Abstract:
A system and method for converting kinetic to potential energy across a thermal gradient can include an endothermic unit for absorbing heat, an exothermic unit for releasing heat, and a control unit for receiving energy from an outside source to power the endothermic and exothermic units. The system can also include a first power generation unit having a plurality of thermoelectric elements which convert heat to an electrical potential across a thermal gradient, and a feedback unit for supplying the electrical potential generated by the first power generation unit to the control unit.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. provisional Patent Application Nos. 61/216,256 filed on May 16, 2009 and U.S. provisional Patent Application No. 61/268,189 filed on Jun. 9, 2009 the entire contents of each of which are hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to feedback of electric power generation. More particularly, it relates to a system and method for converting a portion of kinetic energy into potential energy across a thermal gradient. 
         [0004]    2. Description of the Related Art 
         [0005]      FIG. 1  illustrates one embodiment of a known Thermal-electric Generator (TEG) called a thermopile that is useful for understanding the inventive concepts disclosed herein. As shown, a single thermopile  10  typically includes two dissimilar metals  11  and  12  joined together at a common junction  13 . The principle behind the thermocouple  10  is based on the Seebeck effect which states that an electrical current will flow at the junction (i.e. thermocouple) of a circuit made from two dissimilar metals at different temperatures. Common examples of this principle include electronic thermometers, and miniature thermoelectric transducers such as CP2-8-31-081 made by Melcor, USA. 
         [0006]    However, the use of thermo-electric generators as a power source has traditionally been extremely limited due to the vast inefficiency of the devices which typically range from 3-9%. In this regard, in order to produce usable electricity, conventional TEG&#39;s must be exposed to a thermal gradient that is extremely high. This requirement means that a conventional thermo-electric generator would likely require more energy (in the form of heat generation) than the output (in the form of electricity) by the TEG. As a result, most thermo-electric generators are relegated to operating as a secondary power source and are often coupled with other technologies. For instance, thermo-electric generators are typically employed in solar power arrays, where there is an abundance of heat. 
         [0007]    Accordingly, it would be beneficial to provide a highly efficient thermo-electric generator with an effective low cost thermal gradient producing device in order to convert the supplied kinetic energy into electricity across the thermal gradient. Several patents have been filed for thermoelectric energy conversion including: Aspden U.S. Pat. No. 5,065,085; Kondoh U.S. Patent Publication No. 2006-0016469; and Guevara U.S. Patent Publication No. 2003-0192582, however, none of these address the issues outlined above. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention is directed to a system for converting kinetic to potential energy across a thermal gradient. One embodiment of the present invention can include an endothermic unit for absorbing heat, an exothermic unit for releasing heat, and a control unit for receiving energy from an outside source to power the endothermic and exothermic units. The system can also include a first power generation unit having a plurality of thermoelectric elements which convert heat to an electrical potential across a thermal gradient, and a feedback unit for supplying the electrical potential generated by the first power generation unit to the control unit. 
         [0009]    Another embodiment of the present invention can include a system as described above that further includes a plurality of power generation units. 
         [0010]    Yet another embodiment of the present invention can include a method for implementing the system described above. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    Presently preferred embodiments are shown in the drawings. It should be appreciated, however, that the invention is not limited to the precise arrangements and instrumentalities shown. 
           [0012]      FIG. 1  illustrates one embodiment of a Thermal-electric Generator that is useful for understanding the embodiments disclosed herein. 
           [0013]      FIG. 2  illustrates one embodiment of a thermo-electric system in accordance with the present invention. 
           [0014]      FIG. 3  illustrates a thermo-electric system in accordance with another embodiment present invention. 
           [0015]      FIG. 4  illustrates a thermo-electric system in accordance with an alternate embodiment present invention. 
           [0016]      FIG. 5  illustrates a thermo-electric system in accordance with an alternate embodiment present invention. 
           [0017]      FIG. 6  illustrates a thermo-electric system in accordance with an alternate embodiment present invention. 
           [0018]      FIG. 7  illustrates a thermo-electric system in accordance with an alternate embodiment present invention. 
           [0019]      FIG. 8  is a flow chart illustrating a method for converting a portion of kinetic energy to potential energy across a thermal gradient producing system, in accordance with another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the description in conjunction with the drawings. As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the inventive arrangements in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of the invention. 
