自然光環境下其光源至少包括直、漫、反射光等光源，一般來講直射光太強容易產生眩光及熱輻射對自然採光來講不易利用，故常以遮陽設施遮蔽其強烈的光源維持室內光環境一恆常的漫射光源，但由於漫射光源強度過低常無法提供建築物內周區足夠的照度值，台灣在夏秋兩季是相當高熱及潮濕的，維持建築物運作是需要消耗大量能源，在此用電高峰載時期剛好也是高日照率時節，在這樣的氣候條件下很自然地會利用外遮陽設施來降低直射光直接照射室空間，在此若能同時考量運用導光板之導光特性來加深採光深度，會是同時改良內週區照度及採光品質的重要方法，如此才能在高熱時期時同時兼顧節能效果及提供建築物足夠的照度水準。
本研究以建築設計應用遮陽導光板強化晴天空自然光利用之觀點，試圖建立晴天空環境下水平遮陽導光板對室內照度之簡易推估式，從基本的自然採光理論如光輻射法、相對晝光率及全天空可及漫射光度模型等進行分析及簡化，進而推導晴天空環境下室內照度簡易推估式，並結合晝光實驗研究較能表達實際採光情形之優點，比對及分析晝光模型實測數據來修正本研究建立之室內照度簡易推估式，以此提高推估式之準確度及應用性，進而提出最佳晴天空環境下室內照度簡易推估模式供建築採光設計時運用，而所建立之推估式及運用模式亦可作為後續相關研究發展之基礎式。
本文結合理論計算及模型實測法之優點，以此建立晴天空環境下室內照度簡易推估模式並提供建築採光設計時運用，其以手算應用之觀點在不失真之條件下進行簡化，故能利用最被廣泛使用之Microsoft Excel軟體作為簡算表，輸入簡易推估式進行相關之計算，除能使建築採光設計者了解採光行為之因果關係，掌握變因影響趨勢，更能量化設計結果提高設計準確性。
綜合相關應用分析可以了解本研究所建立之室內照度推估模式，在已納入推估之實驗變因及邊界條件下，透過建立之室內照度簡易推估式可以預測室內任一點在各種變因改變下之照度值包括開窗率、相對太陽高度、方位角及深度比甚至遮陽型式，不再受實驗法所建制之變因條件限制，如此可以補足實驗時所缺漏之模組及數據，故在同樣的數據資料要求下大量降低及縮短實驗所需之時間、空間、人力及設備成本，如此簡易、方便使用且又具一定精準性之推估模式，對於推廣運用遮陽導光設施來提高採光效能及省能效益無非係一有效之工具。

Natural daylight including directional sunlight, diffused skylight and reflected light at least. Directional sunlight is difficult to apply to room lighting, because its illuminance value is too high to cause overheating and glare. Shading device installation generally relies primarily on shelter from directional sunlight, providing constant room-diffused skylight. The drawback of this method is that diffused skylight is almost insufficient in the core of a building, The climate of Taiwan is hot and humid in both summer and in autumn. The peak electric power load for the island also increases during this period. Maintaining a building during this period, when there are high levels of sunshine, requires high energy-consumption. Given this climate, it is natural to assume that outside shading devices should first be employed, if they can be applied to reduce the penetration of direct beams of sunlight through windows, and to promote an area of natural daylight, especially towards the back of rooms and opposite their windows. These measures in turn reduce building cooling load and electric power consumption. Applying the reflective qualities of a shading device to increase the depth of daylight penetration is important when attempting to improve both daylight level and quality in the deep areas of a room. Furthermore, the shading device saves energy by exploiting the bright daylight received during periods of intense heat, and thus can provide sufficient illuminance to a building.
The purpose of the research is to build a simple equation, for easily evaluating indoor illuminance applied in horizontal shading devices and light shelves design under clear sky conditions. Analyse and simplify from the basic natural daylighting theory such as Optical radiation method, Relative daylight factor and Global diffuse daylight availability model etc., and then derive the simple estimating equation of indoor illuminance under clear skies. Combine the advantage of experiment, it can relatively express the real daylighting situation while testing under clear skies, and analyse the data of experiment to revise this simple estimating method of indoor illuminance, so as to improve the accuracy and applications of the estimating method. And then propose that the most properly simple estimating method for lighting design to apply. This estimating equation and utilizing model can conduct more relevant researches in the future.
This article combines the advantages of daylighting calculations and physical models, in order to establish a simple way to estimate the indoor illuminance under clear sky conditions, which could be applied to the utilization of indoor daylighting of any building. Besides, under the none distorted condition, the hand calculated viewpoint of the application also contains the simplification, therefore we can use the popular Microsoft Excel software to carry on relevant calculation, which not only make the designer of the indoor daylighting to understand the natural lighting behaviour, master the changes of the tendency of any variable, but also energize the designing result to enhance the accuracy.
