熱電材料是一種能將熱能轉化為電能的半導體複合材料，在汽車排氣管或是工廠中的鍋爐、煙囪等數百度高溫環境中的能達到較高的能量轉換率。這些燃燒過後的高溫氣體，無論是經由車輛的排氣管或是工廠的煙囪導出，均含有大量熱能，很可惜的，上述排放出之熱能往往就散失到環境中，並無有效地利用，即所謂“廢熱”。本研究利用熱電能源產生器附包覆在如排氣管或是高溫熱風爐等發熱源外壁，可將熱能轉換為電能加以有效利用。其重點在開發廢熱回收系統的應用，利用電腦模擬及實測結果互相輔助，探討最佳設計製作條件；其中包含熱阻結構分析、熱電效應理論分析、壓力與接觸熱阻分析、熱場分析及散熱鰭片分析等，利用模擬軟體預測廢熱回收系統所能產出的發電功率，搭配系統實際組裝量測後所得之數據加以討論並改進，最後提出“等效席貝克常數”的概念，以等效的方式將溫度分佈不均、接觸熱阻效應及熱損失效應等現象簡化並包含於等效席貝克常數之內，來預測廢熱回收系統所能產出的發電功率，以幫助爾後的系統設計。

In this study, a system to recover waste heat comprised several thermoelectric generators (TEGs) to convert heat to electrical energy has been constructed. TEG modules are attached to the exhaust pipe of an automobile and furnace wall respectively to test and verufy the feasibility of waste heat recovery applications. Simulations and experiments for the thermoelectric module in this specific system were undertaken to assess the practicability of these applications. In order to estimate the temperature difference between thermoelectric elements, a thermal resistor network has been constructed. The results assist in modifying the actual temperature difference across the P- and N- couple. During simulations, heat sinks configurations and thermal field distributions are discussed, which helps to optimize the system design. Somehow, it is well known that the thermal contact effect dominates the thermoelectric properties, such as the power factor, ZT etc. Therefore, applying a suitable clamping pressure to reduce thermal contact effect is necessary. Finally, the concept of “effective Seebeck coefficient” has been proposed. This proposed value is a very important indicator which is expressing the behavior of the TEG module operating in the actual conditions we provided, and it can be used to predict the performance of the TEG module under any other condition. Throughout these simulations and experiments, the discussions of power generated with commercial TEG modules are presented. The results establish the feasibility of waste heat harvesting applications.

[1] D. M. Rowe and G. Min, "Optimisation of thermoelectric module geometry for waste heat electrical power generation.," Journal of Power Source, vol. 38, pp. 253-259, 1991.
[2] D. M. Rowe, ""Development of improved modules for the economic recovery of low temperature waste heat"," in Proc. Int. Conf. Thermoelectrics Dresden, Germany, 1997.
[3] D. M. Rowe and G. Min, "Evaluation of thermoelectric modules for power generation. ," Journal of Power Source, vol. 73, pp. 193-198, 1998.
[4] 工業材料雜誌, "http://www.materialsnet.com.tw," 2005.
[5] J. LaGrandeur, D. Crane, S. Mazar, and A. Eder, "Automotive waste heat conversion to electric power using skutterudite, TAGS, PbTe and BiTe," in Proc. Int. Conf. Thermoelectrics Vienna, Austria, 2006, pp. 343-348.
[6] L. D. Zhao, B. P. Zhang, J. F. Li, H. L. Zhang, and W. S. Liu, "Enhanced thermoelectric and mechanical properties in textured n-type Bi2Te3 prepared by spark plasma sintering " Solid State Sciences, vol. 10, pp. 651-658, 2008.
[7] T. Kajikawa and T. Onishi, "Development for advanced thermoelectric conversion system," in Proc. Int. Conf. Thermoelectrics Jeju, Korea, 2007, pp. 322-330.
[8] T. Caillat, J. P. Fleurial, G. J. Snyder, and A. Borshchevsky, "Development of high efficiency segmented thermoelectric unicouples," in Proc. Int. Conf. Thermoelectrics Beijing, China, 2001, pp. 282-285.
