Thèses : « Thermoelectric, Cu2SnS3, thermoelectric generators »

1

Lohani, Ketan. « Development of Cu2SnS3 based thermoelectric materials and devices ». Doctoral thesis, Università degli studi di Trento, 2022. http://hdl.handle.net/11572/344345.

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Commercially available high-performance thermoelectric materials are often rare or toxic and therefore unsustainable. The present thesis work makes a case for eco-friendly, earth-abundant, and non-toxic p-type ceramic Cu2SnS3 (CTS, hereafter) and, in general, the use of disordered materials for thermoelectric applications. The detailed study of polymorphism, synthesis conditions, porosity, grain size, and doping provides a systematic and in-depth experimental and computational analysis of thermoelectric properties and stability of CTS. These results can be generalized for numerous thermoelectric materials and other applications. Moreover, a case for functioning thermoelectric generators using non-toxic and cost-effective materials is also presented. The thesis begins with a brief introduction to thermoelectricity, followed by a literature review and justification of the choice of the subject. The second chapter puts forward a novel approach to stabilize a disordered CTS polymorph without any chemical alteration through high-energy reactive ball milling. The third chapter deals with the stability of disordered samples under different synthesis and sintering conditions, highlighting the effect of synthesis environment, microstructure, and porosity. The fourth chapter employed a novel, facile, and cost-effective two-step synthesis method (high-energy ball milling combined with spark plasma sintering) to synthesize CTS bulk samples. The two-step synthesis method was able to constrain the CTS grain growth in the nanometric range, revealing the conductive nature of the CTS surfaces. The next chapter explores combining the two-step synthesis method with Ag substitution at the Sn lattice site to improve CTS's thermoelectric performance further. In the final stages of the thesis work, thin film thermoelectric generators were fabricated using CTS and similar chalcogenides, demonstrating power output comparable to existing thermoelectric materials used in the medium temperature range. The final chapter summarizes outlooks and future perspectives stemming from this research work.

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Alothman, Abdulmohsen Abdulrahman. « Modeling and Applications of Thermoelectric Generators ». Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/79846.

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We develop a simplified one-dimensional numerical model that simulates the performance of thermoelectric generators (TEG). The model is based on the energy and electrical potential field equations. The Seebeck coefficient, thermal conductivity, electrical resistivity and Thomson coefficient of the TEG material are used to predict the harvested power. Bismuth-telluride is used as semiconductors materials of the TEG, which is the most commonly used material by industry. Experiments on three TEG modules were performed to validate the numerical model. A comparison with predicted levels of harvested energy based on the TEG specifications is also performed. The results show differences between the experimental and numerical values on one hand and the predicted ones on the other hand. The reason for these differences are discussed. A procedure to estimate the sensitivity of the harvested power to different inputs and TEG parameters is detailed. In the second part of the dissertation, we integrate a thermoelectric generator with an organic storage device. The performance of the integrated system for different values of load resistances and temperature gradients is determined. Finally, we demonstrate that power generated from a TEG is related to the flow rate in a pipe and can, thus, be used as a flow meter. Particularly, a dimensionless relation between the TEG's peak power and Reynolds number is determined.
Ph. D.

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Glatz, Wulf. « Development of flexible micro thermoelectric generators ». Tönning Lübeck Marburg Der Andere Verl, 2008. http://d-nb.info/989530639/04.

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Twaha, Ssennoga. « Regulation of power generated from thermoelectric generators ». Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/49544/.

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In recent years, the efficiency of thermoelectric devices has improved greatly due thermoelectric material and device geometrical improvements. However, the efficiency of TEG is still low, being a subject of further research for more improvement. Hence, the main objective of the research carried out in this thesis is to analyse the performance of dc-dc converters with or without MPPT in conditioning the power generated from TEG. In light of this objective, the following case studies have been carried out. The initial study has analysed the performance of a TEG/dc-dc boost converter system. Results indicate that the converter is able to stabilise and boost the voltage and higher efficiencies are achieved at different hot side temperatures. The next study proposes the use of MPPT algorithm to harvest maximum power from TEG system. Hence, the analysis of the performance of TEG/dc-dc converter with MPPT enabled by Incremental conductance (IC) method is done. The results indicate that the IC based MPPT approach is able to track the maximum power point but with relatively lower efficiencies than the Perturb and Observe (P&O) based MPPT method. method. Another study has analysed the parameters for the performance of TEG/dc-dc converter system in different modes with a variable load. The TEG system is subjected to different hot side temperatures, including increasing step, increasing random and constant cold side temperature profiles. The study has demonstrated how the proper selection of converter components is a necessity to avoid converter losses as well interferences on the load connected to TEG/dc-dc converter system. Furthermore, another study compares the performance of extremum seeking control (ESC) and P&O MPPT algorithms applied to TEG system. The TEG model is validated with results from multiphysics (COMSOL) modelling software. To assess the effect of temperature dependency of TEG parameters, two TEG materials have been chosen; bismuth telluride (Bi2Te3) with temperature dependent Seebeck effect (S), electrical conductivity (σ) and thermal conductivity (k); and lead telluride (PbTe) with non-temperature dependent S, σ and k. Results indicate that ESC MPPT method outperforms the P&O technique in terms extracting maximum power and the simulation speed. Results also indicate that ESC outperforms the IC technique in terms of extracting maximum power and the speed of computation. ESC method is faster than the IC method. In the final study, the application of the concept and the design of a distributed dc-dc converter architecture (DCA) on TEG system is deliberated. The distributed or cascaded converter architecture involves the use of non-isolated per-TEG dc-dc converter connected to the load. Alternatively, for some specific loads, especially in automotive applications, soft-switched, isolated bi-directional dc-dc converters can be used instead of non-isolated converters because these integrated converters enable bi-directional power flow control capability. Simulations and experimental studies have been carried out to demonstrate and prove the necessity of the DCA design application on TEG systems. In addition, some of the factors affecting the performance of TEG systems are correspondingly analysed.

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Montecucco, Andrea. « Efficiently maximising power generation from thermoelectric generators ». Thesis, University of Glasgow, 2014. http://theses.gla.ac.uk/5213/.

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Thermoelectric generators (TEGs) convert the thermal energy flowing through them into DC electrical energy in a quantity dependant on the temperature difference across them and the electrical load applied, with a conversion efficiency of typically 5%. Nonetheless, they can be successfully employed to recover energy from waste heat and their use has increased rapidly in recent years, with applications ranging from microwatts to kilowatts, due to energy policy legislations and increasing energy cost determined by climate change, environmental issues and availability of energy sources. The performance of TEGs, subject to thermal and electrical effects, can vary considerably depending on the operating conditions, therefore it is necessary to measure and characterise their performance, and to understand their dynamic behaviour and interaction with the other parts of the system. Based on this knowledge it is then desired to develop an effective electronic system able to control these devices so as to maximise the power generated and increase the overall efficiency of the system. Several TEGs can be electrically connected in series and/or parallel (forming an array) to provide the required voltage and/or current. However, TEGs are usually employed in environments with time-varying temperatures, thermal powers and electrical loads. As a consequence in most TEG systems the individual thermoelectric devices can be subject to temperature mismatch due to operating conditions. Therefore it is of relevant importance to accurately simulate the evolution of thermoelectric systems during thermal and electrical transients. At the same time accurate experimental performance data are necessary to permit precise simulations. Unfortunately, there is still no standardised method to test the electrical and thermal performance of TEGs. This thesis tackles these key challenges and contributes to the pool of existing knowledge about TEGs dealing with four main topics: testing of thermoelectric generators, simulation of thermoelectric generating systems, design and production of power electronic converters for thermoelectric generators, and physical applications of thermoelectric generators. After an introduction to the physical phenomena underlying the operation of TEGs, this thesis describes the innovative test system built at the University of Glasgow to assess the performance of TEG devices in the ”real-world”. The fixture allows a single TEG device to be tested with thermal input power up to 1 kW and hot temperature up to 800◦C with minimal thermal losses and thermal shock; the mechanical clamping force can be adjusted up to 5 kN, and the temperatures are sensed by thermocouples placed directly on the TEGs surfaces. A computer program controls all the instruments in order to minimise errors and to aid accurate measurement and test repeatability. The test rig can measure four TEGs simultaneously, each one individually controlled and heated. This allows testing the performance of TEG arrays under mismatched conditions, e.g., dimensions, clamping force, temperature, etc. Under these circumstances experimental results and a mathematical analysis show that when in operation each TEG in the array will have a different electrical operating point at which maximum energy can be extracted and problems of decreased power output arise. This thesis provides the transient solution to the one-dimensional heat conduction equation with internal heat generation that describes the transfer and generation of heat throughout a thermoelectric device with dynamic exchange of heat through the hot and cold sides. This solution is then included in a model in which the Peltier effect, the thermal masses and the electrical behaviour of the system are also considered. The resulting model is created in Simulink and the comparison with experimental results from a TEG system confirms the accuracy of the simulation tool to predict the evolution of the thermoelectric system both in steady-state and during thermal or electrical transients. This thesis presents an investigation of the optimum electrical operating load to maximise the power produced by a TEG. Both fixed temperature difference and fixed thermal input power conditions are considered. Power electronic converters controlled by a Maximum Power Point Tracking (MPPT) algorithm are used to maximise the power transfer from the TEG to the load. The MPPT method based on the open-circuit voltage is arguably the most suitable for the almost linear electrical characteristic of TEGs. An innovative way to perform the open-circuit voltage measurement during the pseudo-normal operation of the power converter is presented. This MPPT technique is supported by theoretical analysis and used to control an efficient synchronous Buck-Boost converter capable of interfacing TEGs over a wide range of temperatures. The prototype MPPT converter is controlled by an inexpensive microcontroller, and a lead-acid battery is used to accumulate the harvested energy. Experimental results using commercial TEG devices demonstrate the ability of the MPPT converter to accurately track the maximum power point during steady-state and thermal transients. This thesis also presents two practical applications of TEGs. The first application exploits the thermal energy generated by a stove to concurrently produce electrical energy and heat water, while the second application recovers the heat energy rejected to ambient by a car’s exhaust gas system to generate electrical energy for battery charging.