Through introducing the boundary condition and changeable factors to the above mentioned analysis, we may understand the illuminance of indoor daylight calculating model established by this research, which could help us to predict any lightening value changed by whichever variable, including Win, Alt, Az and Dep, even the shading style. So we are no longer restrained by the limitation set by the research model, so to compensate the module and data missed during the experiment, therefore time, space, human resources and the cost of experiment will be massively reduced and under the similar data material requested. Such simple, convenient estimation type with certain accuracy will enhance the promotion of the use of the facilities of natural lighting potency and energy saving, the beneficence of this effective tool would be invaluable.

參考文獻

[1] R.P. Leslie. Capturing the daylight dividend in buildings: why and how? Building and Environment 2003;38（2）:381-385.
[2] Alfonso Soler, Pilar Oteiza. Light shelf performance in Maidrid, Spain. Building and Environment 1997;32（2）:87-93.
[3] Santigo-Tomas Claros, Alfonso Soler. Indoor daylight climate-influence of Light shelf and model reflectance on Light shelf performance in Maidrid for hours with unit sunshine fraction. Building and Environment 2002;32（6）:587-598.
[4] Michelle Foster, Tadj Oreszczyn. Occupant control of passive systems: the use of venetian blinds. Building and Environment 2001;36（2）:149-155.
[5] A. K. Yener. A method of obtaining visual comfort using fixed shading devices in rooms. Building and Environment 1999;34（3）:285-291.
[6] J, Waewsak, J, Hirunlabh, J, Khedari, U.C. Shin. Performance evaluation of the BSRC multi-purpose bio-climatic roof. Building and Environment 2003;38（11）:1297-1302.
[7] David Jenkins, Tariq Muneer. Modelling light-pipe performances-a natural daylighting solution. Building and Environment 2003;38（7）:965-972.
[8] Aris Tsangrassoulis, Mat Santamouris. D. Asimakopoulos. Theoretical and experimental analysis of daylight performance for various shading systems. Energy and Buildings 1996;24（3）:223-230.
[9] Victor M. Gomez-Munoz, Miguel Angel Porta-Gandara. Simplified architectural method for the solar control optimization of awnings and external walls in houses in hot and dry climates. Renewable Energy 2003;28（1）:111-128.
[10] P.J. Greenup, I.R. Edmonds. Test room measurements and computer simulations of the micro-light guiding shade daylight redirecting devices. Solar Energy 2004;76（1）:99-109.
[11] P. R. Tregenza. Mean daylight illuminance in rooms facing sunlit streets. Building and Environment 1995;30（1）:83-89.
[12] 林冠州 《居室空間水平遮陽暨導光版在直射光環境下之採光效能評估》碩士論文，私立淡江大學，私人出版 1998
[13] 黃俊程 《居室空間格柵遮陽版在直射光環境下之採光效能評估》碩士論文，私立淡江大學，私人出版 1998
[14] 陳乾隆 《自然光環境下垂直遮陽板之採光效能評估》碩士論文，私立淡江大學，私人出版 1999
[15] 張弘樺 《建築光環境塑造之全天空太陽輻射能量與可及漫射光度模型》
碩士論文，私立淡江大學，私人出版 2000
[16] 林憲德、賴榮平、周家鵬《建築物節約能源設計手冊》內政部建築研究所籌備處 1991：118-122
[17] Commission International de L'Eclairage（CIE）. Standardization of luminance distribution on clear skies. CIE Publication No. 22, 1973.
[18] IES Calculation Procedures Committee. Recommended practice for the calculation of daylight availability. Journal of the Illuminating Engineering Society. 1984;13（4）:381-392.
[19] 張鏡湖 《台灣地區全年太陽輻射之分佈》行政院國家科學委員會研究案
NSC-74-0202-M0002-07 國立臺灣大學地理系 1986：2-10
[20] 曾文塏 《全天空太陽輻射及漫射光度可及之探討》碩士論文，私立淡江
大學，私人出版 1999
[21] Norio Igawa, Hiroshi Nakamura. All sky model as a standard sky for the simulation of daylit environment. Building and Environment 2001;36（6）:763-770.
[22] Surapong Chirarattananon, Pipat Chaiwiwatworakul, Singthong Pattanasethanon. Daylight availability and models for global and diffuse horizontal illuminance and irradiance for Bangkok. Renewable Energy 2002;26（1）:69-89.
[23] Ernesto Betman. Daylight calculations using constant luminance curves. Renewable Energy 2005;30（2）:241-257.
