Effective thermal conductance of thermoelectric generator modules (original) (raw)
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Energy Procedia, 2015
Transient multiphysics simulations are performed to investigate the thermal and electric performance of a thermoelectric generator (TEG) module placed between hot and cold blocks. Effects of heat radiation, thermal and electric contact on the TEG are examined and the simulated results are compared with experimental data. The predicted temperature difference across the TEG module and the electric voltage and power are in very good agreement with the experimental data. The radiation effect on the thermal and electric performance is negligible and the temperature at the interface of the TEG module substrates is predicted to be non-uniform. The peak temperatures are found in the both ends of the legs, and the maximum Joule heat is generated at the leg ends connected with the hot substrate.
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International Journal of Scientific Research, 2012
Despite all advances in the miniaturization of Microsystems which depend on a central power source or bulky batteries with limited lifetime. Growing fields like autonomous Microsystems or wearable electronics urgently look for micro scale power generators. One possible solution is to convert waste heat into electrical power with TEG. Thermoelectric generator is a useful and environment friendly device with the advent of semiconductor materials the efficiency of a TEG can even be an alternative for the conventional heat engines. To fabricate thermoelectric generators, one must design the structure of the TEG. This study investigated the role of the dimensions of TEG, including the length, and cross-sectional area of the thermo elements to evaluate the power and efficiency, The governing equations were derived from the Seebeck effect and Peltier effect. We calculated the thermoelectric power generated by the TEG and efficiency. The thermoelectric simulation produced design guidelines for high-performance TEG.
Applied Thermal Engineering, 2019
Design and development of a thermoelectric module and in its use in real application require an accurate simulation tool, which provides electrical and thermal characterizations as a function of temperature. The problem of correctly solving the basic thermoelectric equations originates from the fact that junctions temperatures are unknown and normally cannot be measured, whereas only external temperatures are available in testing and real applications. Due to thermal losses in passive layers, the internal temperatures can be significantly different. At the same time all the equations contains temperature dependent parameters. Many approximations are usually introduced to achieve results. Here we propose a simple iterative method to obtain the temperature losses and calculate all thermoelectric performances with corrected temperatures. The method, developed in Matlab language, takes into account temperature dependent material properties, thermal and electrical resistance of passive elements (electrodes, ceramics, interfaces, contact pad, etc.). Joule heating, Peltier and Thomson effects are considered in determine the temperatures. The effectiveness of the proposed procedure and the differences between approximated methods are investigated. The accuracy is proved with two commercial modules: the deviation were found to be within 4% and 3%. The code demonstrates to converge in few iterations in both cases. Moreover, the robustness has been investigated as a function of different parameters confirming that the code is suitable also for parametric simulations.
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Nowadays humans are facing difficult issues, such as increasing power costs, environmental pollution and global warming. In order to reduce their consequences, scientists are concentrating on improving power generators focused on energy harvesting. Thermoelectric generators (TEGs) have demonstrated their capacity to transform thermal energy directly into electric power through the Seebeck effect. Due to the unique advantages they present, thermoelectric systems have emerged during the last decade as a promising alternative among other technologies for green power production. In this regard, thermoelectric device output prediction is important both for determining the future use of this new technology and for specifying the key design parameters of thermoelectric generators and systems. Moreover, TEGs are environmentally safe, work quietly as they do not include mechanical mechanisms or rotating elements and can be manufactured on a broad variety of substrates such as silicon, polyme...
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The efficiency at which thermoelectric generators (TEGs) can convert heat into electrical energy is governed by the properties of the employed functional materials. For a given thermoelectric (TE) material, efficiency needs to be maximized by adjusting, e.g., the carrier concentration n. Usually, chemically homogeneous materials with a constant n along the leg are employed to fabricate TEG. However, for most TE materials, the optimum n has a pronounced temperature dependence, typically increasing toward the hot side of the leg. A local variation of n, either continuously (grading) or discontinuously (segmenting), thus has the potential to increase the efficiency of TEGs substantially. Predictions on efficiency gain are challenging, and an adequate physical model for the thermoelectric transport properties in the material as well as the device is required here. To address this challenge, we have combined a two-band model to describe the material properties with a device model based o...
Case Studies in Thermal Engineering, 2017
Transient and steady-state multiphysics numerical simulations are performed to investigate the thermal and electrical performances of a thermoelectric generator (TEG) module placed between hot and cold blocks. Effects of heat radiation, leg length and Seebeck coefficient on the TEG thermal and electrical performances are identified. A new correlation for the Seebeck coefficient with temperature is proposed. Radiation effects on the thermal and electric performances are found to be negligible under both transient and steady-state conditions. The leg length of the TEG module shows a considerable influence on the electrical performance but little on the thermal performance under transient conditions. A nearly linear temperature profile on a leg of the TEG module is identified. The temperature profile of the substrate surfaces is non-uniform, especially in the contacted areas between the straps (tabs) and the substrates.
Characterization of thermal interface resistance in thermoelectric generators
MRS Proceedings, 2011
Thermoelectric generators are actively being pursued to recover waste heat from the auto exhaust gas to improve vehicle fuel economy. Efficiency of a thermoelectric generator is defined as the ratio of electrical power output to the heat input. In a typical thermoelectric generator, a heat exchanger captures the heat from the medium (ex: hot exhaust gas heat) and this heat needs to be transferred to the hot end of the thermoelectric elements with minimum losses. It is important to understand and minimize these thermal losses to improve the efficiency of a thermoelectric generator. Accurate measurement of the thermal interface resistance parameters is also important because they are used in a comprehensive thermoelectric system model to predict the performance of the generator under actual use conditions. To understand the factors influencing the thermal interface resistance, and to determine the effective thermal interface resistance between the heat exchanger and the thermoelectric hot shunts in a prototype generator that is currently being developed for auto exhaust heat recovery application, we have designed and built a test setup to characterize the thermal interface resistance under high heat flux conditions. Measured temperature profiles in the test sample, heat input into the test device and its geometry are fed into a thermal model to extract the thermal conductance parameters. Factors affecting the thermal interface resistance and the influence of different interface materials were evaluated. Suitable solutions with minimum thermal loss were selected for building the prototype thermoelectric generator for waste heat recovery application and validating the system model.