The Characterization Of Semiconductor Thermoelectric Generator

The "13th Five-Year" is the decisive stage period for China to change energy development strategy from the original amount of growth to enhance the quality, and the development of green and renewable energy and improving energy efficiency are the effective guarantee of improving the quality of energy and main technical measures. The semiconductor thermoelectric power generation technology is an effective device which directly converts low grade heat energy into high quality electric energy. Therefore, the research on key technology of semiconductor thermoelectric power generation system in low grade energy has important significance. Basing on the production and utilization state of the low grade heat source in china. This paper used the method of combining numerical simulation and experiment to test and analyze the performance of thermoelectric power generation system and get some useful data. Putting the focus on the analysis model of temperature difference power generation module, the heat transfer characteristics of the substrate and the effect on the output characteristics. At the same time, the numerical model closing to the actual working condition is established, considering the air flow heat transfer problem of the gap between thermoelectric units. The influence of the structures and sizes of thermoelectric elements on the performance of thermoelectric generator was explored. And comparing the effect of different heat radiation field on the output power and conversion efficiency of thermoelectric power generation system, which is helpful to improve the performance and application of semiconductor thermoelectric power generation system. The main contents of this paper are as follows:1. Using the method of thermal resistance network analysis, comparison analysis and experimental testing, the cold end of the semiconductor thermoelectric module using forced air cooling and forced liquid cooling the distribution of thermal resistance of each part, and the effect on the heat flux density, output power and output voltage of the component. Basing on the properties of heat source (constant heat flux and constant temperature), the using environment and the demand of the load characteristics, and combining the engineering economy, design suitable thermoelectric module structure and thermoelectric power generation system of the radiation field. To lay a theoretical basis for the further optimization of the thermal resistance of semiconductor thermoelectric generation system.2. A new type of semiconductor thermoelectric generation model is proposed, which considering the influence of the heat transfer in the closed cavity between the thermoelectric units in the numerical simulation of the thermoelectric generation process. Also based on the finite element numerical calculation method and using ANSYS numerical simulation software to carry out the numerical simulation of the temperature field and voltage field of different electric arms and models of thermoelectric generation models, and the simulation results are analyzed in three dimensional steady state. The results show that the output power and energy conversion efficiency of the thermoelectric generator are increased with the increase of the logarithm of the thermoelectric unit, and the more the logarithms are, the greater the output power is, and the higher the energy conversion efficiency is. Through the comparison of the performance of three different cross-sectional areas power unit thermoelectric module, it is concluded that the power unit output voltage, power and energy conversion efficiency were improved with the increase of the cross-sectional areas of the thermoelectric elements, and the more the temperature difference of the hot end and the cold end of the thermal power unit is, the greater the increase amplitude is, but the internal resistance of the thermoelectric generation chips is decreased with the increase of galvanic arm cross-sectional area; These results have important significance for the comprehensive study of the structure optimization and the concrete rules of thermoelectric components.3. Establish a test system for semiconductor thermoelectric power generation module, and design a voltage stabilizing module of low voltage auxiliary start. Analyze the effect of heat radiation field, heat source temperature and load resistance of the semiconductor thermoelectric power generation system on the thermoelectric properties. By comparative analysis, for the constant temperature heat source, the method of forced liquid cooling mode is more benefit to improve the output power of the temperature difference power generation module than the forced air cooling mode and the output power is up to 24.4%.To sum up, the research on the subject of the key technology and the optimization plan of semiconductor thermoelectric power energy conversion show that, the semiconductor thermoelectric power generation technology as a low-grade heat recovery utilization technology has a unique advantage. Which showed activity in energy saving and environmental protection, distributed energy utilization field. The content of the thesis is only part of research and application of the semiconductor thermoelectric power generation technology, the achieved research results have contributed to the application and popularization of the thermoelectric generation technology. With the continuous development and breakthrough of thermoelectric power generation technology and thermoelectric materials research, the semiconductor thermoelectric power generation technology is expected to become a powerful branch of new energy power generation technology.