This invention relates to power generation. More specifically, this invention relates to oscillation-driven thermoelectric power generation.
Thermoelectric generators rely on a thermal gradient formed between different nodes of a circuit to produce electrical energy. In some instances, the nodes may comprise two or more dissimilar materials. In other instances, the nodes can be part of a single material.
The following disclosure relates to improvements in thermoelectric power generation. The embodiments disclosed herein provide methods and apparatus for converting thermal energy into electrical energy.
In one representative embodiment, an apparatus can comprise a circuit and an electrical element coupled to the circuit. The circuit can include a pulse generator to generate an electrical pulse having a first power and a load. The electrical element can be configured to receive heat that is converted into electrical energy by the circuit to apply a second power, greater than the first power, to the load.
In any of the disclosed embodiments, at least a portion of the electrical element can be coupled to a heat sink. In any of the disclosed embodiments, the heat can be applied to the heat sink.
In any of the disclosed embodiments, the heat can be applied to the electrical element such that there is a thermal gradient across a length of at least a portion of the electrical element. In any of the disclosed embodiments, the electrical element can comprise a wire having a heavier gauge (i.e., a wider diameter) than conductors within the circuit that couple the electrical element to other circuit components. In any of the disclosed embodiments, a portion of the electrical pulse generated by the pulse generator can have a change in voltage with respect to time of at least 100 volts per microsecond.
In any of the disclosed embodiments, the circuit can further comprise an oscillator connected in series with the electrical element. In any of the disclosed embodiments, the circuit can further comprise an oscillator connected in parallel with the electrical element.
In any of the disclosed embodiments, the circuit can further comprise a primary oscillator and a secondary oscillator connected in series with the electrical element. In any of the disclosed embodiments, at least one of the primary or secondary oscillator can be an LC circuit.
In any of the disclosed embodiments, a rising voltage of the electrical pulse can cause the primary oscillator to oscillate at a first frequency and the secondary oscillator to oscillate at a second frequency greater than the first frequency. In any of the disclosed embodiments, the circuit can further comprise an inductive element and/or a capacitor tap connected in series with the secondary oscillator.
In another representative embodiment, a method can comprise generating an electrical pulse as an input to a circuit comprising a first portion with a load and a second portion with an electrical element connected to the load, absorbing heat within the electrical element, converting the absorbed heat into electrical energy to increase a power of the electrical pulse, and applying the electrical pulse with increased power to the load.
In any of the disclosed embodiments, at least a portion of the electrical element can be coupled to a heat sink. In any of the disclosed embodiments, the method can further comprise applying the heat to the heat sink.
In any of the disclosed embodiments, the method can further comprise applying the heat to the electrical element such that there is a thermal gradient across a length of at least a portion of the electrical element. In any of the disclosed embodiments, a portion of the electrical pulse can have a change in voltage with respect to time of at least 100 volts per microsecond. In any of the disclosed embodiments, the first portion of the circuit can further comprise an oscillator positioned in series with the electrical element. The oscillator can cause the circuit to convert the absorbed heat into useful electrical energy.
In any of the disclosed embodiments, the first portion of the circuit can further comprise a primary oscillator and a secondary oscillator connected in series with the electrical element. In any of the disclosed embodiments, a rising voltage of the electrical pulse can cause the primary oscillator to oscillate at a first frequency and the second oscillator to oscillate at a second frequency greater than the first frequency.
In any of the disclosed embodiments, generating the electrical pulse can comprise during a first time interval, opening a second switch connected to ground and then closing a first switch connected to a power supply, and during a second time interval, opening the first switch and then closing the second switch.
In another representative embodiment, an apparatus can comprise a circuit and an electrical element coupled to the circuit. The circuit can include a pulse generator to generate an electrical pulse and a primary oscillator coupled to the pulse generator. The circuit can be configured to supply the electrical pulse to a load with a greater power than the power supplied by the pulse generator. In any of the disclosed embodiments, the circuit can further comprise a secondary oscillator coupled to the primary oscillator.
The foregoing and other objects, features, and advantages of the invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.
