بررسی تاثیر شکل سقف آتریوم بر دریافت روشنایی داخلی آتریوم در فضاهای آموزشی شهر تبریز

تامین روشنایی فضای آتریوم با بهره‌گیری مناسب از نور روز طبیعی از مواردی است که می‌بایست در طراحی این نوع از فضا مورد توجه قرار گیرد. نظر به اینکه فرم و ساختار سقف آتریوم می‌تواند بر نحوه‌ دریافت روشنایی طبیعی فضا تاثیرگذار باشد، مقاله‌ حاضر در پی بررسی تاثیر نوع و شکل سقف آتریوم بر میزان دریافت روشنایی داخلی آن در بناهای آموزشی اقلیم سرد شهر تبریز می‌باشد. جهت انجام پژوهش، آتریوم‌های دو طبقه با ابعاد 4*4، 6*6، 8*8 و 10*10 و پنج نوع سقف شامل سقف مسطح با نورگیری از بالا و جانبی، سقف دندانه‌ای، سقف شیب‌دار یک‌طرفه و دوطرفه با سطح شیشه‌خوری 90-50 درصد (با فاصله 10 درصد) طراحی گردید. با استفاده از نرم‌افزارهای اکوتکت و ردینس مدل‌های تحقیق بهینه‌سازی و میزان نور روز دریافتی، فاکتور نور روز و آتونومی نور روز از اول مهر تا آخر خرداد اندازه‌گیری گردید. دستاورد تحقیق حاکی از آن است که کمترین میزان نور دریافتی در آتریوم با سقف مسطح با نورگیر جانبی و بیشترین مقدار در آتریوم با سقف شیب‌دار دوطرفه ایجاد شده است. همچنین در آتریوم‌های با سقف مسطح (نورگیر از بالا)، سقف دندانه‌ای و سقف شیب‌دار یک‌طرفه، ابعاد 6*6 با سطح شیشه‌خوری 50 درصد و در آتریوم با سقف شیب‌دار دوطرفه، ابعاد 4*4 با سطح شیشه‌خوری 90 درصد امکان تامین مناسب روشنایی طبیعی روز فراهم می‌گردد. البته می‌بایست خاطرنشان کرد که نتایج به‌دست‌آمده تنها تحت تاثیر تغییرات شکل سقف، ابعاد پلان آتریوم و سطح شیشه‌خور سقف بوده و تاثیر سایر عوامل مورد کنکاش قرار نگرفته است.

Effect of Atrium Skylight Type on Atrium Interior Lighting in Educational Buildings in Tabriz, Iran

Atrium is referred to a wideopen space, which often has several floors and is covered with glass ceilings or large windows, or both. Atria are often used when the builtup area of the building is too high or the building’s southern facades are inaccessible or limited for lighting, so using sunlight should be the main consideration of their design. There are four types of atrium: centralized, semienclosed, attached, and linear. In this research centralized type is reviewed and a square plan atrium is chosen according to the studies. The dimensions of the selected plans for atriums are 4*4, 6*6, 8*8, and 10*10 meters and the height of the atrium is constant (9 meters). Since the form and structure of the skylight can affect how the atrium receives sunlight, this paper seeks to study the effect of the type and shape of the skylight on the amount of light received in the inner space of the atrium. This research has been carried out in the cold climate of Tabriz in Iran so the conditions of cloudy skies according to the climate of Tabriz are considered for simulation. In order to fulfill the objective of this study, first, the atrium and components which affect the design and the theoretical reviews were investigated and then the proportions of the model were obtained. In order to perform more detailed analysis, the effect of five different atrium skylights (1. flat roof with lighting from the top, 2. flat roof with lighting from sides, 3. roof with light scoops, 4. singlesided sloped roof, and 5. doublesided sloped roofs) on the interior lighting of the atrium have been compared. Also changing the amount of glazing surface of these skylights is another main variable of this research. Daylight Factor, Autonomy, Brightness (lux), and Sky Component are the factors that were measured by Ecotect Analysis and Radiance software. The results are compared and analyzed and have been illustrated in tables and graphs. The results demostrate that the shape of the skylight has a significant effect on the amount of light received inside the atrium. Suitable daylight factor and brightness for the atrium are achieved by a singlesided sloped roof with 90 percent of glazing and a doublesided sloped roof with 8090 percent of glazing while the dimensions of the atrium are 4m. For the atrium with dimensions of 6m, it is achieved by flat roof with lighting from the top, singlesided and doublesided sloped roof with 5060 percent of glazing and finally roof with light scoops with 5070 percent of glazing. There is a very high possibility of glare in larger atriums with this low, twostory height. It should be noted, however, that the results achieved are only affected by the changes in the roof shape, the proportions of the atrium and the amount of glass in the skylight, and factors such as the reflection of surfaces, the transmission of the surfaces, shading, height, and shape of the atrium and the effect of other conditions of the sky have not been considered.