[9] J. G. Haidar and J. I. Ghogel, "Waste heat recovery from the exhaust of low-power diesel engine using thermalelectric generators," in Proc. Int. Conf. Thermoelectrics Beijing, China, 2001, pp. 413-417.
[10] A. S. Kushch, J. C. Bass, S. Ghamaty, and N. B. Elsner, "Thermoelectric development at Hi-Z technology," in Proc. Int. Conf. Thermoelectrics Beiling, China, 2001, pp. 422-430.
[11] 交通部, "http://www.motc.gov.tw/hypage.cgi?HYPAGE=stat01.asp."
[12] H.-Z. Technology, "http://www.hi-z.com/index.html."
[13] K. Ikoma, M. Munekiyo, K. Furuya, M. Kobayashi, T. Izumi, and K. Shinohara, "Thermoelectric module and generator for gasoline engine vehicles," in Proc. Int. Conf. Thermoelectrics Nagoya, Japan, 1998, pp. 464-467.
[14] 經濟部能源局-能源報導, "http://www.tier.org.tw/energymonthly/outdatecontent.asp?ReportIssue=9304&Page=14."
[15] S. Sampath, "Thermal spray applications in electronicsand sensors: past, present, and future," Journal of Thermal Spray Technology, vol. 19, pp. 921-949, 2010.
[16] L. Zuo, J. Longtin, S. Sampath, B. Li, and Q. Li, "NSF-DOE TE partnership:Integrated design and manufacturing of cost-effective & industrial-scalable TEG for vehicle applications," in DOE Thermoelectrics Workshop San Diego, CA, 2011.
[17] H. L. Talom and A. Beyene, "Heat recovery from automotive engine," Applied Thermal Engineering, vol. 29, pp. 439-444, 2009.
[18] K. Ono and R. O. Suzuki, "Thermoelectric power generation: converting low-grade heat intoelectricity," Journal of the Minerals, Metals & Materials Society, vol. 50, pp. 12-31, 1998.
[19] D. M. Rowe, "Thermoelectrics, an environmentally-friendly source of electrical power," Renewable Energy, vol. 16, pp. 1251-1256, 1999.
[20] J. Yang, "Potential applications of thermoelectric waste heat recovery in the automotive industry," in Proc. Int. Conf. Thermoelectrics Clemson, USA., 2005, pp. 155-159.
[21] C. Eisenhut and A. Bitschi, "Thermoelectric conversion system based on geothermal and solar heat," in Proc. Int. Conf. Thermoelectrics, 2006, pp. 510-515.
[22] M. Hasebe, Y. Kamikawa, and S. Meiarashi, "Thermoelectric generators using solar thermal energy in heated road pavement," in Proc. Int. Conf. Thermoelectrics Vienna, Austria, 2006, pp. 697-700.
[23] T. Ota, K. Fujita, S. Tokura, and K. Uematsu, "Development of thermoelectric power generation system for industrial furnaces," in Proc. Int. Conf. Thermoelectrics Vienna, Austria, 2006, pp. 354-357.
[24] C. Lertsatitthanakorn, "Electrical performance analysis and economic evaluation of combined biomass cook stove thermoelectric (BITE) generator," Bioresource Technology, vol. 98, pp. 1670-1674, 2007.
[25] K. Qiu and A. C. S. Hayden, "Development of a thermoelectric self-powered residential heating system," Lournal of Power Sources, vol. 180, pp. 884-889, 2008.
[26] B. Poudel, Q. Hao, Y. Ma, Y. Lan, A. Minnich, B. Yu, X. Yan, D. Wang, A. Muto, D. Vashaee, X. Chen, J. Liu, M. S. Dresselhaus, G. Chen, and Z. Ren, "High-thermoelectric performance of nanostructured bismuth antimony telluride bulk alloys," Science, vol. 320, pp. 634-638, 2008.
[27] A. I. Boukai, Y. Bunimovich, J. Tahir-Kheli, J.-K. Yu, W. A. Goddard Iii, and J. R. Heath, "Silicon nanowires as efficient thermoelectric materials," Nature, vol. 451, pp. 168-171, 2008.