         [0021]    As used throughout this document, a thermopile can include an array of thermocouples in a discrete package, aligned parallel to each other on a plane that is perpendicular to the direction of the thermal gradient. Moreover, a Thermo-electric Generator (TEG) can include a device for generating electric potential from a thermal gradient, one embodiment of which consists of multiple thermopiles arranged serially in relation to each other along the axis of the thermal gradient. Moreover, although described below as utilizing a heat pump, the inventive concepts disclosed herein are not so limited. To this end, virtually any sustainable thermal gradient producing device satisfying the criteria below can be utilized. 
         [0022]    One example of a sustainable thermal gradient producing device is a conventional heat pump. In this sense, a heat pump absorbs heat energy from the endothermic side via an evaporator and releases the heat energy to the exothermic side via a condenser. Both the endothermic and exothermic reactions are multiples of the input energy needed to trigger the process. To this end, the coefficient of performance also known as the Primary Energy Ratio (PER) of a thermal gradient producing device (i.e., heat pump) can be defined by the equation: 
         [0000]      PER=( Q+W )/ W    
         [0000]    where Q is the kinetic energy absorbed in the endothermic process, and W is the energy provided to the heat pump to do the work. In this case, work (W) is defined as both the energy used by the heat pump to generate the thermal difference and the energy lost in a delivery mechanism such as a compressor. 
         [0023]    For purposes of describing this invention we will define Primary Energy Ratio (PER) as the Energy Pumping ratio of the Endothermic, and Exothermic process which is used for the generation of the Thermal Gradient. Whereas we will define the Coefficient of Performance to be that of the overall system defined by the equation: 
         [0000]      COP=( Q+W )/( W−C ) 
         [0000]    where Q is the kinetic energy absorbed in the endothermic process, W is the energy needed for the heat pumping process to do the work, and C is the energy recollected by the TEG. 
         [0024]    As stated above, a thermo-electric generator (TEG) is a device that can convert kinetic to potential energy by transforming heat into electricity. A TEG can include a single thermopile or an array of thermopiles arranged electrically in series and thermally in parallel in order to achieve high electrical and thermal conductance. One example of a TEG is described in U.S. Patent Publication No. 2008/0283110, to Jin et al., the contents of which are incorporated herein by reference. 
         [0025]    To this end, Jin describes a TEG capable of converting a 100° Celsius thermal gradient into electric potential at efficiencies of 40-80%. Of course one of skill in the art will recognize that this is but one example of a TEG that can be used in combination with the inventive concepts disclosed herein. For instance, in one embodiment, an array of thermopiles may also be incorporated into a semiconductor material that includes low energy p-type semiconductor elements and higher energy n-type semiconductor elements, or the array may be formed using materials which are known to convert heat to an electrical current when the ends thereof are exposed to a temperature differential. 
         [0026]    In either case, for the purposes of this disclosure, any TEG having an efficiency (E) defined by the equation: E=P/(Q+W), where P is the potential energy generated by the TEG, Q is the kinetic energy provided to the TEG and W is the energy necessary to do the work can be utilized. 
         [0027]    When introducing a TEG as described above within the thermal gradient of a thermal gradient producing device, such as a heat pump, for example, it is possible to generate potential energy which can be used by external applications. To this end, this energy can be transmitted back via the transmission lines used to provide an initial energy to the system, or can be supplied directly to other devices. Alternatively, the potential energy can be fed back into the system in order to greatly improve the overall COP of the heat pump itself, with the COP approaching infinity as E approaches 1/(PER). For example, if the Primary Energy Ratio (PER) of the heat pump is 5, then a TEG having an efficiency (E) of 5% could improve the COP of the overall system from 5 to 6.7. 
         [0028]    Moreover, in another embodiment, a system that includes a TEG arranged within the thermal gradient of a heat pump satisfying the equation: E&gt;1/(PER), can potentially generate enough potential electric energy to sustain the future power requirements of the heat pump system itself. For example, a TEG having an efficiency (E) of 20% could potentially provide enough electrical energy to sustain the future operation of the same heat pump. Further, in the same example, utilizing a TEG having an efficiency (E) that is greater than 20% can potentially enable the system to produce more potential energy than the heat pump needs to operate. 
         [0029]    With respect to this invention and the embodiments outlined below, it is noted that each embodiment complies in full with the laws of thermodynamics, and in particular the Second Law of Thermodynamics. 