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Naylor, Andrew J. « Towards highly-efficient thermoelectric power harvesting generators ». Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/366984/.

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Power harvesting from thermoelectric generators is considered as a viable route towards sustainable energy generation by the conversion of thermal gradients occuring naturally or from waste heat sources into useful electrical energy. This thesis investigates the electrodeposition of n-type binary, ternary and doped thermoelectric materials, with the aim of demonstrating that electrodeposition can be used as a cost-effective and simple technique to fabricate highly-efficient thermoelectric materials. In order to achieve this, the thermoelectric and electrical properties of such materials must be related to their microstructural properties. Therefore, a detailed and systematic study of their microstructural properties, including morphology, crystal structure, composition and crystallite size, is undertaken whilst also measuring the electrical and thermoelectric properties. It is found that the potential of the working electrode, employed as the substrate during the electrodeposition of bismuth telluride, is one of the most effective variables in the fabrication process. More anodic potentials such as 0 V vs. SCE offer the best microstructural and thermoelectric properties. The addition of a surfactant, sodium lignosulphonate, to the electrolyte further improves the microstructural properties of bismuth telluride thin films, by levelling the deposits and inducing greater crystallographic orientation in growth planes perpendicular to the substrate. This is believed to be preferential for improving thermoelectric properties. The electrodeposition of the ternary thermoelectric material bismuth tellurium selenide shows that the microstructural and hence the thermoelectric and electrical properties of the thin films can be optimised by use of more positive electrode potentials. The thin films fabricated exhibit a thermoelectric efficiency of up to two orders of magnitude greater than similar materials prepared by electrodeposition previously and equal efficiency to those prepared by methods which are more costly and difficult to undertake. Doping these materials with copper, by electrochemical means, further improves the thermoelectric efficiency by over another order of magnitude.

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Smith, Kevin D. « An investigation into the viability of heat sources for thermoelectric power generation systems / ». Online version of thesis, 2009. http://hdl.handle.net/1850/8266.

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Weinstein, Lee A. (Lee Adragon). « Improvements to solar thermoelectric generators through device design ». Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/85471.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2013.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 145-150).
A solar thermoelectric generator (STEG) is a device which converts sunlight into electricity through the thermoelectric effect. A STEG is nominally formed when a thermoelectric generator (TEG), a type of solid state heat engine, is placed between a solar absorber and a heat sink. When the solar absorber is illuminated by sunlight, it heats up and the TEG is subjected to a temperature gradient. Heat flows through the TEG, some of which is converted to electricity. Recent advancements have improved STEG efficiency considerably, however more work is required before STEGs will be able to compete commercially with other solar to electricity conversion technologies. This thesis explores two device level improvements to STEG systems. First, thin-film STEGs are explored as a method to potentially reduce the manufacturing costs of STEG systems. It is shown through modeling that thin-film STEGs have only a slight degradation in performance compared to bulk STEGs when identical materials properties are used. Two parameters are found which can guide device design for thin-film STEGs regardless of system size. Second, an optical cavity is investigated which can improve opto-thermal efficiency for STEGs or any other solar-thermal system. The cavity improves performance by specularly reflecting radiation from the absorber back to itself, reducing radiative losses. It is shown through modeling and with some preliminary experimental results that such a cavity has the potential to significantly improve the opto-thermal efficiency of solar-thermal systems and operate efficiently at high absorber temperatures without the use of extremely high optical concentration ratios.
by Lee A. Weinstein.
S.M.

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Sandoz-Rosado, Emil Jose. « Investigation and development of advanced models of thermoelectric generators for power generation applications / ». Online version of thesis, 2009. http://hdl.handle.net/1850/10795.

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McEnaney, Kenneth. « Modeling of solar thermal selective surfaces and thermoelectric generators ». Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/65308.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 101-107).
A thermoelectric generator is a solid-state device that converts a heat flux into electrical power via the Seebeck effect. When a thermoelectric generator is inserted between a solar-absorbing surface and a heat sink, a solar thermoelectric generator is created which converts sunlight into electrical power. This thesis describes the design and optimization of solar thermoelectric generators, with a focus on systems with high optical concentration which utilize multiple material systems to maximize efficiency over a large temperature difference. Both single-stage and cascaded (multi-stage) generators are considered, over an optical concentration range of 0.1 to 1000X. It is shown that for high-concentration Bi₂Te₃/skutterudite solar thermoelectric generators, conversion efficiencies of 13% are possible with current thermoelectric materials and selective surfaces. Better selective surfaces are needed to improve the efficiency of solar thermoelectric generators. In this thesis, ideal selective surfaces for solar thermoelectric generators are characterized. Non-ideal selective surfaces are also characterized, with emphasis on how the non-idealities affect the solar thernoelectric gencrator performance. Finally. the efficiency limit for solar thermoclectric generators with non-directional absorbers is presented.
by Kenneth McEnaney.
S.M.

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de, Leon Maria Theresa. « Efficiency improvement in MEMS thermoelectric generators employing solar concentration ». Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/368249/.

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Thermoelectric generators (TEGs) are devices that convert heat into electricity. The efficiency of thermoelectric generators depends on the temperature difference across the device, the average temperature of operation, and on the thermoelectric properties of the material. Most work on improving the TEG efficiency deals with improving the thermoelectric properties of the material. In this work, a method of improving the efficiency of the TEG by increasing the temperature difference is proposed. To accomplish this, a lens is used to concentrate solar radiation on the membrane of the TEG. By focusing solar radiation, the input heat flux increases; the temperature difference also increases; and the efficiency of the TEG improves as well. Two implementations of the TEG are explored. The first one involves a simple TEG implementation using a glass substrate with p-type polysilicon and aluminum as the thermoelectric materials. Although a significant amount of heat is lost through the substrate, test results still demonstrate that a significant improvement in the device efficiency as the input heat flux is increased. The second implementation involves fabricating the TEG on a SOI substrate where the buried oxide layer is not etched and a thin portion of the handle layer is retained to provide additional structural stability. The thermoelectric materials for this TEG implementation are p-type silicon and aluminum. Although this implementation performs poorly than when both handle and buried oxide layers of the SOI under the membrane and thermoelements are etched, a SOI wafer with a thinner device layer is used to compensate for the losses. The fabricated TEGs are characterized using a laser test set-up where the input power is varied up to 1 W and the spot size diameter is fixed at 1 mm. Measurement results on fabricated TEGs with 1 W input power exhibited a temperature difference of up to 226˚C, open-circuit voltage of 3 V, output power of 25 μW, and about 10 times improvement in conversion efficiency. The fabricated TEGs are also tested using a solar simulator and three lenses of different diameters to emulate conditions where the device would be deployed as a solar TEG. Using a 50.8 mm diameter lens, the largest temperature difference measured is 18˚C, which gives an open-circuit voltage and output power of 803 mV and 431 nW, respectively.

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Rahman, Mahmudur. « The application of thermoelectric generators as remote power sources ». Thesis, University of Manchester, 1993. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.645193.

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Sivapurapu, Sai Vinay Kumar Plummer Mitty Charles. « Preliminary design of a cryogenic thermoelectric generator ». [Denton, Tex.] : University of North Texas, 2007. http://digital.library.unt.edu/permalink/meta-dc-3612.

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Gadea, Gerard. « Integration of Si/Si-Ge nanostructures in micro-thermoelectric generators ». Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/459243.

