不同型式光纖與集光器搭配之效率測試

Test of the Efficiency of the Concentrator with Different Types of Optical Fiber

彭彥凱(Yen-kai Peng)

指導教授 ： 吳俊諆

國立中央大學/工學院/能源工程研究所/碩士(2007年)

摘要

太陽集光器在太陽能應用佔有重要的地位，近年來它的應用朝向將光經由光纖傳導至室內再轉換成其他形式能量，這種方式有其彈性但其實用性尚待評估。因此本文探討使用拋物面碟式集光器搭配光纖，將集光器聚焦的光經由光纖傳輸到遠端的可行性。
光纖—集光器的主要兩個光學元件為光纖與反射鏡組（做為集光器），反射鏡組包含拋物面主反射鏡與平面二次反射鏡。目前光纖的光學特性和材料性質與集光器的特性在搭配時會有限制，特別是主反射鏡的直徑、曲率大小與光纖數值孔徑等參數，此外操作溫度亦會影響輸出功率，這些因素都會影響光纖的光傳輸效率。因此本文使用兩種反射鏡組搭配三種不同形式的單光纖（塑膠和石英）與兩種石英光纖束，光纖的長度可達150 cm。由量測與估算的光傳輸功率計算光傳輸效率。在單光纖形式中，有緩衝層石英光纖的傳輸效率最好，光纖傳輸長度為120 cm的光傳輸效率為77%-80%。而光纖束目前製作技術不理想，單光纖製作成光纖束後，光強度便會大幅下降。本文亦對石英光纖的輸出功率受溫度效應作探討，在低操作溫度範圍(25oC - 95oC)，發現此溫度範圍內石英光纖輸出功率穩定。

關鍵字

傳輸效率 ； 功率量測 ； 光纖束製作 ； 太陽集光器

並列摘要

Solar concentrator is an important device in the application of solar energy, and one of its applications is utilize the optical fiber to transport the concentrated light into the indoor for converting the solar energy to other form of energy. Such arrangement provides flexibility and yet its practical implementation remains to be investigated. Thus, this work is a feasibility study of transmitting the concentrated light from a concentrator through the optical fiber.
Present arrangement of the fiber-concentrator consisted of a parabolic dish (the primary mirror) and a flat secondary mirror, and various forms of optical fiber (plastic and quartz) up to the length of 150 cm. There is some mismatch between the optical and material characteristics of fibers and the mirrors used in the concentrator, especially the diameter and the curvature of primary mirror, and the numerical aperture of the fiber. In addition, the operating temperature will affect the output power from the fiber. This study uses two types of primary mirror, three types of single fiber and two modes of quartz-fiber bundle. The transmitting efficiency is calculated from both the measured and predicted light power through the light path of the concentrator-fiber. In the case of single fiber, the quartz-fiber with the buffer layer has best efficiency; it’s efficient is 77-80% for a 120-cm length of transmitting length. Due to imperfect fabrication of the fiber bundle, the light intensity of the fiber bundle drop significantly compare with that of the single fiber. Finally, the measured light power was stable in the range of low operating temperature (25oC - 95oC).

並列關鍵字

power measurement ； solar concentrator ； fabrication of fiber bundle ； transmitting efficiency

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