Characteristics Of Thermoelectric Generator Research Articles

Potential applications of thermoelectric generators (TEGs) in various waste heat recovery systems

Nowadays the World faces critical issues, such as increasing power costs, environmental impacts of fossil fuel, and global warming. In this respect, scientists are trying to improve the efficiency of the energy harvesting. The enhancement of power generation sectors is focused on the waste heat recovery systems based on thermoelectric generators (TEGs) that have demonstrated the capacity to transfer thermal energy directly into electric energy via the Seebeck effect. TEG uses the available waste heat sources in different applications to produce power, thus it considered as an eco-friendly power source. In the present study, the integration of thermoelectric systems with other technologies for green power production is introduced. This work introduces a background about the common materials used in the fabrication of the TEG. Furthermore, the application of the TEG to harvest waste heat from different sources, i.e., fuel cells, heat exchangers, photovoltaics, internal combustion engine, electric vehicles, and hybrid waste heat recovery systems have been summarized. The characteristics of thermoelectric generators are discussed, considering the different operating and design parameters. Finally, the barriers and challenges facing the applications of the thermoelectric generators for waste heat recovery are also discussed.

Research on characteristics of thermoelectric generator with integrated muffler and catalytic converter

Automobile exhaust contains a large amount of heat loss, which has a high potential for energy saving. In order to recover the heat in the exhaust gas and improve the compatibility of thermoelectric generator (TEG), muffler and catalytic converter, an integrated automobile exhaust thermoelectric generator (IATEG) integrating muffler, and catalytic converter is proposed. Research on its performance by establishing a three-dimensional model, On the basis of finite element simulation, the model’s surface temperature field, muffler transmission loss, exhaust back pressure and conversion efficiency are compared and studied when the catalytic converter is placed in the front part (A), middle part (B) and rear part (C) of the model. The results show that when the exhaust temperature is 350 °C and the inlet velocity is 30 m/s, the average surface temperature of model B is the highest, which is 291.95 °C. The exhaust back pressure of the three models is almost the same and meets the requirements of QC/T 631-2009 (15 kPa). Compared with the original muffler of the automobile, the transmission loss of the three models is greater than that of the original muffler. From the perspective of improving the conversion efficiency of NOx, the exhaust flow field distribution of the catalytic converter of Model B is more uniform and has a smaller impact on the conversion efficiency of NOx. Therefore, it is recommended that IATEG choose the structure of Model B. This article demonstrates the possibility of IATEG integrating muffler and catalytic converter in terms of performance.

Promising Development of Thin Film and Flexible Thermoelectric Devices

The temperature dependences of the thermoelectric properties of Ge2Sb2Te5 (p-type) and Bi2Te2.8Se0.2 (n-type) thin films obtained by magnetron and vacuum thermal evaporation, respectively, are under investigation. The effect of crystallization on the Seebeck coefficient of Ge2Sb2Te5 thin films is established. The temperature dependences of the power factors of the investigated thin films are determined. Film thermoelements based on Ge2Sb2Te5 and Bi2Te2.8Se0.2 materials have sufficiently high thermoelectric properties and can be used for manufacturing flexible film thermoelectric generators (TEGs). Computer simulation of the characteristics of a flexible film TEG using the proposed multi-physics model of a flexible film TEG is carried out. The characteristics of the TEG are determined at various ambient temperatures and various electrical loads, which make it possible to optimize the geometric parameters of thermoelements. The optimal operating temperatures of TEGs for wearable electronics are determined.

Study into the Influence of Internal Heat Sources on the Operating Characteristics of a Thermoelectric Generator

The influence of internal heat sources on temperature distribution during the operation of thermoelectric generators (TEG) is investigated. Taking into account various factors affecting the temperature regime, including internal heat sources, a multilevel model of a two-stream TEG has been developed, which allows one to calculate the temperature distribution and the integral characteristics of the generator. The calculations were carried out using the PHOENICS program package; as a result, the dependences of the electrical characteristics and the temperature drop on the junctions on the load resistance, speed, and coolant temperature were obtained. A comparison is made with the corresponding indicators in the absence of internal heat sources. It is concluded that the influence of internal heat sources on the temperature drop and electric power increases with decreasing load resistance. Thus, in the maximum power mode, which corresponds to the ratio of the load resistance to the internal resistance of the module m = 1.15, the temperature drop decreases by 3.5–4.0%, while that at m = 0.01 is by 7.5–8.5%. TEG power in maximum power mode decreases by 7.5–8.0%. Studies have shown that the influence of internal heat sources on the characteristics of the TEG is more substantial when the flow rate in the heat exchangers is lower. The greatest decrease in the values of indicators due to the influence of internal sources was observed at v = 0.2 m/s and amounted in maximum power mode to 5.5–6.0% for the temperature difference and 12–13% for power. The results obtained indicate that the influence of internal sources on the characteristics of TEGs is significant enough, which implies that the most accurate estimates of the thermal and electrical performance of TEGs can be made only by taking into account the effect of internal heat sources on the temperature distribution in TEGs.

Acquisition and Monitoring System for TEG Characterization

This paper presents an acquisition system for measuring and characterization of thermoelectric generators (TEGs) for energy harvesting purposes on wireless sensors networks (WSNs). This system can monitor and characterize up to three TEGs simultaneously and is comprised of two main electronic circuits: the first one is composed of 12 input channels being three for reading voltage, three for reading current by making use of instrumentation amplifiers (ACS712), and six thermocouples for signal reading (<400°C). The second electronic circuit consists of a proportional-integral-derivative (PID) controller with two pulse width modulation (PWM) input channels for controlling the heat (thermoresistance) and cooling (controlled cooler) sources, respectively, following a predefined temperature gradient. The TEG measured data for the voltage, current, and temperature can be acquired in real-time with an application written on Delphi language and displayed both through a numeric and graphical display. In order to validate the precision and accuracy two commercial TEG modules (inbC1-127.08HTS) compatible with temperatures up to 200°C without signal degradation were used in series. The functional prototype of the implemented system had a cost under ≈430 USD, making it suitable where a good knowledge of the electrical characteristics of TEGs is of major interest, especially on cogeneration systems.