increased, and the size of the device is maintained, or minimized.

Description:
BACKGROUND 
       [0001]    The present disclosure relates to a device and system for generating electricity. In particular, the present disclosure relates to a device and method for generating electricity through the use of thermoelectric generators. 
         [0002]    At present, there are many ways of generating power for use in powering electronic devices. Most prevalent is the use of direct current or alternating current by means of a battery supply. Battery supplied power is limited and requires recharging. Recharging requires access to a power supply. Moreover, battery supplied power can be heavy as batteries become increasingly heavier as the power requirement increases. For example a battery having a higher power output will typically be heavier than one having a lower power output. Some batteries are lighter than others depending upon the materials used, but increase relatively in weight and size as the power requirements increase. 
         [0003]    In some situations, there is a need for a continuous power supply for use in powering personal electronic devices, such as a cell phone or personal digital assistant, or the like. In particular, there is a need for a power supply for use in powering electronic devices used remotely, primarily by military and rescue personnel. Presently, portable power systems do not provide sufficient power for an extended period of time. Thus, additional power supplies must be carried as back-up power supplies, or a recharging system requiring access to electricity. 
         [0004]    Thus, there is a need for an improved, light weight, compact, sustainable power supply. 
       SUMMARY OF THE INVENTION 
       [0005]    In accordance with an embodiment of the present disclosure a device for generating electricity may include a heat source, a cold source, and a thermoelectric generating plate. The thermoelectric generating plate includes a hot side and a cold side. The hot side of the thermoelectric generating plate is in thermal communication with the heat source and the cold side of the thermoelectric generating plate is in thermal communication with the cold source. Heat flux across the thermoelectric generating plate causes electrical power to be generated. 
         [0006]    In accordance with another embodiment of the present disclosure, a device for generating electrical power may include a heat source, a cold source, and a thermoelectric generator stack. The thermoelectric generator stack may include a plurality of thermoelectric generators, each generator including a cold side and a hot side. The thermoelectric generator stack may also include a first plurality of thermal elements. Each of the first plurality of thermal elements may be thermally coupled to the heat source and to the hot side of an associated one of the plurality of thermoelectric generators to transfer thermal energy from the heat source to the thermoelectric generator. The thermoelectric generator may further include a second plurality of thermal elements. Each of the second plurality of thermal elements may be thermally coupled to the cold source and to the cold side of the associated one of the plurality of thermoelectric generators to transfer thermal energy from the thermoelectric generator to the cold source. Heat generated by the heat source causes a thermal gradient across each of the thermoelectric generators to generate electrical energy. 
         [0007]    In accordance with another embodiment of the present disclosure, an electrically powered device may include electrical circuitry to perform a predetermined function. The electrically powered device may also include a device for generating electrical power to operate the electrical circuitry. The device for generating electrical power may include a thermoelectric generator stack. The thermoelectric generator stack may include a plurality of thermoelectric generators or plates. Each generator or plate may include a cold side and a hot side. The thermoelectric generator stack may also include a first plurality of thermal elements. Each of the first plurality of thermal elements may be thermally coupled to a heat source and to the hot side of an associated one of the plurality of thermoelectric generators to transfer thermal energy from the heat source to the thermoelectric generator. Each of the second plurality of thermal elements may be thermally coupled to a cold source and to the cold side of the associated one of the plurality of thermoelectric generators to transfer thermal energy from the thermoelectric generator to the cold source, wherein heat generated by the heat source causes a thermal gradient across each of the thermoelectric generators to generate electrical energy. 
         [0008]    In accordance with a further embodiment of the present disclosure, a method for generating electrical power may include creating a thermal gradient across each of a plurality of thermoelectric generators formed in a generator stack. The generator stack may be formed by stacking a first plurality of thermal elements each thermally coupled to a heat source and to a hot side of an associated one of the plurality of thermoelectric generators to transfer thermal energy from the heat source to the thermoelectric generator. The generator stack may also be formed by stacking a second plurality of thermal elements each thermally coupled to a cold source and to a cold side of the associated one of the plurality of thermoelectric generators to transfer thermal energy from the thermoelectric generator to the cold source, wherein the thermal gradient across each of the thermoelectric generators generates electrical energy. The method may also include supplying the electrical power to a connector to power an electrical device. 
         [0009]    Features and advantages of the present disclosure will become more apparent in light of the following detailed description of some embodiments thereof, as illustrated in the accompanying Figures. As will be realized, the disclosure is capable of modifications in various respects, all without departing from the spirit and scope of the disclosure. Accordingly, the drawings and the description are to be regarded as illustrative, and not as restrictive in nature. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0010]      FIG. 1  is a perspective view of an example of a device for generating electrical power in accordance with an embodiment of the present disclosure. 