         [0030]    To this end, the operation of the system is based on the availability of kinetic energy in the form of excited matter, and all matter with a kinetic energy above Zero Kelvin emits Black Body radiation. Hence as the system remains running, the kinetic energy needed to operate the system will eventually decay to Entropy in the form of Black Body Radiation. However, so long as there is mater with sufficient Kinetic Energy for the Heat Pump to efficiently absorb, with a PER sufficient for the Power Generator to feed it, the system can continue to provide potential energy for general use, without other power sources. 
         [0031]      FIG. 2  illustrates one embodiment of a thermo-electric system  20  in accordance with the inventive concepts disclosed herein. Specifically,  FIG. 2  illustrates a TEG disposed between an evaporator and a condenser. 
         [0032]    System  20  can include a TEG  21 , an evaporator  22 , a condenser  23  a compressor  24  and a circulation chamber  25 . The evaporator  22  includes a cold temperature where pressurized refrigerant  28  contained in the circulation chamber  25  is allowed to expand, boil and evaporate. During this change of state from liquid to gas, energy in the form of heat is absorbed as an endothermic process. The compressor  24  acts as the refrigerant pump and recompresses the gas into a liquid. The compressor operates on electricity and the required amount fluctuates depending on the temperature difference between the evaporator and the condenser. The condenser  23  can include a hot temperature that expels the heat absorbed by the evaporator plus any additional heat produced during compression by the compressor  24 . 
         [0033]    In one preferred embodiment, the evaporator  22 , condenser  23 , compressor  24  and circulation chamber  25  can comprise an industrial grade closed-cycle phase change heat pump capable of generating temperature differentials in excess of 50°-100° Celsius with a Primary Energy Ratio (PER) exceeding 2. However, other thermal gradient producing systems are also contemplated. In another preferred embodiment, TEG  21  can include a hot portion H and a cold portion C, and having an efficiency (E) that is greater than 1/[PER (of the Heat Pump)]. In operation, the hot section H of the TEG  21  can be placed against or adjacent to the condenser  23 , while the cold section C of the TEG  21  can be placed against or adjacent to the evaporator  22 . As described above, the condenser  23  operates at an extremely high heat, whereas the evaporator  22  operates at an extremely low heat. As such, the resulting temperature differential (i.e. thermal gradient) acting upon the hot and cold sections of the TEG  21  can supply the necessary temperature gradient for the TEG to produce a voltage. The resulting power can then be fed directly to the electrical input  26  of the compressor  24  via wires  27 . Outside electricity (not shown) must also be provided to the electrical input of the system in order to create the initial thermal gradient. 
         [0034]    A thermo-electric system  20 , as described above would thus be capable of providing long lasting power which could supply continued heating, or cooling of a space, along with a small amount of extra Potential Energy for other uses. Additionally, a TEG  21  could significantly improve the overall energy efficiency, and space temperature regulation of a Heat Pump under conditions when the space being heated or cooled is close to it&#39;s preferred temperature. 
         [0035]      FIG. 3  illustrates an alternate embodiment of the thermo-electric system described above that further includes servo unit  30 . Owing to the fact that a Heat Pump&#39;s PER will significantly drop at high temperature differentials, and a TEG&#39;s Efficiency will significantly drop at low temperature differentials, servo unit  30  can be included in the system to monitor the temperature differential, and regulate the input power such that optimum differentials are maintained. As such, servo  30  can include an evaporator monitor  31  and a condenser monitor  32  for reporting the temperature of the respective components to the servo  20 . Temperature monitoring devices of this type are known and can include, for example a thermostat electrically connected to the servo or other similar means of temperature reporting device. 
         [0036]      FIG. 4  illustrates a thermo-electric system in accordance with another embodiment of the present invention. As shown, a thermo-electric system  40  can include a low thermal conductive barrier  41  interposed between the evaporator  22  and the condenser  23 . The system can further include a TEG  42  disposed between the condenser  23  and the environment to which the condenser is providing heat (See arrow D). To this end, the heat from the condenser can be used for general heating purposes, or for disposing of waste heat if the system is being used for general cooling purposes (i.e. air conditioning). As used herein, a thermal conductive barrier can include foam board or any other known insulative material. 
         [0037]    In operation, the hot section H of the TEG  42  can be placed against or adjacent to the condenser  23 , while the cold section C of the TEG  42  can be open to external environmental conditions. As such, the resulting temperature differential between the hot condenser  23  and the outside air can supply the necessary thermal gradient for the TEG to produce a voltage. The resulting power can then be fed directly to the electrical input  26  of the compressor  24  via wires  27 . 