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Silicon and silicon-germanium nanostructures were grown, integrated, optimized and characterized for their application in thermoelectric generation. Specifically two kinds of nanostructures were worked: silicon and silicon-germanium nanowire arrays (Si/Si-Ge NW) and polycrystalline silicon nanotube fabrics (pSi NT). The results are dived in four chapters. Chapters 3, 4 and 5 deal with Si/Si-Ge NWs, while chapter 6 presents the pSi NT fabrics. In Chapter 3 the growth and integration of Si/Si-Ge NWs was studied, in order to optimize their properties for thermoelectric application in micro-thermoelectric generators (µTEG). First, the methods for depositing gold nanoparticles prior to NW growth were studied. Second, the growth of NWs from the gold nanoparticles in a Chemical Vapour Deposition (CVD) process was comprehensively studied and optimized for subsequent integration of NWs in µTEGs, both of Si and Si-Ge. All important properties – NW length, diameter, density, doping and alignment – could be controlled by tuning the seeding gold nanoparticles and the process conditions, namely temperature, pressure, flows of reactants and growth time. Finally, integration was demonstrated in micro-structures for thermoelectric generation and characterization. The optimization process yielded to fully integrated thermoelectric Si/Si-Ge NW arrays with diameters and densities of ~100 nm and 5 NW/µm2 respectively. In Chapter 4 the Si NWs were thermoelectrically characterized. The Seebeck coefficient, electrical conductivity and thermal conductivity of arrays and single Si-NWs were measured in microstructures devoted to characterization comprising NWs integrated as in final µTEG application. Additionally a novel atomic force microscope based method for determination of thermal conductivity was explored. Then the results were discussed comparing them with existing literature. A ZT of 0.022 was found at room temperature, revealing an improvement of factor 2-3 with respect to bulk. In Chapter 5 The harvesting capabilities of µTEGs with integrated Si/Si-Ge NWs was assessed. The thermal gradient and the power of the µTEGs was assessed for two generation of devices and for two thermoelectric materials, namely Si and Si-Ge NWs, which were integrated for the first time in functional generators. Also a study on heat sinking and convection effects was conducted adding insight towards further device improvement. Finally, the results were discussed and compared with literature. The maximum power densities attained were 4.5 µW/cm2 for the Si NWs and 4.9 µW/cm2 for the Si-Ge NWs while harvesting over surfaces at 350 ºC. Chapter 6 deals with pSi NT fibers. First this new material concept and the growth route are presented, showing the fabrication steps and the control of the resulting properties by CVD method. Then the material is thermoelectrically characterized, by measuring its Seebeck coefficient and electrical and thermal conductivities up to 450 ºC. A ZT of 0.12 was found, doubling the optimally doped bulk at this temperature. Finally a proof of concept was demonstrated by assessing the thermal harvesting capabilities of the material on top of hot surfaces. A maximum of 3.5 mW/cm2 was attained at 650 ºC.
Los materiales termoeléctricos permiten la conversión de calor a electricidad y viceversa. Esto permite explotar el efecto termoeléctrico en generadores termoeléctricos, capaces de extraer energía térmica de fuentes calientes y convertirla a electricidad útil. Estos generadores presentan grandes ventajas, como su falta de piezas móviles – y por ende necesidad de mantenimiento alguna – y su total escalabilidad, que permite cambiar su tamaño sin afectar su rendimiento. Esto los hace obvios candidatos para la alimentación y carga de dispositivos portátiles y situados lugares de difícil acceso. A pesar de ello, su uso no está muy extendido debido a que su relación eficiencia-coste es baja en comparación a otros métodos capaces de suplir las funciones de alimentación – como la sustitución periódica de baterías – o de conversión térmica-eléctrica – como las turbinas de vapor. Los materiales termoeléctricos suelen ser o eficientes y caros (como el Bi2Te3 usado en los módulos comerciales) o ineficientes y de bajo coste (como el silicio, barato por su abundancia ya que supone un 28% de la corteza terrestre). En este trabajo se han crecido nanostructuras de silicio y silicio-germano, con dimensiones en el orden de los 100 nm. Los nanomateriales presentan propiedades termoeléctricas mejoradas respecto a sus contrapartes macroscópicas. Gracias a la nanoestructuración pues, se ha abordado del problema de eficiencia-coste por dos vertientes: • En el caso del silicio – normalmente un mal termoeléctrico debido a su alta conductividad térmica – se ha habilitado su uso como termoeléctrico al crecerlo en forma de nanohilos cristalinos y nanotubos de silicio policristalino. • En el caso de silicio-germano – que ya es un buen termoeléctrico para uso en altas temperaturas – se ha aumentado su eficiencia aún más, creciéndolo en forma de nanohilos. Yendo más allá de la síntesis, los nanohilos de silicio/silicio-germano se han optimizado, caracterizado en integrado en gran número micro-generadores termoeléctricos de 1 mm2 de superficie, pensados para la alimentación de pequeños dispositivos y circuitos integrados. Respecto a los nanotubos de Si, estos se han obtenido en densas fibras macroscópicas aptas para su aplicación directa como generadores termoeléctricos de gran área. Cabe mencionar que ambos nanomateriales – así como los microgeneradores basados en nanohilos – fueron obtenidos mediante técnicas actualmente utilizadas para la fabricación de circuitos integrados, pensando en la escalabilidad del proceso para su aplicación. El trabajo presentado en esta tesis consiste en el crecimiento, optimización, estudio e integración de nanostructuras de Si/Si-Ge para su aplicación en generación termoeléctrica. En los Capítulos 1 y 2 se pone un marco a los materiales tratados y su aplicación y se describen los métodos utilizados, respectivamente. Los resultados se han dividido en cuatro capítulos. En los Capítulos 3, 4 y 5 se tratan los nanohilos abordando su crecimiento, caracterización y aplicación en microgeneradores, respectivamente. En el Capítulo 6 se tratan las fibras de nanotubos, integrando todo el estudio en el mismo capítulo. Finalmente en el Capítulo 7 se muestran las conclusiones, resumiendo los resultados e indicando la relevancia del trabajo.

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Rostek, Raimar [Verfasser], et Peter [Akademischer Betreuer] Woias. « Electrochemical deposition as a fabrication method for micro thermoelectric generators ». Freiburg : Universität, 2016. http://d-nb.info/1122647638/34.

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Li, Xinjie. « Concentrated Solar Thermoelectric Generators Based on V-shaped Metallic Couples ». University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613752123514427.

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Fransson, Erik, et Daniel Olsson. « Thermoelectric Generators : A comparison of electrical power outputs depending on temperature ». Thesis, Högskolan Dalarna, Institutionen för information och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:du-38031.

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Today many processes generate a lot of waste heat, for example industries or cars. One way to make this thermal energy useful is to transform it into electrical energy with a thermoelectric generator (TEG) or thermoelectric cooler (TEC). This technology is not used in any large scale today, but a lot of research is being done on the subject. The technology is based on the Seebeck effect and uses a temperature difference between two sides of an element to generate an electrical current. The reason that the research has gained more attention in recent years is because of the increasing electricity prices and the diminishing natural resources. Other benefits are that they run quietly and do not demand much maintenance.Another area where this technology could be useful is in off-grid cabins where it is easy to generate a lot of thermal energy by burning wood, but electrical energy is in high demand.In this thesis two different types of TEGs and one type of TEC are tested to investigate how much power they generate at different temperature differences, how well they meet the specified values in their respective data sheet and what their power per euro value is. For this, an experimental setup was made with:- An induction plate to increase the temperature on the hot side.- A CPU-fan, to reduce the temperature on the cold side.- Two temperature sensors (one for measuring the hot temperature and one for the cold one).- An electric circuit featuring a voltmeter, an amperemeter and an adjustable resistor (rheostat).The results show that, for this experiment the highest received power (6,38 W) comes from the medium-priced element but the highest power per euro comes from the lowest priced element (1,16 W/€). A quality problem for the lowest priced element was that parts of the solder melted when the temperature exceeded 225 °C. Another problem was that the induction plate was unable to provide enough heat for the most expensive of the elements to reach the temperature for which the retailer supplies their measured data.

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Sivapurapu, Sai Vinay Kumar. « Preliminary design of a cryogenic thermoelectric generator ». Thesis, University of North Texas, 2007. https://digital.library.unt.edu/ark:/67531/metadc3612/.

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A cryogenic thermoelectric generator is proposed to increase the efficiency of a vehicle propulsion system that uses liquid nitrogen as its fuel. The proposed design captures some of the heat required for vaporizing or initial heating of the liquid nitrogen to produce electricity. The thermoelectric generator uses pressurized liquid nitrogen as its cold reservoir and ambient air as the high-temperature reservoir to generate power. This study concentrated on the selection of thermoelectric materials whose properties would result in the highest efficiency over the operating temperature range and on estimating the initial size of the generator. The preliminary selection of materials is based upon their figure of merit at the operating temperatures. The results of this preliminary design investigation of the cryogenic thermoelectric generator indicate that sufficient additional energy can be used to increase overall efficiency of the thermodynamic cycle of a vehicle propulsion system.

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Isotta, Eleonora. « Nanostructured thermoelectric kesterite Cu2ZnSnS4 ». Doctoral thesis, Università degli studi di Trento, 2021. http://hdl.handle.net/11572/315174.

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To support the growing global demand for energy, new sustainable solutions are needed both economically and environmentally. Thermoelectric waste heat recovery and energy harvesting could contribute by increasing industrial process efficiency, as well as powering stand-alone devices, microgenerators, and small body appliances.The structural complexity of quaternary chalcogenide materials provides an opportunity for engineering defects and disorder, to modify and possibly improve specific properties. Cu2ZnSnS4 (CZTS, often kesterite), valued for the abundance and non-toxicity of the raw materials, seems particularly suited to explore these possibilities, as it presents several structural defects and polymorphic phase transformations. The aim of this doctoral work is to systematically investigate the effects of structural polymorphism, disorder, and defects on the thermoelectric properties of CZTS, with particular emphasis to their physical origin. A remarkable case is the order-disorder transition of tetragonal CZTS, which is found responsible for a sharp enhancement in the Seebeck coefficient due to a flattening and degeneracy of the electronic energy bands. This effect, involving a randomization of Cu and Zn cations in certain crystallographic planes, is verified in bulk and thin film samples, and applications are proposed to exploit the reversible dependence of electronic properties on disorder. Low-temperature mechanical alloying is instead discovered stabilizing a novel polymorph of CZTS, which disordered cubic structure is studied in detail, and proposed deriving from sphalerite-ZnS. The total cation disorder in this compound provides an uncommon occurrence in thermoelectricity: a concurrent optimization of Seebeck coefficient, electrical and thermal conductivity. These findings, besides providing new and general understanding of CZTS, can cast light on profitable mechanisms to enhance the thermoelectric performance of semiconducting chalcogenides, as well as delineate alternative and fruitful applications.