           [0011]      FIG. 2  is a cross-sectional view of a portion of the device of  FIG. 1  illustrating a thermoelectric stack in accordance with an embodiment of the present disclosure. 
           [0012]      FIG. 3  is a block diagram of an example of an electrically powered device powered by a device for generating electrical power in accordance with an embodiment of the present disclosure. 
       
    
    
     DESCRIPTION 
       [0013]    The disclosure will now be described with reference to the accompanying drawings which illustrate disclosed embodiments of the device and method for generating electrical power of the present disclosure falling within the scope of the appended claims. Other embodiments having different structures and operations do not depart from the scope of the present disclosure. 
         [0014]    Referring now in more detail to the drawings in which like numbers indicate like parts throughout the several views,  FIG. 1  is a perspective view of a device  10  for generating electrical power in accordance with an embodiment of the present disclosure. The device  10  includes a heat pipe stack  12  and a cold pipe stack  14 . The heat pipe stack  12  is in thermal communication with a heat source  13 . Examples of the heat source  13  may include a combustion chamber, magnesium burner or any heat source that is compact and light weight. The heat source may also include a solar based heat source. The cold pipe stack  14  is in thermal communication with a cold source  15 . Examples of the cold source  15  may include a cooling fan to exhaust to the atmosphere, a heat sink or other device. The cold source  15  may also just be a surface area exposed to the air or atmosphere or a vent to air. It should be noted that other devices for generating heat such as a combustion chamber may be used in lieu of the magnesium burner  13 . Also, the cooling fan  15  may be substituted with other known means to remove heat from a space. 
         [0015]    Referring also to  FIG. 2 ,  FIG. 2  is a cross-sectional view of a portion of the device  10  of  FIG. 1  illustrating a thermoelectric stack  26  in accordance with an embodiment of the present disclosure. The thermoelectric stack  26  includes a series of thermal elements, such as heat pipes  16 , cold pipes  18 , and thermoelectric generators  20  or plates in a particular order. In one embodiment, the heat pipes  16  and cold pipes  18  may be nano pipes, nano tubes or the similar thermal elements The heat  16  and cold pipes  18  are to be made of anything that is thermally conductive such as copper, aluminum nitride or the like. As shown in  FIG. 2 , the heat pipes  16  extend outwardly in a parallel fashion from the heat source  13  in at least one direction. The heat pipes  16  are thermally coupled to the heat source  13  in such a way as to ensure effective heat transfer from the heat source to and through the heat pipes  16 . Similarly as shown in  FIG. 2 , the cold pipes  18  extend from the cold source  14  in a parallel fashion and in an opposed direction to the heat pipes  16  so that the cold pipes and heat pipes overlap when the device is assembled. The cold pipes  18  are thermally coupled to the cold source  14  in such a way as to ensure effective heat loss from the cold pipes to and through the cold source so as to maintain a low temperature relative to the heat pipe  16 . 
         [0016]    Sandwiched between each heat pipe  16  and cold pipe  18  in the stack  26  is a thermoelectric generator  20 , as shown in  FIG. 2 . Each thermoelectric generator  20  has a hot side surface  22  and a cold side surface  24 . The hot side surface  22  is in thermal contact with the heat pipe  16 . The cold side surface  24  is in thermal contact with the cold pipe  18 . The thermoelectric generator  20  creates electrical power from the heat flow across a structure. One type of thermoelectric generator is a solid state thermoelectric converter made by Eneco. If the thermal gradient (difference in temperature between the heat source  12  and cold source  14 ) increases, the flow of heat across a structure increases and thus a greater amount of electrical power or energy may be generated. At a minimum, a stack  26  would include at least one heat pipe  16  and at least one cold pipe  18  with a thermoelectric generator  20  sandwiched in between. Moreover, it is preferred that the hot side surface  22  and the heat pipe  16  be made of materials having coefficients of thermal expansion that differ by no more than 10%. Similarly, it is preferred that the cold side surface  24  and the cold pipe be made of materials having coefficients of thermal expansion that differ by no more than 10%. When the coefficients of thermal expansion are similar between the hot  22  and cold side  24  surfaces and the heat  16  and cold pipes  18 , the device  10  funtions more effectively because the interaction between the surfaces (cold pipe and cold side, and heat pipe and hot side surface) expand and contract at similar rates so the heat transfer is more efficient. 
