用於日光傳輸之高傳輸效率光導耦合器的研究與設計

The study and design of light guide couplers with high transmission efficiency in daylight transmission

沈易達(Yi-Ta Shen 沈易達)

指導教授 ： 徐巍峰

國立臺北科技大學/電資學院/光電工程系研究所/博士(2013年)

https://doi.org/10.6841/NTUT.2013.00205

摘要

在過去數十年中提出的太陽能應用技術，主要分為熱、發電與照明三大種類，部份種類都需要利用光學傳輸系統。而太陽能的光學傳輸系統由光收集、光引導與光輸出等元件組成。一般而言，集光系統通用於所有太陽能應用之中，僅少數應用不需要光引導例如熱應用、直接發電應用等。而光輸出部份通常都搭配在集光器或光引導系統之末端，主要功能在於提供光輸出的均勻度和高集中度。
使用太樣能的關鍵在於效率，而將太陽光直接應用在建築物的室內照明，可以減少不同形式的能量轉換損失，因此可增加太陽能的使用效率。但多數文章中未曾見到討論傳輸時的損失問題，僅僅考慮末端效率是否達到能使用的強度。
若要提供足夠光量的太陽光在照明系統中，集光器和耦合器的數量一定不少，但是目前耦合器的耦合效率都很低。為了提高太陽光在傳導系統中的傳輸效率，需要針對效率損失較嚴重的光耦合器進行分析，而本論文將建立光線在傳導系統中各個部份的數學公式，以數值分析為輔的方法來設計出高效率的光耦合器用於日光的室內照明傳輸。
根據分析結果，本文推薦使用耦合角30°-35°，此範圍在非對稱與對稱式結構的總耦合效率屬於最高値區段，約54%，如果集光角越小越能提供更高的耦合效率，最高可達96%。而以多分枝做為考量時，本文推薦的光耦合器為非對稱式耦合器，其耦合角度為80°，而分枝收光角度集中到-80°到-90°，其耦合效率最高可達77%。

關鍵字

光耦合器 ； 日光引導 ； 日光照明 ； 耦合效率

並列摘要

The application of solar energy in recent years inciude: heat, electricity, illumination, and some of these need to use an optical transmission system. The optical transmission system is composed of the collecting, transmission, and output parts. Most solar systems in the application of solar-thermal and photovoltaics need the optical transmission system to transfer the collected daylight to the energy-transformed part. The function of the exporting part, connected to the transmission system, is to provide the light output uniformity and high concentration.
The efficiency of daylight utilization is the key factor in solar systems. Because direct application of solar in indoor lighting reduce the loss of energy transfer, the efficiency of solar energy can be highly increased.
A great amount of collections and transmissions are needed to provide enough light for indoor lighting. However, the efficiency of current couplers is low. In order to improve efficiency of the transmission system, we analysis the loss of couplers. In this thesis, we establish the mathematical model of the transmission system, and design the couplers with high efficiency for indoor lighting by using the mathematical model.
Based on the results, we recommend coupling angles between 30° to 35°, because the couple efficiencies of the asymmetric and the symmetrical are the highest (54%). In addition, the asymmetric structure of the coupling angle of 80° provides the efficiency of 77%, when the branch of collect angle at -80° to -90°.

並列關鍵字

Light coupler ； sunlight guiding ； daylighting ； coupling efficiency

參考文獻

[1] V. V. Tyagi, S. C. Kaushik, and S. K. Tyagi, "Advancement in solar photovoltaic /thermal (PV/T) hybrid collector technology," Renewable and Sustainable Energy Reviews, vol. 16, 2012, pp. 1383-1398

[5] P. B. L. Chaurasia, “Solar water heaters based on concrete collectors,” Energy, vol. 25, 2000, pp. 703-716.

[6] S. A. Kalogirou, ”The potential of solar industrial process heat applications,” Appl Energy, vol. 76, 2003, pp. 337-361.

[7] S. A. Kalogirou, ”Solar thermal collectors and applications,” Progress in Energy and Combustion Science, vol. 30, 2004, pp. 231-295.

[8] S. B. Riffat, X. Zhao, and P. S. Doherty, “Developing a theoretical model to investigate thermal performance of a thin membrane heat-pipe solar collector,” Applied Thermal Engineering, vol.25, 2005, pp. 899-915.