         [0038]      FIG. 5  illustrates a thermo-electric system in accordance with another embodiment of the present invention. As shown, a thermo-electric system  50  can include a low thermal conductive barrier  41  interposed between the evaporator  22  and the condenser  23 . The system can further include a TEG  52  disposed between the evaporator  22  and the environment to which the evaporator is providing cold air (See arrow E). 
         [0039]    In operation, the cold section C of the TEG  52  can be placed against or adjacent to the evaporator  22 , while the hot section h of the TEG  52  can be open to external environmental conditions. As such, the temperature differential between the cold evaporator  22  and the outside air can supply the necessary thermal gradient for the TEG to produce a voltage. The resulting power can then be fed directly to the electrical input  26  of the compressor  24  via wires  27 . 
         [0040]    Although described above as a system having a single TEG unit, the inventive concepts also relate to the use of multiple independent TEG units working in unison. For instance,  FIG. 6  illustrates one embodiment of a thermo electric system  60  having multiple TEG units interposed between the evaporator and condenser. 
         [0041]    System  60  can include a plurality of TEG units  61   a - 61   n  interposed between the evaporator  22 , and the condenser  23 . In one embodiment, each of the TEG units can be separated by a low conductive protective barrier  62   a - 62   n . As with the above examples, the hot sections H of the plurality of TEG units  61   a - 61   n  can be placed against or adjacent to the condenser  23 , while the cold sections C of the plurality of TEG units  61   a - 61   n  can be placed against or adjacent to the evaporator  22 , thus creating the thermal gradient necessary to produce a voltage which can then be fed directly to the electrical input  26  of the compressor  24  via wires  27 . By utilizing such a configuration, independent TEG units can be added or taken away from the system in order to satisfy individual performance/power requirements. 
         [0042]      FIG. 7  illustrates an alternate embodiment of a system  70  in which multiple TEG units are utilized. As shown, a thermo-electric system  70  can include a low thermal conductive barrier  41  interposed between the evaporator  22  and the condenser  23 . The system can further include a first TEG  72   a  disposed between the condenser  23  and the environment to which the condenser is providing heat (See arrow D), and a second TEG  72   b  disposed between the evaporator  22  and the environment to which the evaporator is providing cold air (See arrow E). 
         [0043]      FIG. 8  is a flow chart illustrating a method  800  for converting a portion of kinetic energy to potential energy across a thermal gradient producing system, in accordance with another embodiment of the present invention. Method  800  can be performed by a system as described with reference to  FIGS. 2-7  above. 
         [0044]    Accordingly, method  800  can begin in step  805  where the decision to place a thermo-electric generator (such as TEG  21 , for example) within the thermal gradient of a thermal gradient producing system (such as a heat pump, for example) has been made. 
         [0045]    In step  810  a decision as to whether a thermal insulative layer is needed can be made. If the layer is needed, the method can proceed to step  815  where the thermal layer is installed into the system, otherwise the method will proceed to step  820 . 
         [0046]    In step  820 , the TEG can be positioned between the endothermic side and the exothermic side of the system. If this option is selected, the method will proceed to step  835 , otherwise the method will proceed to step  825 . 
         [0047]    In step  825 , one side of the TEG can be affixed, or adjacent to the exothermic side of the system and the other side of the TEG can face the outside environment. If this option is selected, the method will proceed to step  835 , otherwise the method will proceed to step  830 . 
         [0048]    In step  830 , one side of the TEG can be affixed, or adjacent to the endothermic side of the system and the other side of the TEG can face the outside environment, and the system can proceed to step  835 . 
         [0049]    In step  835 , the physical and electrical components of the TEG can be installed into the system. In step  840  a determination can be made as to whether the power and/or performance criteria of the system are met. If yes, the method can proceed to step  845 , otherwise the method will return to step  805  where an additional TEG can be installed. 
         [0050]    In step  845 , a determination as to whether a temperature monitoring and power regulation unit (such as monitors  30 - 31  and a servo unit  30 , for example) are desired can be made. 
         [0051]    If yes, the method will proceed to step  850  where the unit can be installed and the method will terminate. If no, the method will terminate. 
         [0000]    By incorporating the inventive concepts disclosed herein, it is possible to convert a portion of kinetic energy into potential energy across a thermal gradient. Such potential energy can be utilized to provide power to external devices or can be fed back into the thermal gradient producing system, thus greatly improving the overall COP of the system itself. 
         [0052]    The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. 
         [0053]    Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.