بررسي تأثير سايه‌ بان‌هاي متحرك الحاقي به فضاهاي نيمه‌ باز بر مصرف انرژي سالانه‌ ساختمان‌هاي مسكوني تهران

An Analytic Study of the Effect of the Movable Shading Devices Attached to Semi-Open Spaces on the Annual Energy Consumption: A Case Study of Residential Buildings in Tehran

يكي از راهكارهاي مؤثر در معماري گذشته‌ ايران، بهره‌گيري از سايه‌بان‌هاي متحرك به عنوان يكي از سامانه‌هاي غيرفعال ساختماني بوده ‌است كه كاربرد گسترده‌اي داشته و مي‌توان در معماري امروز از آن به منظور بهبود عملكرد حرارتي فضاهاي نيمه‌باز بهره گرفت. در اين پژوهش، براي اعتبارسنجي شبيه‌سازي از مقايسه نتايج اندازه‌گيري تجربي استفاده ‌شده است. شبيه‌سازي حرارتي در نرم‌افزار انرژي‌پلاس نسخه 8.9 صورت گرفت. براي شبيه‌سازي، عمق‌ فضاي نيمه‌باز، اندازه‌ سطح بازشوي ديوار مجاور فضاي نيمه‌باز و ضريب هدايت حرارتي آن در دو نوع بالكن و ايوان، به عنوان متغير در نظر گرفته ‌شدند و تأثير الحاق سايه‌بان با لوورهاي متحرك و پوشش شيشه‌اي متحرك بر عملكرد حرارتي فضاي مجاور بالكن و ايوان بررسي شد. نتايج شبيه‌سازي حاكي از آن بود كه در اوقات گرم سال، استفاده از سايه‌بان با لوورهاي باز و در اوقات سرد سال، به‌ كار بردن پوسته‌ شيشه‌اي متحرك در جداره‌هاي باز، سبب ارتقا عملكرد حرارتي فضاي مجاور فضاي نيمه‌باز است. در اوقات گرم سال، تأثير سايه‌بان الحاقي بر بهبود عملكرد حرارتي اتاق، با تغيير عمق تفاوت چنداني نمي‌كند ولي در اوقات سرد سال مي‌تواند تا 30% بارهاي حرارتي را كاهش دهد. در انتها نيز دستورالعملي براي طراحي سايه‌بان‌هاي متحرك و الحاقي به فضاهاي نيمه‌باز ساختمان‌هاي مسكوني شهر تهران ارائه گرديد.

One of the most important components of a building that influences physical properties, environmental behavior and responses, and energy consumption is the building envelope. Therefore, accurate decision-making in this regard will be of particular importance. Most of the measures taken to reduce energy consumption in buildings are somehow active and mechanical strategies that not only impose the increase of construction cost on employers but also the emission of greenhouse gases in the global environment. Regarding the importance of the role of architects, if the initial decisions in the design process are made based on environmental issues and climatic approach, a considerable saving on cost and energy consumption can be achieved. In the meanwhile, passive systems are the most efficient and clean ways to meet the thermal needs of a building by means of utilizing renewable energy resources such as solar energy, wind power, and so on. In this type of system, fossil fuels and mechanical powers are rarely used. Among the mentioned methods, the element of shading device is one of the most effective solutions that has been widely used in traditional Iranian architecture. This solution has a high potential to be implemented in contemporary architecture as well. Measurements and simulation studies have shown that balcony form and solar protection can significantly affect the thermal comfort of occupants on the balcony as well as in the adjacent room. In this research, one of the existing buildings equipped with a glasscovered balcony was selected as a case study and experimental measurements were taken by two data loggers located in the balcony and adjoining room in order to record the temperature fluctuation. The simulation process was validated by comparing the experimental results. The base case building was modeled in Openstudio software (2.6.0) and Energyplus 8.9 and was then utilized for annual energy simulation. The depth of semi-open space, the window area of the adjoining wall, and its thermal conductivity coefficient in the two types of balconies and porches were considered as the variables. The effect of shading strategies such as movable louver and glass cover on thermal performance was comparatively investigated. The simulation results indicated that the use of an open-angle louver as well as a movable glass partition in summer and winter respectively would enhance the thermal performance of the room adjacent to semi-open space. Regarding under-construction buildings, the effect of using attached shading devices on thermal performance on cold days of a year increases based on the depth of the semi-open space along with window to wall ratio. Although the reduction of the thermal conductivity coefficient of window would make the attached glass partition more effective in the winter, the negative effect has to be considered in the summer. Based on the research findings, this paper concluded in determining a design guideline for the application of a movable attached shading device of semi-open spaces in residential buildings in Tehran metropolitan city.