Optimization Design And Performance Study Of Semiconductor Thermoelectric Power Generation Based On Waste Heat Recovery

Since the 21st century, the impact of the social showed vigorous upward in our country in the international community environment. However, energy shortage and environmental pollution appears frequently. In many aspects, conventional recovery mode is not realizable, but semiconductor thermoelectric can come true. It is very important in low temperature waste heat recovery in industry with thermoelectric generator technology.The steady working model of the single layer generator at small difference in temperature has been established through the present theory of thermoelectricity. Compared with the results of the experiment, summarizing and finding the most effective ways to improve and increase the working efficiency.The main content as following is based on the theory of thermoelectric power generation. Considering the temperature dependent properties of thermoelectric materials, an optimization designing model of thermoelectric unicouple was made. Utilizing the commercial FEM software ANSYS, the effect of thermoelectric length ratio, element cross section, contact resistance, cold side and hot side temperature on thermoelectric efficiency was analyzed, and the sensitivity analysis was also performed. The calculation result shows that the conversion efficiency of the thermoelectric generator can be effectively increased, and the theoretical efficiency of thermoelectric unicouple material is beside 10% when the temperature reached the range. The maximizing thermoelectric conversion efficiency was obtained and the effect of contact and thermal resistance and interfacial temperature on thermoelectric conversion efficiency was analyzed. The results show that the peak thermoelectric conversion efficiency is 9.61%,9.11%, and 8.40% respectively. When the thickness of contact layer is 0.1 mm, the peak efficiency decreases to 8.33%,7.87%and 7.11%. Efficiency is reduced about 13%-15%. Through the simulation analysis of actual project, it proves that the temperature difference power generation technology is fit for the waste heat recovery system.As one of main parts, the thesis designs and builds experimental platform using the low-grade heat source of small temperature difference according to the basic principle of TEG. This paper completes generator’s performance research under multi-operating modes and different temperature differences, obtains the reliable empirical data and summarizes a series of running rules. The study and applications on thermoelectric cooling is more mature than thermoelectric power generating. This article designs a low temperature difference power generation experiment based on the thermoelectric effect in the laboratory. Compare of the output power with different temperature difference, different cooling method, and explain the relationship between the output voltage of a single power module or several power modules connected in series and the temperature difference, simplify the calculation of the power output, pointed out that a single generation of modular components can be designed according to actual needs of different multi-module structure of series-parallel connection. Obtain various curves at different cases about the performances of the TEG.This paper also summarizes rules that the electricity generation performance parameters such as electromotive force, interface resistance, power and so on change along with factors of external circuit, temperature operating, geometrical size through the performance research of low-grade heat source semiconductor TEG, then summarizes performance of multi-module which is significant to the project practical application, obtains a series of useful conclusions, provides some practicable methods in the low-grade heat source directly using by the TEG.