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Isotta, Eleonora. « Nanostructured thermoelectric kesterite Cu2ZnSnS4 ». Doctoral thesis, Università degli studi di Trento, 2021. http://hdl.handle.net/11572/315174.

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To support the growing global demand for energy, new sustainable solutions are needed both economically and environmentally. Thermoelectric waste heat recovery and energy harvesting could contribute by increasing industrial process efficiency, as well as powering stand-alone devices, microgenerators, and small body appliances. The structural complexity of quaternary chalcogenide materials provides an opportunity for engineering defects and disorder, to modify and possibly improve specific properties. Cu2ZnSnS4 (CZTS, often kesterite), valued for the abundance and non-toxicity of the raw materials, seems particularly suited to explore these possibilities, as it presents several structural defects and polymorphic phase transformations. The aim of this doctoral work is to systematically investigate the effects of structural polymorphism, disorder, and defects on the thermoelectric properties of CZTS, with particular emphasis to their physical origin. A remarkable case is the order-disorder transition of tetragonal CZTS, which is found responsible for a sharp enhancement in the Seebeck coefficient due to a flattening and degeneracy of the electronic energy bands. This effect, involving a randomization of Cu and Zn cations in certain crystallographic planes, is verified in bulk and thin film samples, and applications are proposed to exploit the reversible dependence of electronic properties on disorder. Low-temperature mechanical alloying is instead discovered stabilizing a novel polymorph of CZTS, which disordered cubic structure is studied in detail, and proposed deriving from sphalerite-ZnS. The total cation disorder in this compound provides an uncommon occurrence in thermoelectricity: a concurrent optimization of Seebeck coefficient, electrical and thermal conductivity. These findings, besides providing new and general understanding of CZTS, can cast light on profitable mechanisms to enhance the thermoelectric performance of semiconducting chalcogenides, as well as delineate alternative and fruitful applications.

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Mirando, Francesco. « Micro-fabrication and characterization of highly doped silicon-germanium based thermoelectric generators ». Thesis, University of Glasgow, 2018. http://theses.gla.ac.uk/30596/.

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Over the last decades of research on sustainable energy, thermoelectric generation has been identified as a potential energy harvesting solution for a wide range of applications. Nowadays, the commercial thermoelectric technology is almost entirely based on tellurium alloys, it mainly addresses room temperature applications and it is not compatible with MEMS and CMOS processing. In this work, silicon-germanium based micro-devices have been designed, developed and characterized with the aim of addressing the heat recovery needs of the automotive industry. The micro-scale of the fabricated devices, together with the full compatibility with silicon micro-processing, also profiles an interesting potential for application in the autonomous sensor field. Most importantly, the configuration and the fabrication processes of such silicon-based generators constitute a platform to transfer the results of decades of promising material investigations and engineering into practical micro-scaled thermoelectric generators. The room temperature characterization of the manufactured micro-generators revealed power factors up to 13.9x10-3 μW/(cm2K2) and maximum output power density up to 24.7 μW/cm2. In such temperature range, the micro-devices manufactured in this work are still not as performing as the state-of-the-art bismuth-telluride based technology. However, at around 300 C, the developed micro-modules are predicted to produce a maximum power output of 1.2-1.5mW under 10 C temperature gradient, which corresponds to 35-45% of the room temperature performance of the only commercial bismuth telluride based micro-devices. The results show that silicon-germanium micro-modules could potentially compete with the state-of-the-art commercial micro-devices, being better performing at higher temperature, but also offering the advantage of being a sustainable MEMS and CMOS compatible option for autonomous sensors integration.

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Davenport, Bradley P. « Advanced thermophotovoltaic cells modeling, optimized for use in rRadioisotope Thermoelectric Generators (RTGS) for Mars and deep space missions / ». Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Jun%5FDavenport.pdf.

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Hausgen, Paul E. « A thermal analysis of an alkali metal thermal to electric converter with geometrically designed interior surfaces exhibiting directionally dependent radiative properties ». Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/16701.

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Comamala, Laguna Martí. « Development and characterization of thermoelectric generators for thermal energy recovery from reciprocating internal combustion engines ». Doctoral thesis, Universitat de Girona, 2019. http://hdl.handle.net/10803/668142.

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Since the beginnings of the automotive driven with internal combustion engines all the cycles used in the alternative motors share a thermal characteristic, a large amount of heat released by the fuel is lost in the form of hot gases that exits from the exhaust system. This research has intensified in recent years due to the consequences of climate change, and above all, the Administration pressure on automotive manufacturers regarding the reduction of pollutant emissions, especially CO2. The system proposed in this thesis uses the advantages that thermoelectricity can provide, a thermoelectric generator can meet the requirements mentioned above. The scope of application of thermoelectric materials is very large, from temperature sensors, through portable coolers, to solar power generators. In general, these applications can be classified according to the direction of the energy conversion. While the Peltier effect is used in solid-state refrigeration, the Seebeck effect is responsible for converting the temperature differences into electrical voltage in energy recovery systems. The Seebeck effect is what our want to produce in a vehicle when you want to recover heat energy, because thanks to the thermoelectric materials the electricity produced can be injected into the vehicle's electric system by reducing the load of the alternator and therefore the overall consumption of the thermal engine. This doctoral thesis addresses aspects that until now had been little explored by the researchers: (i) the effects on the behavior of the motor when a new system is introduced in the exhaust line, (ii) the use of software sufficiently powerful to simulate the integration of the thermoelectric generator into a complete vehicle and (iii) the experimental quantification of the consumption savings when thermoelectric generators are incorporated
L’aprofitament energètic de la calor residual dels gasos d’escapament és una fita perseguida per molts fabricants i investigadors en el camp de l’automoció. Aquesta recerca s’ha intensificat en els últims anys motivada per les conseqüències del canvi climàtic, i sobretot, per la pressió de les administracions sobre els fabricants d’automoció pel que fa a la disminució de les emissions contaminants, especialment del CO2. El sistema proposat en aquesta tesi utilitza els avantatges que pot proporcionar la termoelectricitat, considerant que un generador termoelèctric pot satisfer els requisits esmentats anteriorment. Aquesta tesi doctoral aborda aspectes que fins ara havien estat molt poc explorats pels investigadors : (i) els efectes sobre el comportament del motor quan s’introdueix un sistema nou a la línia d’escapament, (ii) la utilització de software suficientment potent per simular la integració del generador termoelèctric en un vehicle complet, i (iii) la quantificació experimental de l’estalvi de consum quan s’incorporen generadors termoelèctrics

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Edvinsson, Nils. « Energy harvesting power supply for wireless sensor networks : Investigation of piezo- and thermoelectric micro generators ». Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-210429.

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Computers and their constituent electronics continue to shrink. The same amount of work can be done with increasingly smaller and cheaper components that need less power to function than before. In wireless sensor networks, the energy needed by one sensor node borders the amount that is already present in its immediate surroundings. Equipping the electronics with a micro generator or energy harvester gives the possibility that it can become self-sufficient in energy. In this thesis two kinds of energy harvesters are investigated. One absorbs vibrations and converts them into electricity by means of piezo-electricity. The other converts heat flow through a semiconductor to electricity, utilizing a thermoelectric effect. Principles governing the performance, actual performance of off-the-shelf components and design considerations of the energy harvester have been treated. The thermoelectric micro generator has been measured to output power at 2.7 mW and 20°C with a load of 10 W. The piezoelectric micro generator has been measured to output power at 2.3 mW at 56.1 Hz, with a mechanical trim weight and a load of 565 W. In these conditions the power density of the generators lies between 2-3 W/m2.

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Davenport, Bradley P. « Advanced thermophotovoltaic cells modeling, optimized for use in radioisotope thermoelectric generators (RTGS) for Mars and deep space missions ». Thesis, Monterey California. Naval Postgraduate School, 2004. http://hdl.handle.net/10945/1170.

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Approved for public release; distribution is unlimited.
Thermophotovoltaic cells are a good candidate for use in high efficiency radioisotope thermoelectric generator (RTG) power devices for deep space missions. This thesis examines the use of Silvaco Virtual Wafer Fabrication Software as a tool for designing and optimizing TPV cells for different possible spectra. It gives results for GaSb and InGaAs cells optimized to the AM0 spectrum which closely match published data as well as hypothetical cells optimized to the spectrum of a 1300K blackbody.
Ensign, United States Navy

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Deshpande, Samruddhi Aniruddha. « Numerical Investigation of Various Heat Transfer Performance Enhancement Configurations for Energy Harvesting Applications ». Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/72129.