         [0017]    The stack  26  arrangement of heat pipes  16 , cold pipes  18  and thermoelectric generators  20  enables the device  10  to be arranged in a compact manner while generating greater levels of electrical power or energy than presently provided by existing systems. Moreover, the stacking arrangement of the exemplary embodiment of the present disclosure illustrated in the Figures allows for a greater heat flow across each thermoelectric generator  20  and increases the effectiveness of each generator  20  and the device  10  as a whole. Thus, the device  10  of the illustrated embodiment of the present disclosure enables a greater amount of electrical power or energy to be generated while enabling the size and weight of the device  10  to decrease. 
         [0018]    Returning to  FIG. 1 , insulating material  28  is positioned between the cold pipes  18  and the hot heat pipes  16 . The insulating material  28  inhibits the transfer of heat from the hot heat pipe  16  directly to the cold pipe  16 . By preventing heat flow between the heat pipe  16  and cold pipe  18  outside the stack  26 , the insulating material  28  further enables the device  10  to more effectively produce a greater amount of electricity. The insulating material  28  may include an alumina enhanced thermal barrier or similar insulating material. A thermal chip module layer  29  may be embedded in the alumina enhanced thermal barrier. 
         [0019]    A power conditioner and plug  38  or outlet are electrically connected to the thermoelectric generators  20  of the device  10  so as to provide the user with a way of transferring or supplying the electrical power from the device  10  to the user&#39;s electronic device. 
         [0020]    A control module  40  may also be associated with the device  10  to control the operation of the device  10 . The set of control functions to be considered may include: controlling the rate of fuel to be combusted to produce the heat source for the hot side. In particular, the control module  40  may regulate the bum rate of the magnesium or other fuel in such a way in order to maintain the proper temperatures and thermo gradients in the device  10  for effective operation. Additional control functions may include controlling the operation of fans for cooling the cold side, and controlling the level of voltage to be generated for interfacing with intended application device. 
         [0021]    The device  10  further includes a warm start battery  42  and a cold start module  44  The warm start battery stores enough energy to add and ignite fuel for a hot system restart after the system has been turned off for a period of time. The cold start module can be a hand crank generator which charges the warm start battery  42 . It allows the start of the device  10  if battery  42  is discharged. 
         [0022]    In a one embodiment, it is anticipated that the overall dimensions of the device  10  would be about 74 mm high, 125 mm wide and 43 mm thick, and would include six layers of thermoelectric generators capable of generating a total of 300 watts of power from the device  10 . It is appreciated that the dimensions would vary with changes to design, function and power generating capability of the device  10 . 
         [0023]      FIG. 3  is a block diagram of an example of an electrically powered apparatus  50  powered by a device  52  for generating electrical power in accordance with an embodiment of the present disclosure. The electrically powered apparatus  50  may be a mobile or portable electrically powered device that heretofore may have been powered by an electric storage battery or other electricity storage device. The electrically power apparatus  50  may be communications device, computing device or other electrical device. 
         [0024]    The electrically powered apparatus  50  may include circuitry  54  for performing a predetermined function. For example in the case of a communications device, the circuitry  54  may include a transmitter and a receiver. The apparatus  50  may also include a user interface  56  to permit a user to control the device. The interface  56  may include a keypad, keyboard, computer pointing device or mouse, display or any other means to permit a user to operate and control the apparatus  50 . The electrically powered apparatus  50  may also include other components, such as a data storage device, file system, processing unit or the like. 
         [0025]    The device  52  for generating electrical energy of power may be similar to the device  10  in  FIG. 1 . The device  52  may include a thermoelectric generator stack  60 . The thermoelectric generator stack  60  may be similar to the generator stack  26  in  FIGS. 1 and 2  and may operate in a substantially similar manner. The thermoelectric stack  60  may be thermally coupled to a heat source  62  and a cold source  64  to create a thermal gradient across the thermoelectric generators or plates in the thermoelectric stack  60  to generate electrical energy. 
         [0026]    Electrical energy generated by the thermoelectric stack  60  may be conditioned by a conditioning circuit  66 . The conditioning circuit  66  may be controlled by a control module  68  so that the appropriate voltage and current levels are supplied to the electrically powered apparatus  50 . The control module  68  may include a user interface or the interface may be separate from the control module  68  to permit a user to select the appropriate voltage and current and any other parameters associated with the electrical power to be supplied to the apparatus  50 . 
         [0027]    The device  52  may also include a plug, outlet or similar means for supplying the electrical power to the apparatus  50 . An electrical cable or power cord  72  may also be provided to connect the device  52  to the apparatus  50 . In another embodiment of the present disclosure, the device  52  may be integrated into the apparatus  50 . 
         [0028]    The following claims are in no way intended to limit the scope of the disclosure to the specific embodiments described. It should be understood by those skilled in the art that the foregoing modifications as well as various other changes, omissions and additions may be made without parting from the spirit and scope of the present disclosure.