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Thermal energy harvesting from asphalt pavement roadways
Published in Andreas Loizos, Imad L. Al-Qadi, A. (Tom) Scarpas, Bearing Capacity of Roads, Railways and Airfields, 2017
Utpal Datta, Samer Dessouky, A.T. Papagiannakis
The TEGs generate power in response to temperature gradients, which is referred to as the See beck effect (Thermoelectric generator). There are four engineering parameters which define the performance of a TEG: ΔT: Temperature gradient (difference), between the hot and cold side of the TEG;V: Voltage generated by TEG due to temperature gradient;IL: Electric current drawn by the TEG andPL: Output power produced by the TEG.
The Prospect of Energy-Harvesting Technologies for Healthcare Wireless Sensor Networks
Published in Daniel Tze Huei Lai, Rezaul Begg, Marimuthu Palaniswami, Healthcare Sensor Networks, 2016
Thermal energy is another example of an alternative energy source. Several approaches to convert thermal energy into electricity are currently under investigation (through the Seebeck effect, thermocouples, or a piezothermal effect; Hudak and Amatucci 2008). The efficiency of these approaches is related to Carnot’s law, expressed by the equation η = (Tmax − Tmin)/Tmax. According to Carnot’s equation, for a thermal gradient of 5 K with respect to the normal ambient temperature of 300 K, the thermal EH (TEH) efficiency is computed to be around 1.67%. Consider a silicon device with a thermal conductivity of 140 W/mK, as illustrated by Cottone (2008). The heat power that flows through conduction along a 1 cm length for ΔT = 5 K is 7 W/cm2. Hence, the electrical power obtained at Carnot’s efficiency is calculated to be 117 mW/cm2. At first sight, this heat power density of 7 W/cm2 seems to exhibit an excellent result, but the TEH devices have efficiencies well below the simple Carnot’s rule, so the attainable electrical power density turns out to be a small fraction of that, which is only 117 mW/cm2. Many studies on TEH devices have been discussed in the literature, and the thermoelectric generator (TEG) is one of the popular devices that have been developed to harvest thermal energy based on Seebeck effect. A summary of the implemented TEGs, capable of generating from 1 to 60 μW/cm2 at a 5 K temperature differential, is given in a review paper by Hudak and Amatucci (2008).
Hybrid Energy Harvesting System
Published in Yen Kheng Tan, Energy Harvesting Autonomous Sensor Systems, 2017
In the TEH subsystem, a miniaturized thermoelectric generator (TEG) housed in the thermal energy harvester is used for converting thermal energy into electrical energy. The thermal energy, generated from the heat source at a certain high temperature of TH, is channelled through the enclosed TEG via a thin film of thermally and electrically conductive silver grease between them to the heat sink. The residual heat accumulated in the heat sink is then released to the surrounding ambient air at a lower temperature TC. An equivalent thermal circuit model of the thermal energy harvester that illustrates its thermal and electrical characteristics is provided in Figure 5.19.
Applying student psychology-based optimization algorithm to optimize the performance of a thermoelectric generator
Published in International Journal of Green Energy, 2023
Xi Wang, Paul Henshaw, David S-K Ting
Fossil fuel has been used as the main energy source over the past century and a half. During this period, emissions of CO2 produced from fossil fuel combustion led to a rise in the global average temperature, which could reach more than 2 degrees compared to that of the preindustrial era (Ojelade and Zaman 2021). It is widely acknowledged that global warming is one of the main threats to humans. Currently, many governments in the world have increased their investment in exploiting clean energy technology to achieve true carbon neutrality in 2050 (International Energy Agency 2020). The thermoelectric generator (TEG) is a semiconductor-based device that converts a temperature difference into electricity It is considered one of the potential clean technologies, due to its zero emissions while working (Bhuvanesh et al. 2018). The breakthroughs in semiconductor materials have led to remarkable development in TEG technology over the past decades, and the power generation from the multi-TEGs within a modular connection can reach 5 kW (Mamur et al. 2021). However, there are some shortcomings among the commercialized TEG modules, such as low power output and conversion efficiency (Mamur et al. 2021). Compared to photovoltaic or wind power technology, TEGs have not been considered as a developed technology. In this way, an increasing number of researchers have undertaken studies to improve and optimize the TEG performance further.
Investigating the influence of Thomson effect on the performance of a thermoelectric generator in a waste heat recovery system
Published in International Journal of Green Energy, 2019
Mohammad Kalteh, Hossein Akhlaghi Garmejani
A thermoelectric generator (TEG) converts heat to electrical power directly by the means of Seebeck effect; that is when a temperature difference exists between two dissimilar metals or semiconductors, an electromotive force will be appeared (Row 2005). Using a thermoelectric generator is one of the clean methods to recover the waste heat in the cases such as automobile exhaust heat (Decher 1997). Seebeck, Thomson, and Peltier phenomena make the base of thermoelectric science named thermoelectric effects. Thomson effect is the heat absorption or evolution in the presence of temperature difference and electrical current along a metal or semiconductor (Row 2005). The amount of Thomson heat generated or absorbed in a thermocouple is directly proportional to the derivative of the Seebeck coefficient as a function of temperature. Since, the temperature of the semiconductors used in a TEG has noticeable changes along its height, the Thomson effect along the current direction can have important influence on the TEG performance. Obviously, the amount of its influence depends on the type of the material and its temperature-dependence Seebeck relation. So far, different modeling and simplifying studies based on analytical or numerical methods have been carried out to access the best performance of TEGs in different conditions. Generally, all of the researches in this field can be divided into two branches: researches on the enhancement of the TEG’s material according to the thermoelectric properties, and the next is the studies on the geometrical structure to gain the optimum condition.