Road to advanced thermoelectric generators

Significance 

Presently, rigorous climate change and global warming have compelled policymakers and relevant stakeholders to come up with rules and regulations to promote environment conservation and energy saving. For instance, the development of other electricity generating methods is highly desirable to reduce the overdependence on fossils fuels, which is among the leading environmental pollutants. The current advancement in thermoelectric technologies has led to the direct conversion of heat into electricity. This has approved useful in numerous application such as automobile and geothermal industries.

Generally, the conversion of heat into electricity in the thermoelectric materials is based on the Seebeck effects. However, the difficulty in accurately determining the thermoelectric parameters have remained a challenge thus hindering proper quantification of the thermoelectric modules’ performance as well as the development of more efficient fabrication methods. As such, several techniques such as steady-state method have been developed to evaluate different properties of the thermoelectric modules. However, regardless of the remarkable achievements, characterization of the temperature-dependent parameters have not been fully explored.

To this note, a group of Xi’an Jiaotong University researchers Dr. Hailong He, Ms. Weiwei Liu, Professor Yi Wu, Professor Mingzhe Rong, Mr. Peng Zhao, and professor Xiaojun Tang from the State Key Lab of Electrical Insulation and Power Equipment proposed a new method for characterization of temperature-dependent thermoelectric parameters. The main focus was to improve on efficiency and accuracy so as to develop high-performance thermoelectric devices for electricity generation. Fundamentally, the proposed method was based on the quasi-steady state method implemented using both short circuit and open circuit tests. Their work is currently published in the research journal, Energy Conservation, and Management.

Briefly, the authors commenced their experimental work by exploring all the thermoelectric and irreversible effects such as Seebeck and Peltier effects which are relevant for modeling thermoelectric couples. Next, a three-dimensional model was designed using COMSOL software to enable simulation and test analysis for validating the effectiveness of the proposed method. Consequently, the authors validated the time-saving concept by comparing the modeling of both single and compete thermoelectric modules. Eventually, the overall efficiency and effectiveness of the new model were verified by comparing the test and simulations results.

The authors observed that both the simulated and experimental results exhibited good agreement thus validating the effectiveness and feasibility of the newly proposed numerical model. For instance, the overestimated heat flow was recorded as 12.6% due to the measurement uncertainties while a corresponding similarity for the electrical output and NRMSE was recorded as slightly less than 2%.

In summary, the research team successfully developed an efficient method for characterizing temperature-dependent parameters for thermoelectric modules. To actualize their study, they introduced the quasi-steady state method to enhance the accuracy and time saving in calculating thermoelectric parameters. Both good correlations were observed for the calculated thermoelectric parameters through simulation and those provided by the manufacturer. Therefore, the study provides essential information for estimating and enhancing the performance of thermoelectric modules such as thermoelectric generators both for small and large scale.

Road to advanced thermoelectric generators - Advances in Engineering
Basic principle and verification of Quasi-steady-state characterization method applied for thermoelectric generator modules

About the author

Mingzhe Rong received the Bachelor, Master and PhD degrees in electrical engineering from Xi’an Jiaotong University in China, in 1984, 1987 and 1990 respectively. He was a visiting scholar in the University of Liverpool from 1994 to 1995 and also a visiting professor in the University of Southampton in 2001. Now he is the professor in the Dept of electrical engineering at Xi’an Jiatong University, Deputy director of State Key Lab of Electrical Insulation and Power Equipment, and also the vice-principal of Xi’an Jiaotong University.

Prof. Rong’s interests include the HVDC interruption technology and its applications, mathematical simulation for switchgears and software package development, and condition monitoring & fault diagnosis for switchgears. He has published more than 200 papers on IOP, IEEE Trans, IET, IEICE, and Proceedings of the Chinese Society for Electrical Engineering and other journals, authorized invention patents more than 60 items and won 4 items of the National Science and Technology Awards of China.

He is the Chief Scientist of National Basic Research Program of China (973 Program), Principal Investigator of National Natural Science Fund for Creative Research Groups, IET Fellow and Vice Chair man of IET Xi’an Branch. He is also the winner of National Science Fund for Distinguished Young Scholars and Yangtze river scholars Distinguished Professor of Ministry of Education of China. He has acted as the (Vice) Chairman in international conferences for 5 times including IECPE-ST, IS-EMD, GD et al.

About the author

Yi Wu was born in 1975 in Jiangsu Province of China. He had learned the electrical engineering and got his PHD in 2006 from Xi’an Jiaotong University. From 2009 to 2010, he worked on the post doctor position for Delixi Corporation. Now he is a Professor in the School of Electric Engineering of Xi’an Jiaotong University.

Prof. Wu’s research has been centered on the electric arc plasma, DC short current interruption mechanism and new energy conversion technologies. He continues to explore new methods and theories on switch arc discharge, arc plasma properties, non-equilibrium plasma and analysis of breakdown in hot gas, arc characteristics controlling and high DC current interruption. He has 92 peer-reviewed papers published in international journals including J. Phys. D: Appl. Phys, IEEE Trans. on Plasma Sci., IEEE Trans. on Power Del. etc. (1 ESI paper of these).

He is also the editorial board member of Plasma Science and Technology, Scientific Committee member of GD Conference and member of CIGRE Working Group on DC switch technology. He has given 5 invited talks at international conferences organized by ICEPE, EMD, CICED, CZ Club, APCPST and 8 invited talks at seminars on the arc plasma or DC interruption to industries and international universities. He was awarded “The Second Prize of National Technical Invention”, ” First Prize of Natural Science of China’s Ministry of Education”, “First prize of technical invention in Shaanxi Province” and “The Excellent Talents of the New Century of the China’s Ministry of Education”.

About the author

Hailong He was born in Shaanxi Province, China, in 1987. He received the B.S. and Ph.D. degree in electrical engineering from Xi’an Jiaotong University, China, in 2010 and 2015, respectively. He is now a research assistant in the Dept of electrical engineering at Xi’an Jiaotong University.

Dr. He’s research fields have been involved in the new energy conversion technologies and applications, fault current limitation in DC power systems. He has published 13 peer-reviewed papers in the international journals including Energ. Convers. Manage., IEEE Trans. Power Del., J. Phys. D: Appl. Phys., et al. He was awarded “First prize of technical invention in Shaanxi Province” in 2015.

Reference

He, H., Liu, W., Wu, Y., Rong, M., Zhao, P., & Tang, X. (2019). An approximate and efficient characterization method for temperature-dependent parameters of thermoelectric modules. Energy Conversion and Management, 180, 584-597.

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