- 學位論文
溫差效應對太陽能熱發電機效率之影響
Temperature Effect on the Performance of Solar Thermal Power Generation
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摘要
本研究目的為架設一個太陽能熱發電系統，並討論太陽能熱發電系統在不同溫差系統之性能表現。本系統包含以菲涅爾透鏡為主之聚光系統；及由史特林引擎、發電機所組成之發電系統；以齒輪作為史特林引擎與發電機間動能的轉換。此外也包含冷卻系統，利用設計之水冷裝置對史特林引擎作冷卻，提高引擎兩端溫差。本研究分別對所架設太陽能熱發電系統作室內及戶外系統性能測試，過程中，以Labview軟體所撰寫的程式作為監測系統，監測系統發電量及效率。 在室內實驗，分別以加熱器及利用鹵素燈模擬太陽光源並透過菲涅爾透鏡聚焦於史特林引擎上進行加熱。在加熱器實驗中，加冷卻水約7.6℃將溫差端維持在約在75℃後，系統效率最高增加2.4倍。在鹵素燈模擬太陽光源實驗中，加入約10.6℃冷卻水後溫差約維持在53℃，系統輸出總能量最高增加2倍。 由戶外實驗量測結果可知系統為一動態系統，故以系統識別方式進行數據分析，藉此判別系統分別受何種因素影響。系統在分析時分為二個子系統分別進行分析。第一子系統為照度與史特林引擎加熱端溫度之關係，而以史特林引擎之加熱端溫度和低溫端溫度對最後發電機輸出電壓之關係作為第二子系統。由第一子系統分析之結果，可知戶外實驗除照度外，外界自然對流亦會對史特林引擎加熱端溫度造成影響。第二子系統分析結果，系統電壓輸出預測可藉由史特林引擎兩端溫差透過一轉移函數而得知趨勢。於論文最後可整理出影響太陽能熱發電系統效率之因素。
並列摘要
The aim of this thesis is to establish a small-scale solar thermal power generation system, and to investigate the efficiency-affecting factors. Fresnel lens is used as a concentrator to collect sunlight from larger area, and the power conversion unit consists of a Stirling engine and a power generator. Cooling device is also integrated into the Stirling engine so that larger temperature difference can be achieved. Finally, system output power and system efficiency were both monitored in the indoor and outdoor experiments. The indoor experiments are divided into two parts. The first one is using heat gun as the energy source. Experimental results shows that system efficiency increases 2.4 times when 7.6℃cooling water is injected. The second experiment uses Halogen lamp as virtual sunlight. Results show that total output energy of the system is increased 2 times by injecting 10.6℃cooling water. Experiments show that this system is a dynamic system. Therefore, the analysis of data is carried out by means of system identification. In analysis process, the system is divided into two parts. The first part discusses about relationship between illumination and the hot side temperature of the Stirling engine. Results show that the hot side temperature of the Stirling engine is strongly affected by not only illumination and but also natural convection. The second part is about temperature effect on the system output voltage. Results show that the trend of output voltage can be predicted by the temperature difference alone through a transfer function. Finally, six efficiency-affecting factors can be summarized.
參考文獻
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