熱電能源產生器於廢熱再生能源之應用

Renewable Energy of Waste Heat Recovery by Thermoelctric Power Generator

徐振庭(Cheng-Ting Hsu)

指導教授 ： 饒達仁

國立清華大學/工學院/奈米工程與微系統研究所/博士(2011年)

摘要

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。

關鍵字

熱電 ； 能源產生器 ； 廢熱回收 ； 熱阻 ； 模擬 ； 排氣管 ； 席貝克常數 ； 熱接觸效應

並列摘要

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.

並列關鍵字

Thermoelectric ； Generator ； Waste heat recovery ； Thermal resistance ； Simulation ； Exhaust pipe ； Seebeck coefficient ； Thermal contact effect

參考文獻

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