This disclosure concerns embodiments of thermoelectric transducers that can be used for thermoelectric power generation. Traditional thermoelectric devices are an inefficient means of converting thermal energy into electrical energy. One reason for this inefficiency is the lack of control in transporting thermodynamic from a heat source to a heat sink due to diffusion (e.g., Newton cooling). However, an oscillating source of heat applied to a thermoelectric conductor can result in a considerable increase in the thermoelectric efficiency of the conductor.
Various improvements to thermoelectric power generation are disclosed herein. The disclosed embodiments can be used for various applications requiring power such as transportation (e.g., marine, ground, flight), remote location systems including autonomous powering of Internet of Things devices, power for sensing, tracking, communication, analytics, processing and interoperability of devices, powering of wearables, smart textiles with embedded electronics, among other applications. Additionally, embodiments disclosed herein can be used for power intensive applications and processes such as water purification, vertical and traditional agriculture, chemical and petrochemical processing, data center power and cooling, facility and environmental controls (e.g., industrial, commercial, residential). The embodiments disclosed herein can also complement existing power infrastructures including as a complement to solar farm infrastructure, wind and other intermittent renewable energy systems, dual purpose power sources, data centers, thermal management or cooling mechanisms (e.g., heat sinks), charging mechanisms for energy storage devices, lighting power sources, and as an integral power source for consumer electronics including telecommunications devices. Additionally, embodiments described herein can be used with home and industrial devices such as refrigeration and other cooling applications (e.g., air conditioning) and in combination with structural or other surfaces (e.g., roofing). More generally, anything that can be powered by electrical means can be supported by the embodiments disclosed herein regardless of the availability of an externally connected power source.
When the pulse generator 102 outputs an electrical pulse having a high dV/dt, the electrical element 104 converts thermal energy to electrical energy, as described herein. The electrical element 104 should have a conductive path with sufficient surface area to absorb heat, thereby allowing the electrical element to act as a heat sink. This can be achieved by the electrical element 104 having a heavier gauge, a greater length, or a non-cylindrical shape with greater surface area. In some examples, the electrical element 104 can be a copper wire having a gauge (e.g., 10 AWG) that is heavier than the wires or electrical conductor connecting the electrical element to the pulse generator 102 and the load 106. In other examples, the electrical element 104 can comprise any other conductive material. In one example, the electrical element 104 is a heavier gauge wire with respect to other signal conductors in the circuit and has a length of at least three feet. The electrical element 104 can be a simple wire, a coil, or any conductive element that can absorb heat. When the electrical pulse output by the pulse generator 102 with a high dV/dt ratio is applied to one side of the electrical element 104, the electrical element gets colder and a voltage appears on the other side the electrical element with a higher power level than what was produced by the pulse generator 102. As such, the sharp pulse output by the pulse generator 102 causes the electrical element 104 to convert thermal energy into electrical energy. The higher the dV/dt ratio of the pulse output by the pulse generator 102, the greater the amount of thermal energy that is converted to electrical energy. This phenomena can be referred to as Kinetic Power Transient (KPT).
In the illustrated example of
If the pulse generator 102 continually outputs electrical pulses at periodic intervals, the electrical element 104 converts thermal energy to electrical energy with each pulse and increases the power of each pulse applied to the load 106. However, each time the electrical element 104 receives a pulse, it cools in order to convert thermal energy to electrical energy. As this happens, the temperature gradient between the electrical element 104 and the surrounding environment causes heat to be transferred from the environment to the electrical element, which causes the temperature of the electrical element to rise until it equalizes with the temperature of the environment. When the next electrical pulse is emitted by the pulse generator 102, the electrical element 104 again cools as it converts thermal energy to electrical energy. Thus, the amount of thermal energy that the electrical element 104 can convert into electrical energy is limited by the surrounding environment. In some examples, this cooling effect can allow the electrical element to be used as a cooling or refrigeration element.