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Conventional understanding of quality of energy suggests that heat is a low grade form of energy. Hence converting this energy into useful form of work was assumed difficult. However, this understanding was challenged by researchers over the last few decades. With advances in solar, thermal and geothermal energy harvesting, they believed that these sources of energy had great potential to operate as dependable avenues for electrical power. In recent times, waste heat from automobiles, oil and gas and manufacturing industries were employed to harness power. Statistics show that US alone has a potential of generating 120,000 GWh/year of electricity from oil , gas and manufacturing industries, while automobiles can contribute upto 15,900 GWh/year. Thermoelectric generators (TEGs) can be employed to capture some of this otherwise wasted heat and to convert this heat into useful electrical energy. This field of research as compared to gas turbine industry has emerged recently over past 30 decades. Researchers have shown that efficiency of these TEGs modules can be improved by integrating heat transfer augmentation features on the hot side of these modules. Gas turbines employ advanced technologies for internal and external cooling. These technologies have applications over wide range of applications, one of which is thermoelectricity. Hence, making use of gas turbine technologies in thermoelectrics would surely improve the efficiency of existing TEGs. This study makes an effort to develop innovative technologies for gas turbine as well as thermoelectric applications. The first part of the study analyzes heat transfer augmentation from four different configurations for low aspect ratio channels and the second part deal with characterizing improvement in efficiency of TEGs due to the heat transfer augmentation techniques.
Master of Science

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Brogan, Quinn Lynn. « Low Power IC Design with Regulated Output Voltage and Maximum Power Point Tracking for Body Heat Energy Harvesting ». Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/81549.

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As wearable technology and wireless sensor nodes become more and more ubiquitous, the batteries required to power them have become more and more unappealing as they limit lifetime and scalability. Energy harvesting from body heat provides a solution to these limitations. Energy can be harvested from body heat using thermoelectric generators, or TEGs. TEGs provide a continuous, scalable, solid-state energy source ideal for wearable and wireless electronics and sensors. Unfortunately, current TEG technology produces low power (< 1 mW) at a very low voltage (20-90 mV) and require the load to be matched to the TEG internal resistance for maximum power transfer to occur. This thesis research proposes a power management integrated circuit (PMIC) that steps up ultralow voltages generated by TEGs to a regulated 3 V, while matching the internal resistance. The proposed boost converter aims to harvest energy from body heat as efficiently and flexibly as possible by providing a regulated 3 V output that can be used by a variable load. A comparator-based burst mode operation affords the converter a high conversion ratio at high efficiency, while fractional open circuit voltage maximum power point tracking ensures that the controller can be used with a variety of TEGs and TEG setups. This control allows the converter to boost input voltages as low as 50 mV, while matching a range of TEG internal source resistances in one stage. The controller was implemented in 0.25 µm CMOS and taped out in February 2016. Since these fabricated chips will not be completed and delivered until May 2016, functionality has only been verified through simulation. Simulation results are promising and indicate that the peak overall efficiency is 81% and peak low voltage, low power efficiency is 73%. These results demonstrate the the proposed converter can achieve overall efficiencies comparable to current literature and low power efficiencies better than similar wide range converters in literature.
Master of Science

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Heghmanns, Alexander, et Michael Beitelschmidt. « Mehrkriterielle Parameteroptimierung eines Thermoelektrischen Generators ». Universitätsbibliothek Chemnitz, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-142372.

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Aufgrund von steigenden Energiekosten und einer sukzessive steigenden öffentlichen sowie politischen Forderung nach Umweltbewusstsein und Nachhaltigkeit, ist die Effizienzsteigerung von Gesamtsystemen einer der treibenden Kräfte für innovative, technologische Neuheiten geworden. Besonders bei der Entwicklung von verbrennungsmotorisch angetriebenen Fahrzeugen wurden z.B. durch die Hybridisierung von Antriebssträngen, die die Rekuperation von kinetischer Energie ermöglichen, Technologien zur Energieeinsparung etabliert. Da bei Verbrennungsmotoren ein hoher Anteil der im Kraftstoff gespeicherten Energie technologiebedingt als Abwärme im Abgas verloren geht, bietet die Wärmerekuperation ein weiteres hohes Potential für weitere Einsparungen. Diese ist z.B. mit Hilfe von thermoelektrischen Generatoren (TEG) möglich, die einen Wärmestrom direkt in elektrische Energie umwandeln. Zur effizienten TEG-Systemgestaltung ist ein hoher Temperaturgradient über dem thermoelektrisch aktivem Material notwendig, der wiederum zu kritischen thermomechanischen Spannungen im Bauteil führen kann. Diese werden zum einen durch die unterschiedlichen Temperaturausdehnungskoeffizienten der verschiedenen Materialien und zum anderen durch die mechanische Anbindung auf der heißen und kalten Seite des TEG verursacht. Somit liegt ein Zielkonflikt zwischen dem thermoelektrischen Systemwirkungsgrad und der mechanischen Festigkeit des Bauteils vor. In dieser Arbeit wird mit Hilfe einer mehrkriteriellen Parameteroptimierung eines vollparametrisierten FE-Modells des TEG in ANSYS WORKBENCH eine Methode vorgestellt, den thermoelektrischen Wirkungsgrad bei gleichzeitiger Reduktion der thermomechanischen Spannungen zu optimieren. Zur Optimierung kommt dabei ein genetischer Algorithmus der MATLAB GLOBAL OPTIMIZATION TOOLBOX zum Einsatz. Der Modellaufbau wird in ANSYS WORKBENCH mit der Makro-Programmiersprache JSCRIPT realisiert. Als Ziel- und Bewertungsfunktionen wird die mechanische Belastung jedes Bauteils im TEG ausgewertet und dessen elektrische Leistungsdichte berechnet. Die Ergebnisse zeigen, dass mit Hilfe der vorgestellten Methodik eine paretooptimale Lösung gefunden werden kann, die den gestellten Anforderungen entspricht.

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Palu, Ivo. « Impact of wind parks on power system containing thermal power plants = Tuuleparkide mõju soojuselektrijaamadega energiasüsteemile / ». Tallinn : TUI Press, 2009. http://digi.lib.ttu.ee/i/?443.

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Pandit, Jaideep. « Numerical and Experimental Design of High Performance Heat Exchanger System for A Thermoelectric Power Generator for Implementation in Automobile Exhaust Gas Waste Heat Recovery ». Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/47919.

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The effects of greenhouse gases have seen a significant rise in recent years due to the use of fossil fuels like gasoline and diesel. Conversion of the energy stored in these fossil fuels to mechanical work is an extremely inefficient process which results in a high amount of energy rejected in the form of waste heat. Thermoelectric materials are able to harness this waste heat energy and convert it to electrical power. Thermoelectric devices work on the principle of the Seebeck effect, which states that if two junctions of dissimilar materials are at different temperatures, an electrical potential is developed across them. Even though these devices have small efficiencies, they are still an extremely effective way of converting low grade waste heat to usable electrical power. These devices have the added advantage of having no moving parts (solid state) which contributes to a long life of the device without needing much maintenance. The performance of thermoelectric generators is dependent on a non-dimensional figure of merit, ZT. Extensive research, both past and ongoing, is focused on improving the thermoelectric generator's (TEG's) performance by improving this figure of merit, ZT, by way of controlling the material properties. This research is usually incremental and the high performance materials developed can be cost prohibitive. The focus of this study has been to improve the performance of thermoelectric generator by way of improving the heat transfer from the exhaust gases to the TEG and also the heat transfer from TEG to the coolant. Apart from the figure of merit ZT, the performance of the TEG is also a function of the temperature difference across it, By improving the heat transfer between the TEG and the working fluid, a higher temperature gradient can be achieved across it, resulting in higher heat flux and improved efficiency from the system. This area has been largely neglected as a source of improvement in past research and has immense potential to be a low cost performance enhancer in such systems. Improvements made through this avenue, also have the advantage of being applicable regardless of the material in the system. Thus these high performance heat exchangers can be coupled with high performance materials to supplement the gains made by improved figure of merits. The heat exchanger designs developed and studied in this work have taken into account several considerations, like pressure drop, varying engine speeds, location of the system along the fuel path, system stability etc. A comprehensive treatment is presented here which includes 3D conjugate heat transfer modeling with RANS based turbulence models on such a system. Various heat transfer enhancement features are implemented in the system and studied numerically as well as experimentally. The entire system is also studied experimentally in a scaled down setup which provided data for validation of numerical studies. With the help of measured and calculated data like temperature, ZT etc, predictions are also presented about key metrics of system performance.
Ph. D.

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Sadler, Zachary James. « Design and Analysis of Compressed Air Power Harvesting Systems ». BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/7052.

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Procedure for site discovery, system design, and optimization of power harvesting systems is developed with an emphasis on application to air compressors. Limitations for the usage of infrared pyrometers is evaluated. A system of governing equations for thermoelectric generators is developed. A solution method for solving the system of equations is created in order to predict power output from the device. Payback analysis is proposed for determining economic viability. A genetic algorithm is used to optimize the power harvesting system payback with changing quantities and varieties of thermoelectric generators, as well as the back work put into cooling the thermoelectric generators. Experimental data is taken for laboratory simulation of a power harvesting system under varying resistive load and thermal conductances in order to confirm the working model. A power harvester is designed for and installed on a consumer grade portable air compressor. Experimental data is compared against the model's prediction. As a case study, a system is designed for a water-cooled power harvesting system. Thermoelectric generator power harvesters are found to be economically infeasible for typical installations at current energy prices. Changes in parameters which would increase economic feasibility of the power harvesting system are discussed.

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Hodges, Amelia Lynn. « Investigation of antennas and energy harvesting methods for use with a UHF microtransceiver in a biosensor network ». Thesis, Kansas State University, 2013. http://hdl.handle.net/2097/16218.

