Optimal working conditions for thermoelectric generators with realistic thermal coupling (original) (raw)

Thermoelectric generator (TEG) technologies and applications

2021

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...

Review on Design and Analytical Model of Thermoelectric Generator

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.

Effective thermal conductance of thermoelectric generator modules

Renewable Energy and Power Quality Journal, 2017

Recent studies have analyzed the viability of generating electricity by means of thermoelectric modules applied to processes with large amounts of waste heat. The simulation of the performance of large-scale designs of thermoelectric generators (TEGs), however, is a very complex task since it involves a coupling between both electrical and thermal phenomena. In addition, a single TEG module contains tenths of small P-type and N-type semiconductor legs, which implies that the simulation must take into account domains with characteristic lengths that vary several orders of magnitude. Here, we propose a methodology for determining the effective heat conductance of a single TEG module that can be employed for simulating the entire element without entry into the details of its inner composition. The effective thermal conductance here proposed can be understood as the coefficient that predicts, at different operating conditions, an upper bound of the electrical power generated by the TEG module.

Physical Generation in Thermoelectric Generators

International Journal of Advance Research and Innovative Ideas in Education, 2021

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. Furthermore, Thermoelectric generators have been found as a viable solution for direct generation of electricity from waste heat in industrial processes. This paper presents in-depth analysis of TEGs, beginning with a comprehensive overview of their working principles such as the Seebeck effect, the Peltier effect, the Thomson effect and Joule heating with their applications, materials used, Figure of Merit, improvement techniques including different thermoelectric material arrangements and technologies used and substrate types.

Dynamic Performance Characteristics of a Thermoelectric Generator

Journal of Thermal Engineering, 2019

A thermoelectric generator (TEG) is a device that transforms thermal energy directly into electrical power by exploiting the Seebeck effect. In the current study, the dynamic performance characteristics of a TEG is experimentally studied under different operating conditions. The Influence of input heat rate and the influence of utilizing extended surfaces (fins) on both transient and steady-state performance of a TEG are experimentally investigated. The variation in the temperatures of the TEG hot-and cold-side in addition to the output voltage is taken as a denotation of the performance characteristics. Input heating rate of 15.0 W, 17.5 W, 20.0 W, 22.0W and 25.0 W are applied to the TEG hot-side. Free air convection (FC) is utilized for heat dissipation from the TEG module through the cold-side. From the experimentation, it can be concluded that increasing the input heating rate provides a higher temperature difference between the module sides leading to higher power output. Addit...

An Experimental Investigation into Improving the Performance of Thermoelectric Generators

Journal of Ecological Engineering, 2022

Low-temperature heat sources have become increasingly popular in recent years, particularly for energy generation. The majority of thermal devices in the market (including devices using solar energy, geothermal energy, waste energy, and so on) transform heat into electricity indirectly, requiring mechanical work before producing power. Through the Seebeck effect, the technology that employs a thermoelectric generator (TEG) may directly transform heat energy into electricity. The TEG technology provides several advantages, including compactness, quietness, and the absence of moving components. TEGs have a low thermal and electrical efficiency, which is one of their main drawbacks. Therefore, the performance of a thermoelectric generator is improved by employing liquid evaporation heat transfer in this manuscript. The performance of the thermoelectric was examined experimentally and compared to the liquid evaporation mode under varied heat flux values and different modes of heat transfer in terms of free and forced convection with and without fins. The experimental results revealed that when compared to free convection without fins, adopting forced liquid evaporation convection would improve TEG voltage variation by 435.9%.

Influence of thermal environment on optimal working conditions of thermoelectric generators

Journal of Applied Physics, 2014

Optimization analyses of thermoelectric generators operation is of importance both for practical applications and theoretical considerations. Depending on the desired goal, two different strategies are possible to achieve high performance: through optimization one may seek either power output maximization or conversion efficiency maximization. Recent literature reveals the persistent flawed notion that these two optimal working conditions may be achieved simultaneously. In this article, we lift all source of confusion by correctly posing the problem and solving it. We assume and discuss two possibilities for the environment of the generator to govern its operation: constant incoming heat flux, and constant temperature difference between the heat reservoirs. We demonstrate that, while power and efficiency are maximized simultaneously if the first assumption is considered, this is not possible with the second assumption. This latter corresponds to the seminal analyses of Ioffe who put forth and stressed the importance of the thermoelectric figure of merit ZT. We also provide a simple procedure to determine the different optimal design parameters of a thermoelectric generator connected to heat reservoirs through thermal contacts with a finite and fixed thermal conductance.

Optimization of thermoelectric generator operation with dissipative coupling to heat baths

** Slides of a talk that I gave at the ICT 2013 in Kobe, Japan. It contains an updated list of the main publications. ** When a thermoelectric generator (TEG) is coupled to two heat baths with non-ideal heat exchangers, its performance crucially depends on the working conditions. From a thermodynamic viewpoint a TEG is a heat engine operating in a steady-state mode using the thermoelectric material’s conduction electrons as a working fluid. An analysis of performance optimization thus must focuse on the interplay between the constitutive laws of the device and those which govern its interaction with the environment. We start by giving an analytical form for the current-dependent thermal conductance of the TEG, which characterizes the coupling between the input and output of the device. This reflects the global displacement of the charge carriers in the system, which we associate to a convection process in opposition to conduction related to both phonon transport and heat transport b...