[28] A. I. Hochbaum, R. Chen, R. D. Delgado, W. Liang, E. C. Garnett, M. Najarian, A. Majumdar, and P. Yang, "Enhanced thermoelectric performance of rough silicon nanowires," Nature, vol. 451, pp. 163-167, 2008.
[29] Y. A. CENGEL, HEAT AND MASS TRANSFER, A Practical Approach, 3rd Edition.
[30] Incropera, DeWitt, Bergmann, and Lavine, Fundamentals of Heat and Mass Transfer, 6th Edition.
[31] K. Azar and B. Tavassoli, "How much heat can be extracted from a heat sink," in Electronics Cooling. vol. 9, 2003, pp. 30-36.
[32] M. Lyengar and A. Bar-Cohen, "Design for manufacturability of forced convection air coolie fully ducted heat sinks," in Electronics Cooling. vol. 13, 2007, pp. 12-18.
[33] R. E. Simons and I. Corporation, "Calculation corner: estimating parallel plate-fin heat sink thermal resistance," in Electronics Cooling. vol. 9, 2003, pp. 8-9.
[34] Z. Luo, "A simple method to estimate the physical characteristics of a thermoelectric cooler from vendor datasheets," in Electronics Cooling. vol. 14, 2008, pp. 22-27.
[35] 饒達仁, 徐振庭, and 游本懋, "熱電能源產生器於車輛排氣管廢熱回收之應用," in 中華民國第三十二屆全國力學會議(The 32th Conference on Theoretical and Applied Mechanics), National Chung Cheng University, ChiaYi, Taiwan, R.O.C, 2008.
[36] Da-Jeng Yao, Ke-Jyun Yeh, Cheng-Ting Hsu, Ben-Mou Yu, and J.-S. Lee, "Efficient reuse of waste energy," in IEEE Nanotechnology Magazine. vol. 3, 2009, pp. 28-33.
[37] Cheng-Ting Hsu, Da-Jeng Yao, and B.-M. Yu, "Application of thermoelectric waste heat recovery from automobiles," in Proceedings of Micro/Nanoscale Heat and Mass Transfer International Conference (MNHMT2009), Shanghai, China, 2009.
[38] Cheng-Ting Hsu, Da-Jeng Yao, Ke-Jyun Yeh, and B.-M. Yu, "Renewable energy of waste heat recovery system for automobiles," Journal of Renewable and Sustainable Energy, vol. 2, 2010.
[39] Y. Y. Hsiao, W. C. Chang, and S. L. Chen, "A mathematic model of thermoelectric module with applications on waste heat recovery from automobile engine," Energy, vol. 35, pp. 1447-1454, 2010.
[40] E. F. Thacher, B. T. Helenbrook, M. A. Karri, and C. J. Richter, "Testing of an automobile exhaust thermoelectric generator in a light truck," Proc. Inst. Mech. Eng. Part D-J. Automob. Eng., vol. 221, pp. 95-107, 2007.
[41] X. Niu, J. Yu, and S. Wang, "Experimental study on low-temperature waste heat thermoelectric generator," Journal of Power Sources, vol. 188, pp. 621-626, 2009.
[42] X. Gou, H. Xiao, and S. Yang, "Modeling, experimental study and optimization on low-temperature waste heat thermoelectric generator system," Applied Energy, vol. 87, pp. 3131-3136, 2010.
[43] C. T. Hsu, G. Y. Huang, H. S. Chu, B. Yu, and D. J. Yao, "Experiments and simulations on low-temperature waste heat harvesting system by thermoelectric power generators," Applied Energy, vol. 88, pp. 1291-1297, 2011.
[44] R. E. Simons, "Using a matrix inverse method to solve a thermal resistance network," in Electronics Cooling, 2009.
[45] R. Wilcoxon, "Calculation corner: a spreadsheet based matrix solution for a thermal resistance network: part 1," in Electronics Cooling, 2010.