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Master of Science
Department of Electrical and Computer Engineering
William B. Kuhn
This work was a part of NASA EPSCoR Project NNX11AM05A: Biosensor Networks and Telecommunication Subsystems for Long Duration Missions, EVA Suits, and Robotic Precursor Scout Missions. The project’s main goal is the development of a wireless sensor network inside an astronaut’s spacesuit. Antennas are essential components in a wireless network. Since this antenna will be used inside the spacesuit it is important to consider both the physical size limitations and the desired antenna polarization. After exploring the WWVB radio station antenna which provides the preferred vertical polarization and has a suitable aspect ratio, the top hat antenna seemed promising for intrasuit communication. The design of a top hat antenna is outlined. Then, the antennas were tested using 433 MHz radios in a full scale model spacesuit. This spacesuit was designed specifically to model the behavior of aluminized mylar in the real suit. Test results support the feasibility of an intrasuit wireless network. If a gateway radio is placed on the chest or back, a sensor could be placed anywhere on the body and provide an adequate signal. These initial tests did not include a matching network, but the additional link-margin afforded by a matching network, even an imperfect match, is considered. Energy harvesting is explored as an alternative to batteries powering the intrasuit radio. In the oxygen rich environment of a spacesuit, even the smallest spark can be catastrophic. A variety of energy harvesting options are explored with a focus on thermal energy harvesting. The temperature difference between the human skin and the astronaut’s Liquid Cooling and Ventilation Garment can be used to produce a small voltage. To increase the voltage a step-up converter is implemented. Final integration of the two systems with a biosensor is left for on-going work in the three year NASA project.

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Faghani, Farshad. « Thermal conductivity Measurement of PEDOT:PSS by 3-omega Technique ». Thesis, Linköpings universitet, Fysik och elektroteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-63317.

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Conducting polymers (CP) have received great attention in both academic and industrial areas in recent years. They exhibit unique characteristics (electrical conductivity, solution processability, light weight and flexibility) which make them promising candidates for being used in many electronic applications. Recently, there is a renewed interest to consider those materials for thermoelectric generators that is for energy harvesting purposes. Therefore, it is of great importance to have in depth understanding of their thermal and electrical characteristics. In this diploma work, the thermal conductivity of PEDOT:PSS is investigated by applying 3-omega technique which is accounted for a transient method of measuring thermal conductivity and specific heat. To validate the measurement setup, two benchmark substrates with known properties are explored and the results for thermal conductivity are nicely in agreement with their actual values with a reasonable error percentage. All measurements are carried out inside a Cryogenic probe station with vacuum condition. Then a bulk scale of PEDOT:PSS with sufficient thickness is made and investigated. Although, it is a great challenge to make a thick layer of this polymer since it needs to be both solid state and has as smooth surface as possible for further gold deposition. The results display a thermal conductivity range between 0.20 and 0.25 (W.m-1.K-1) at room temperature which is a nice approximation of what has been reported so far. The discrepancy is mainly due to some uncertainty about the exact value of temperature coefficient of resistance (TCR) of the heater and also heat losses especially in case of heaters with larger surface area. Moreover, thermal conductivity of PEDOT:PSS is studied over a wide temperature band ranging from 223 - 373 K.

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Carstens, Jan Hendrik Hermann [Verfasser], Clemens [Akademischer Betreuer] Gühmann, Clemens [Gutachter] Gühmann, Hans-Christian [Gutachter] Reuss et Thomas [Gutachter] Schauer. « Control and optimization of a DC-DC converter for thermoelectric generators / Jan Hendrik Hermann Carstens ; Gutachter : Clemens Gühmann, Hans-Christian Reuss, Thomas Schauer ; Betreuer : Clemens Gühmann ». Berlin : Technische Universität Berlin, 2016. http://d-nb.info/1156179971/34.

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Sklar, Akiva A. « A Numerical Investigation of a Thermodielectric Power Generation System ». Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/14020.

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The performance of a novel micro-thermodielectric power generation device (MTDPG) was investigated in order to determine if thermodielectric power generation can compete with current portable power generation technologies. Thermodielectric power generation is a direct energy conversion technology that converts heat directly into high voltage direct current. It requires dielectric (i.e., capacitive) materials whose charge storing capabilities are a function of temperature. This property is exploited by heating these materials after they are charged; as their temperature increases, their charge storage capability decreases, forcing them to eject a portion of their surface charge to an appropriate electronic storage device. Previously, predicting the performance of a thermodielectric power generator was hindered by a poor understanding of the materials thermodynamic properties and the affect unsteady heat transfer losses have on system performance. In order to improve predictive capabilities in this study, a thermodielectric equation of state was developed that describes the relationship between the applied electric field, the surface charge stored by the thermodielectric material, and its temperature. This state equation was then used to derive expressions for the material's thermodynamic states (internal energy, entropy), which were subsequently used to determine the optimum material properties for power generation. Next, a numerical simulation code was developed to determine the heat transfer capabilities of a micro-scale parallel plate heat recuperator (MPPHR), a device designed specifically to a) provide the unsteady heating and cooling necessary for thermodielectric power generation and b) minimize the unsteady heat transfer losses of the system. The previously derived thermodynamic equations were then incorporated into the numerical simulation code, creating a tool capable of determining the thermodynamic performance of an MTDPG, in terms of the thermal efficiency, percent Carnot efficiency, and energy/power density, when the material properties and the operating regime of the MPPHR were varied. The performance of the MTDPG was optimized for an operating temperature range of 300 500 K. The optimization predicted that the MTDPG could provide a thermal efficiency of 29.7 percent. This corresponds to 74.2 percent of the Carnot efficiency. The power density of this MTDPG depends on the operating frequency and can exceed 1,000,000 W/m3.

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Namakian, Mohsen. « Mild Hybrid System in Combination with Waste Heat Recovery for Commercial Vehicles ». Thesis, Linköpings universitet, Maskinkonstruktion, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-93997.

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Performance of two different waste heat recovery systems (one based on Rankine cycle and the other one using thermoelectricity) combined with non-hybrid, mild-hybrid and full hybrid systems are investigated. The vehicle under investigation was a 440hp Scania truck, loaded by 40 tons. Input data included logged data from a long haulage drive test in Sweden.All systems (waste heat recovery as well as hybrid) are implemented and simulated in Matlab/Simulink. Almost all systems are modeled using measured data or performance curves provided by one manufacturer. For Rankine system results from another investigation were used.Regardless of practical issues in implementing systems, reduction in fuel consumption for six different combination of waste heat recovery systems and hybrid systems with different degrees of hybridization are calculated. In general Rankine cycle shows a better performance. However, due to improvements achieved in laboratories, thermoelectricity could also be an option in future.This study focuses on “system” point of view and therefore high precision calculations is not included. However it can be useful in making decisions for further investigations.

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Véras, Júlio Cezar de Cerqueira. « Análise experimental dos efeitos termoelétricos em geradores termoelétricos ». Universidade Federal da Paraíba, 2014. http://tede.biblioteca.ufpb.br:8080/handle/tede/5303.

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Made available in DSpace on 2015-05-08T14:57:19Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1298323 bytes, checksum: 6a19c3b38cf846b711c2c52ac67ab30a (MD5) Previous issue date: 2014-11-28
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
A thermoelectric generator is a solid-state temperature dependent device that provide power generation on thermoelectric conversion. For that, the thermoelectric modules needs a temperature difference to ensure the thermoelectric conversion process. However, being subject to temperature variations may compromise the thermoelectric generator lifetime. Thus, in order to evaluate the temperature variation (thermal cycling) that the thermoelectric generators are exposed, this work has proposed an experimental platform that submits the thermoelectric generators modules to thermal cycling. With the experimental platform proposed the parameters of the thermoelectric generators may be to investigate properly. To evaluate the degradation effects on TEG the parameters were evaluated before the thermal cycling and then the parameters were evaluated after the thermal cycling process. At the research end, the parameters are presented by a comparative table with parameters evaluation before the thermal cycling and parameters evaluation after thermal cycling which brings to the experimental platform reliability.
Objetivo: Os geradores termoelétricos são dispositivos de estado sólido que utilizam a diferença de temperatura para a conversão em energia elétrica. No entanto, submeter os geradores termoelétricos a variações de temperatura pode comprometer o tempo de vida desses dispositivos. Assim, com o objetivo de investigar a possível influência das variações de temperatura ciclos térmicos a que os módulos geradores termoelétricos (TEGs) estão expostos, este trabalho desenvolveu uma plataforma experimental capaz de submeter TEGs à influência de ciclos térmicos, permitindo assim que os TEGs possam ser avaliados. Para constatar os efeitos na degradação do TEG, alguns parâmetros foram avaliados antes da aplicação dos ciclos térmicos e após uma sequência de ciclos térmicos. Ao fim da pesquisa, as avaliações feitas nos parâmetros são apresentadas em uma tabela comparativa, em que são apresentados os valores obtidos antes da aplicação dos ciclos térmicos e os valores dos parâmetros após a aplicação dos ciclos térmicos.

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Maas, Mathieu. « Structuration de générateurs thermoélectriques sur échangeur de type radiateur par électrodéposition ». Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0338/document.