[24] 林憲德、賴榮平、周家鵬《建築物節約能源設計之指標與基準》內政部
建築研究所籌備處 1991：118-122
[25] 游義琦《遮陽、晝光利用與空調綜合省能效果評估》碩士論文，國立成功大學，私人出版 1990
[26] 周家鵬、周鼎金《建築物採光與照明省能設計方法研究》台北：經濟部
能源委員會能源 研究發展基金報告 1992
[27] 陳致和《水平遮陽板及導光版之採光效能之研究》碩士論文，私立淡江大學，私人出版 1995
[28] 廖蓮輝《格柵遮陽板之遮蔽效果與採光效能關係研究》碩士論文，私立淡江大學，私人出版 1996
[29] Francisco Arumi-Noe. Algorithm for the geometric construction of an optimum shading device. Automation in Construction 1996;5（3）:211-217.
[30] 游璧菁《建築技術規則中採光規範之研究－以住宅及旅館居住單元空間為
對象》碩士論文，私立淡江大學，私人出版 1992
[31] 劉澄泰《建築物垂直遮陽板之採光與遮蔽效能綜合研究》碩士論文，私立淡江大學，私人出版 1997
[32] 林清政《學校綜合體育館屋頂採光探討－以大專院校為例》碩士論文，私
立淡江大學，私人出版 1998
[33] Pilar Oteiza, Alfonso Soler. Experimental analysis for Madrid, Spain, of a simple graphic daylight calculation method based on the CIE standard overcast sky. Building and Environment 1997;32（4）:363-366.
[34] B. Calcagni, M. Paroncini. Daylight factor prediction in atria building designs. Solar Energy 2004;76（6）:669-682
[35] Seung-Ho Yoo, Eun-Tack Lee. Efficiency characteristic of building integrated photovoltaics as a shading device. Building and Environment 2002;37（4）:615-623.
[36] 賴榮平、林憲德、周家鵬《建築物裡環境》台北，六合出版社 1991
[37] C.P. Chou A Mathematical Model of Building Base on First Principles of Astrometry, Solid Geometry and Optical Radition Transfer. P.H.D.，Virginia Polytechnic Inst.&.State university.
[38] 郭俊聲《建築採光計劃－在定量曇天空下探討垂直面之照度》碩士論文，
私立中原大學，私人出版 1989
[39] 高志揚《建築物室內採光計劃之研究考慮窗面條件下直射光之分析》碩士
論文，國立成功大學，私人出版 1989
[40] 張榮峰《建築臨棟關係之採光效能影響研究》碩士論文，國立成功大學，
私人出版 1995
[41] 溫國忠《建築物自然採光性能與開窗法省能之研究-以單一多重變數迴歸分析建立理論模型》碩士論文，私立淡江大學，私人出版 1990
[42] 雷祖康《建築物外週區採光與照明綜合效能評估作業》碩士論文，私立淡江大學，私人出版 1993
[43] C. Schweizer, U. Eicker, K. Lomas. Dynamic calculation of daylighting in urban structures. Renewable Energy 1998;15（3）:360-363.
[44] Paul Littlefair Daylight Prediction In Atrium Buildings.Solar Energy 2002；73（2）：105-109.
[45] Commission International de L'Eclairage（CIE）. Daylight. CIE Publication No.16, 1970.
[46] C.L. Cheng, C.L. Chen, C.P. Chou and C.Y. Chan, “A mini-scale modeling approach to natural daylight utilization in building design”, Building and Environment 2007;42（1）:372-384.
[47] 詹肇裕《太陽光電技術應用於建築設計之評估與策略研究》博士論文，國立台灣科技大學，私人出版 2005
[48] Wang, Gene C.T. Applied physics for architecture. Tai Long book Co. Taipei, Taiwan; 1987, p. 446-456.
[49] 詹慶旋《建築光環境》台北，淑馨出版社 1991
[50] Laurent Michel, Jean-Louis Scartezzini. Implementing the partial daylight factor method under a scanning sky simulator. Solar Energy 2002;72（6）:473-492.
[51] A. Tsangrassoulis, K. Niachou, N. Papakostantinou C. Pavlou, M. Santamouris. A numerical method to estimate time-varying values of diffuse irradiance on surfaces in complex geometrical environments. Renewable Energy 2002;27（3）:427-439.
[52] Salvo Sciuto. Solar control: an integrate approach to solar control techniques. Renewable Energy 1998;15（3）:368-376.
[53] Katerina Tsikaloudaki. A study on luminous efficacy of global radiation under clear sky conditions in Athens, Greece. Renewable Energy 2005;30（