In the example of
In operation, the pulse generator 102 of
The electrical element 104 can be positioned in series with an inductor 608 and a capacitor 610, which together can form an oscillator similar to the oscillator 302 of
An additional transformer 612 can receive the signal output by the electrical element 104 and can be connected to a full-bridge rectifier 614, which can convert the AC signal from the transformer 612 into a DC signal. In some examples, the full-bridge rectifier 614 can be replaced with a half-bridge rectifier. The outputs of the rectifier 614 can be connected to a load capacitor 616 and a load resistor 618. In some examples, the circuit 600 can include the capacitor 616 and not the load 618. In other examples, the circuit 600 can include the load 618 and not the capacitor 616. The capacitor 616 can store the electrical energy output by the rectifier 614. The load 618 can consume the electrical energy output by the rectifier 614.
The pulse generator 102 can be connected to a transformer 706 that can amplify the electrical pulses output by the pulse generator. The circuit 700 can also include an inductor 708 and a capacitor 710 that can form a primary oscillator similar to the primary oscillator 402 of
A capacitor tap 714 can withdraw energy output by the electrical element 104. The capacitor tap 714 can be connected to diodes 716 and 718, which can form a half-bridge rectifier, and which can convert AC power into DC power. The circuit output is shown as a resistor 720 and capacitor 722, which can consume and/or store electrical power. In some examples, the circuit 700 can include the resistor 720 without the capacitor 722. In other examples, the circuit 700 can include the capacitor 722 without the resistor 720.
The circuit 800 can include an op-amp 802, which can receive an input voltage Vp and output a square wave or other signal having a high dV/dt ratio, similar to the pulse generator 102 of
These oscillations and the high dV/dt ratio of the signal output by the op-amp 802 can cause the electrical element 104 to convert thermal energy into electrical energy and increase the power of the received electrical signal. Resistors 816 and 818, which can represent a first and second load, can consume the electrical power output by the electrical element 104. In some examples, the resistors 816, 818 can have inductance, which may contribute to the oscillations.
The circuit 900 can include a first switch 904 and a second switch 906 that can be controlled by a microprocessor 908. The microprocessor 908 can independently open and close the switches 904, 906. The first switch 904 can be connected to a power supply 910 and the second switch 906 can be connected to ground. The switches 904, 906 can be in parallel and can be connected to a capacitor 912. The microprocessor can alternatingly open and close the switches 904, 906 so as to output a square wave. During a first time interval, the microprocessor 908 can close switch 904 and open switch 906. This causes the voltage from the power supply 910 to be applied to the capacitor 912, thereby causing a positive voltage to accumulate on one plate of the capacitor. During a second time interval, the microprocessor 908 can open the switch 904 and close the switch 906. This grounds the capacitor, thereby causing a negative voltage to appear on the capacitor plate. This process can then be continued, with the microprocessor 908 repeatedly opening one of the switches 904, 906 and closing the other one, thereby producing an alternating series of positive and negative voltages to appear at point 914 of the circuit 900.
The circuit 900 can further comprise a transformer 916 to amplify the voltage output created by the voltage source 910 and the switches 904, 906. The transformer 906 is connected to a primary oscillator 918 comprising an inductor 920 and a capacitor 922 and a secondary oscillator 924 comprising the capacitor 922 and an inductor 926. The primary oscillator 918 can be similar to the primary oscillator 402 of
At process block 1110, the pulse generator 102 generates an electrical pulse with a high dV/dt ratio. For example, in
In view of the many possible embodiments to which the principles of the disclosed invention may be applied, it should be recognized that the illustrated embodiments are only preferred examples of the invention and should not be taken as limiting the scope of the invention. Rather, the scope of the invention is defined by the following claims. We therefore claim as our invention all that comes within the scope of these claims.
This application is a continuation of U.S. application Ser. No. 16/137,338, filed on Sep. 20, 2018, which claims priority from U.S. Provisional Application No. 62/568,244, filed Oct. 4, 2017, which applications are incorporated herein by reference in their entirety.
Number | Date | Country | |
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62568244 | Oct 2017 | US |
Number | Date | Country | |
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Parent | 16137338 | Sep 2018 | US |
Child | 17583949 | US |