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Face à la raréfaction des énergies fossiles, l’industrie automobile se trouve dans l’obligation de réduire la consommation des véhicules. L’une des idées est de récupérer l’énergie perdue sous forme d’échauffements grâce à la thermoélectricité. L’objectif de ces travaux est l’implantation d’un module thermoélectrique au niveau du radiateur afin d’en récupérer la chaleur dans le cadre d’un projet de recherche financé par Valéo Systèmes Thermiques et l’ADEME. La conception des radiateurs nécessite des épaisseurs supérieures à la centaine de micromètres de matériaux thermoélectriques afin d’en optimiser l’espace disponible. L’électrodéposition est apparue comme la technologie la plus adaptée car elle permet de déposer les matériaux directement sur l’ailette. Cette étude est consacrée aux dépôts électrochimiques de chalcogénures de bismuth (Bi2Te3 et Bi0,5Sb1,5Te3), matériaux les plus performants aux températures de fonctionnement de l’échangeur thermique. La première partie de ces travaux concerne la faisabilité de l’obtention de films d’épaisseurs supérieures à 100 µm et leurs caractérisations : stœchiométrie, structures et propriétés thermoélectriques. L’utilisation originale d’une anode soluble permet l’obtention de films de Bi2Te3 de près de 400 µm. Pour le composé ternaire, la synthèse consiste en une succession de couches de composés différents (Bi0,25Sb0,75-Te0), avant de procéder à leur interdiffusion via un traitement thermique. La dernière partie concerne la réalisation d’un module thermoélectrique. Les multiples étapes de lithographie et de synthèses électrochimiques ont été étudiées afin d’obtenir un module adapté aux échangeurs thermiques. Les caractérisations préliminaires de leurs propriétés montrent des résistances élevées et plusieurs voies d’améliorations sont proposées
In order to face the rarefaction of fossil fuels, the automotive industry has to find new ways to reduce their vehicle consumption. One of the possible ideas is to recover the energy that is lost as heating by using thermoelectricity. The aim of this work is to set-up thermoelectric generators into the radiator in order to recover this lost heat in a frame of research project financially supported by Valéo Systèmes Thermiques and ADEME. The radiator design requires thermoelectric materials thicknesses up to hundred micrometers in order to optimize the available space. Electroplating seems to be the best way to synthesize those materials directly onto the radiator fins. This study focuses on the electroplating of the best thermoelectric materials adapted to the operating temperatures of the heat exchanger: bismuth chalcogenides (Bi2Te3 and Bi0,5Sb1,5Te3). Firstly, a study has been carried out in order to synthesize thick layers above 100 µm of those two materials. Stoichiometry and thermoelectric properties were also determined. The original use of a soluble anode permitted to obtain 400 µm thick Bi2Te3 films. For the ternary compound, the synthesis consisting in a succession of thin layers of Bi0,25Sb0,75 and Te0, before their interdiffusion by annealing, is also presented. Finally, the last part covers the study carried out on the realization of the thermoelectric generators. The multiple stages of lithography and electrochemical syntheses were studied in order to obtain a module adapted to the heat exchanger. The first characterizations evidence high internal resistances and different ways to improve them are also presented

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Ayachi, Sahar [Verfasser], et Boor Johannes [Akademischer Betreuer] de. « Developing contacting solutions for Mg2(Si,Sn)-based thermoelectric generators : evaluating Cu and Ni45Cu55 as candidates for contacting electrodes, and establishing the importance of charged point defects in the contacting process / Sahar Ayachi ; Betreuer : Johannes de Boor ». Duisburg, 2021. http://d-nb.info/1241963169/34.

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El, Oualid Soufiane. « Contribution à la modélisation et à la caractérisation de générateurs thermoélectriques ». Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0104.

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L'internet des objets (Internet of Thing, IoT) suscite de plus en plus d'attention dans l'industrie électronique. L'IoT est un concept selon lequel les objets de tous les jours pourront communiquer ensemble via Internet. La plupart des objets connectés utilisent des batteries qu’il faut changer régulièrement ou recharger. Face à la forte croissance annoncée, la recherche de sources d’alimentation autonomes et alternatives s’appuyant sur des systèmes qui capturent l’énergie ambiante et la convertissent en électricité devient primordiale. Parmi les technologies de récupération d’énergie, la thermoélectricité présente des avantages certains liés à sa simplicité, sa fiabilité et son absence de pièces mobiles et de pollution par émission de gaz à effet de serre. L’ensemble de ces caractéristiques favorables place les convertisseurs thermoélectriques comme des candidats possibles pour fournir aux objets connectés de demain les faibles quantités d’énergie nécessaire à leur fonctionnement ou pour recharger les batteries. Mes travaux de thèse s’inscrivent dans ce contexte et se sont déroulés en partie dans le cadre du projet Européen EnSO (Energy for Smart Objects). Des études numériques menées avec le logiciel commercial Comsol Multiphysics ont été réalisées sur des micro-générateurs planaires innovants développés par la société Mahle, partenaire du projet. L’objectif de ces travaux était de comprendre l’influence de nombreux paramètres (géométrie, conditions aux limites en terme de température ou de flux, propriétés électrique et thermique des matériaux actifs) sur leurs performances thermoélectriques (puissance électrique et rendement). Nous avons montré, en particulier, le rôle critique des résistances de contact électriques et thermiques sur la puissance électrique de sortie. Un second volet, plus expérimental, a été consacré au développement de générateurs thermoélectriques miniatures à forte densité de puissance intégrant des matériaux avancés à base de skutterudites. Plusieurs brasures ont été testées lors de l’assemblage des modules thermoélectriques. La caractérisation des performances des modules (25-500°C) couplée aux calculs numériques ont permis de guider les recherches et d’optimiser les procédés de fabrication. Ce travail a abouti à l’obtention d’une densité de puissance record (3,3 W/cm2 pour une différence de température de 450 K) par rapport à l’état de l’art
The Internet of Thing (IoT) is currently being intensively explored in the electronic industry. IoT is an extension of Internet connectivity into physical end everyday-life objects which will be able to communicate and interact with each other’s. Most of these connected objects are powered by batteries that need to be regularly switched or recharged. Faced with a strong announced growth of their number in coming years, the search for novel alternative, autonomous power supplies that convert surrounding available energy into electricity becomes essential. Among energy harvesting technologies, thermoelectricity is advantageous due to its simplicity, reliability, the absence of moving parts and greenhouse gas emissions. All these favorable characteristics make thermoelectric converters possible candidates for powering or recharging batteries of connected objects. In this context, my PhD work was done within the frame of the European project EnSO («Energy for Smart Objects»). Numerical studies with the software Comsol Multiphysics were performed on innovative planar micro-generators developed by the Mahle company, one of the partners of this project. The main objective of this work was to achieve a better understanding of the influence of numerous parameters (geometry, boundary conditions in terms of temperature and flux, electrical and thermal properties of the active materials) on their thermoelectric performances (output power and efficiency). In particular, we have underlined the critical role played by the electrical and thermal contact resistances on the output power. A second part of this study has been devoted to the experimental development of miniaturized thermoelectric generators capable of delivering high output power density through the integration of skutterudite materials. Several brazes have been tested during the assembly operations of the thermoelectric modules. The characterization of the module performances (25-500°C) combined with numerical calculations have been used as a guidance for optimizing the fabrication process. This work culminated in the successful fabrication of a thermoelectric module with a record-breaking power density of 3,3 W/cm2 achieved under a temperature difference of 450 K

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Доброжан, Олександр Анатолійович, Александр Анатольевич Доброжан, Oleksandr Anatoliiovych Dobrozhan, Анна Олександрівна Салогуб, Анна Александровна Салогуб, Anna Oleksandrivna Salohub, Ярослав Володимирович Знаменщиков et al. « 3D printing of nanoinks based on the metal and semiconductor nanoparticles ». Thesis, Sumy State University, 2017. http://essuir.sumdu.edu.ua/handle/123456789/66532.

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Nowadays, we observe the transition for creation of the domestic and industry objects from the traditional methods involving the assembling of the different parts obtained by cutting, molding or otherwise to the additive manufacturing which refers to the object formation by using a layer-by-layer deposition of the versatile materials (metals, plastics, glasses, and so on) in the one 3D printing technological process. In the electronics, the attention should be given to the especially perspective technology, that is 3D ink printing of inks based on the metal nanoparticles (Ag, Cu, Sn) to obtain the printed circuit boards, charge-collecting contacts of thin-film solar cells and its connections with the external loads. Moreover, the inks based on the semiconductor materials (Cu2ZnSn(S,Se)4, ZnO) are the promising for the use in the sensitive elements of photoconverters, thermoelectric generators, transparent electronics, gas sensors, and touchpads.

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Abi, Sejaan Georgina. « Energy harvesting and storage in multi-stable micro-actuator systems ». Electronic Thesis or Diss., Compiègne, 2022. http://www.theses.fr/2022COMP2698.

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Le principe de récupération d'énergie est appliqué dans cette thèse à un système de micro-actionneur bistable sans fil, développé au laboratoire de Roberval. Le micro-actionneur bistable est composé de deux poutres antagoniste bistable, de deux éléments en alliage à mémoire de forme (SMA) et d'une source laser. Le faisceau laser est utilisé comme source de transfert d'énergie sans contact pour actionner les éléments SMA. A leur tour, les éléments SMA sont les composants de transition pour activer les faisceaux bistables entre ses deux positions stables. Dans ce contexte, l'objectif de cette thèse est de récolter différents types d'énergies disponibles inutilisées dans ce système. Pour commencer, l'énergie optique est récupérée en utilisant l'effet photovoltaïque transformant l'énergie optique en énergie électrique. De plus, du fait de l'échauffement ambiant, la différence de température est captée par effet thermoélectrique transformant cette différence de température en une différence de tension. L'objectif global est de créer deux différents systèmes pour la récupération d'énergie dans le système. Le premier système repose sur la récupération de l'énergie optique uniquement. Cette conception sera utilisée lorsque le micro-actionneur nécessite une énergie électrique supplémentaire sans nécessiter une grande vitesse d'actionnement. Cependant, lorsque la vitesse représente une priorité par rapport à l'énergie électrique demandée, le micro-actionneur bascule pour fonctionner dans le deuxième système de récupération d’énergie où les énergies optiques et thermiques sont récupérées alors que la vitesse d'actionnement du micro-actionneur est supérieure à la première conception
The principle of energy harvesting is applied in this thesis to a wireless bistable micro-actuator system, developed in the Roberval laboratory. The bistable micro-actuator is made up of an antagonistic pre-shaped double beams, two shape memory alloy (SMA) elements and a laser source. The laser beam is used as a contactless energy transfer source to actuate the SMA elements. At their turn, SMA elements are the transitional components to activate the bistable beams among its two stable positions. From this context, the aim of this thesis is to harvest different types of unused available energies in this system. To start with, optical energy is harvested using the photovoltaic effect transforming optical energy into electrical energy. Moreover, due to the environment heating, the difference in temperature is harvested using thermoelectric effect transforming this difference in temperature into a voltage difference. The overall objective is to create two different playgrounds of energy harvesting in the system. The first one relies on harvesting only the optical energy. This design will be used when the micro-actuator requires an additional electrical energy without requiring high speed of actuation. However, when the speed represents a priority comparing to the electrical energy in demand, the micro-actuator switches to operate in the second playground where optical and thermal energies are harvested while the speed of actuation of the micro-actuator is higher than the first design

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Lin, Jia-Zhag, et 林嘉哲. « Fabrication of PDMS Flexible Thermoelectric Generators ». Thesis, 2015. http://ndltd.ncl.edu.tw/handle/75051200841153710668.

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碩士
國立中興大學
機械工程學系所
103
This study develops the fabrication of PDMS (Polydimethylsiloxane) flexible thermoelectric generators. The thermoelectric structure is composed of 24 pairs thermocouple that is made of P-type thermoelectric material 〖"Bi" 〗_"2" 〖"Te" 〗_"3" and N-type thermoelectric material 〖"Sb" 〗_"2" 〖"Te" 〗_"3" . Each thermocouple is 4 mm wide, 1.5 mm long and 2 mm high, the space between thermocouples is 0.7 mm, and the surface area is 50×50 〖"cm" 〗^"2" . The flexible thermoelectric generators is designed by Solidworks and AutoCAD, and then assembled by turning over the mold. In order to achieve more flexible, perfused PDMS is used to manufacture the supporting base and package the thermoelectric generators. When the hot part temperature is 373 k and cold part temperature 293 k, the practical effect of the thermoelectric generators temperature difference between internal 55 K. The experimental results show The generators have an output voltage 3.37 V and a output power of 25.81 "μW" at temperature difference of 55 K. The voltage factor of the thermoelectric generators is 2.45 mV/" c" "m" ^"2" K, and the power factor is "1.38×" 〖"10" 〗^"-2" "μW/" 〖"cm" 〗^"2" "K" ^"2" .

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Sevilla, Galo T. « Flexible Thermoelectric Generators on Silicon Fabric ». Thesis, 2012. http://hdl.handle.net/10754/253713.

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In this work, the development of a Thermoelectric Generator on Flexible Silicon Fabric is explored to extend silicon electronics for flexible platforms. Low cost, easily deployable plastic based flexible electronics are of great interest for smart textile, wearable electronics and many other exciting applications. However, low thermal budget processing and fundamentally limited electron mobility hinders its potential to be competitive with well established and highly developed silicon technology. The use of silicon in flexible electronics involve expensive and abrasive materials and processes. In this work, high performance flexible thermoelectric energy harvesters are demonstrated from low cost bulk silicon (100) wafers. The fabrication of the micro- harvesters was done using existing silicon processes on silicon (100) and then peeled them off from the original substrate leaving it for reuse. Peeled off silicon has 3.6% thickness of bulk silicon reducing the thermal loss significantly and generating nearly 30% more output power than unpeeled harvesters. The demonstrated generic batch processing shows a pragmatic way of peeling off a whole silicon circuitry after conventional fabrication on bulk silicon wafers for extremely deformable high performance integrated electronics. In summary, by using a novel, low cost process, this work has successfully integrated existing and highly developed fabrication techniques to introduce a flexible energy harvester for sustainable applications.

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Chen, Yu-Wei, et 陳佑維. « Fabrication of Thermoelectric Micro Generators with Carbon Nanocapsules ». Thesis, 2017. http://ndltd.ncl.edu.tw/handle/69785822575083200401.

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碩士
國立中興大學
機械工程學系所
105
In this study, we present a thermoelectric microgenerator fabricated using the standard 0.18 μm CMOS (complementary metal oxide semiconductor) process are investigated. The thermoelectric microgenerator consists of 129 thermocouples in series, and the thermocouples are composed of p-type and n-type polysilicons. The output power of microgenerator relies on the temperature difference between the hot and cold parts of thermocouples. To increase the temperature difference of thermocouples, the hot part of thermocouples is designed as the suspended structure. Then, the hot part of the thermocouples is coated by CNCs (Carbon nanocapsules) that increasing absorb radiant heat source. The cold part of thermocouples is formed on the silicon substrate, and covered by silicon oxide that provides low thermal conductivity and thermal isolation. The FEM (finite element method) software of ANSYS Workbench is employed to simulate the temperature distribution and temperature difference of the thermoelectric microgenerator, and analyzed the optimal geometry of the thermocouples. The experimental results showed that the output voltage and output power of the microgenerator without CNCs film were 4.426 mV, and 224.65 pW, respectively, at the temperature difference of 3.6 K. The output voltage and output power of the microgenerator with CNCs film were 5.845 mV and 391.789 pW, respectively, at the temperature difference of 4.3 K. The microgenerator had the voltage factor of 0.882 mV/k/mm2 and the power factor of 13.686 pW/K2/mm2.

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Cheng, Huei-Min, et 鄭慧敏. « Performance of Metal Foam applied in Thermoelectric generators ». Thesis, 2013. http://ndltd.ncl.edu.tw/handle/81197303575568956663.

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碩士
國立交通大學
機械工程系所
101
Thermoelectric generation has received higher attentions in recent year. This research aims to improve the Thermoelectric generation efficiency by changing operating conditions and hot side heat exchanger, including copper plate, metal foam, blackbody plate and carbon foam. The results present by high heater temperature, high ambient temperature and approaching the heater will get larger heat transfer rate. And it leads to higher efficiency. Fixed 10PPI change porosity, even though it get more heat transfer rate because of high surface area, it also caused temperature gradient. At the same high 5mm, 50PPI metal foam enhance natural convection heat transfer rate by larger surface area. But larger surface area also leads to lower hot side temperature. The efficiency decrease 24.2~35.9%. Besides, higher emissivity and carbon foam enhances more radiative heat transfer and lead to higher efficiency. After painting blackbody, the plane efficiency raise 1.16~3 times, 10PPI metal foam enhance 2.4~5.6 time. And carbon foam at heater temperature 350℃ and 10mm away from heater get the highest efficiency.

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Rosmaninho, Miguel Mota Prego. « Electrodeposition of Bi 2 Te3 Nanomaterials for Thermoelectric generators ». Master's thesis, 2014. https://repositorio-aberto.up.pt/handle/10216/78197.

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Rosmaninho, Miguel Mota Prego. « Electrodeposition of Bi 2 Te3 Nanomaterials for Thermoelectric generators ». Dissertação, 2014. https://repositorio-aberto.up.pt/handle/10216/78197.

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Yeh, Chun-Chia, et 葉峻嘉. « Fabrication and Characterization of Thermoelectric Micro Generators with Carbon Nanotube ». Thesis, 2013. http://ndltd.ncl.edu.tw/handle/68260636366833524023.

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碩士
國立中興大學
機械工程學系所
101
This study presents a micro thermoelectric power generator fabricated by the standard 0.18 μm 1P6M (one polysilicon and six metals) CMOS (complementary metal oxide semiconductor) process. The micro thermoelectric power generator is composed of 370 thermocouples in series, and the thermocouples are formed by p-type and n-type polysilicon. The efficiency of the micro generator depends on the temperature difference between hot and cold parts of thermocouples. In order to achieve the best generation efficiency, the reactive ion etching (RIE) is used to release the hot part of thermocouples. Then, the hot part of the thermocouples is coated by MCNTs (Multi-walled carbon nanotubes). The cold part of the thermocouples is covered by silicon oxide that provides low thermal conductivity and thermal isolation. ANSYS Workbench is used to simulate the temperature distribution and the temperature gradient of the micro generator. The experimental results showed that the output voltage of thermoelectric generator without MCNTs film was 0.899 mV and the output power was 1.72 pW when temperature was 400 K. The output voltage and output power of the generator with MCNTs film were 1.56 mV and 5.16 pW, respectively, at the temperature of 400 K. The micro generator with the MCNTs film had a voltage factor of 0.225 mV/K/mm2 and a power factor of 0.745 pW/K2/mm2. Finally, the charging circuit is designed to carry out the storage of output power, and the power can be apply in the low power electronic component.

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Thèses sur le sujet « Thermoelectric, Cu2SnS3, thermoelectric generators »

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