خودسایه‌اندازی و بهره‌وری انرژی در الگوی معماری سرآمد، مورد مطالعاتی: فرم کلی ساختمان‌های میان‌مرتبه تهران

میزان بالای مصرف انرژی برای سرمایش و گرمایش ساختمان، همواره از دغدغه‌های اساسی معماران در فرآیند طراحی معماری بوده است. مروری بر ادبیات موضوع و پیشینه پژوهش نشان می‌دهد که یکی از این تدابیر مهم و اساسی در تحقق الگوی «معماری سرآمد»، به‌کارگیری مفهوم «خودسایه‌اندازی» در طراحی به معنای استفاده از راهکاری برای ایجاد سایه بر روی سطوح پیرامونی ساختمان است. براساس چارچوب مفهومی طراحی شده، فرم‌های خودسایه‌انداز برای آن‌که بتوانند به‌عنوان فرم بهینه به‌کار گرفته شوند، باید حداکثر انرژی تابشی ممکن را در زمستان و حداقل آن را در تابستان کسب نمایند. از این رو هدف از این پژوهش، تحلیل نقش خودسایه‌اندازی در کاهش مصرف انرژی ساختمان و تحلیل میزان تاثیر به‌کارگیری فرم‌های خودسایه‌انداز در بهبود عملکرد انرژی ساختمان‌های شهر تهران است. براساس روش تحقیق، راهبرد نیمه تجربی، روش توصیفی تحلیلی، تکنیک شبیه‌سازی و تدبیر مقایسه نمونه‌ها برای پژوهش انتخاب شده است. با بهره‌گیری از ابزار یکی از نرم‌افزارهای تجاری موجود، شانزده نمونه از فرم‌های متداول ساختمان‌های میان‌مرتبه موجود در معماری معاصر جهان؛ با هدف دست‌یابی به فرم بهینه ساختمان در اقلیم تهران، مورد ارزیابی قرار گرفت. نمونه‌های اصلی در ماه‌های مختلف سال، از طریق شبیه‌سازی و تحلیل و مقایسه میزان جذب انرژی خورشیدی توسط مدل‌های ساخته شده، به‌صورت خاص مورد بررسی قرار گرفته و سپس شاخص‌های در نظر گرفته شده بر روی مدل‌های مورد نظر ارزیابی شد. دستاوردهای حاصل از مطالعات صورت گرفته نشان‌دهنده آن است که به‌کارگیری شیوه خودسایه‌اندازی و ایجاد سایه در سطوح پیرامونی ساختمان‌ها به‌واسطه کنترل انتقال حرارت به محیط داخلی ساختمان، تاثیر زیادی در بهینه‌سازی مصرف انرژی دارد.

Selfshading and High Performance Architecture, Case Studies: Configuration of Contemporary Buildings of Tehran

High level of energy consumption for heating and cooling in building during different seasons is one of the most important issues that effect the architectural design process. According to formal released statistics by proper channels, in 2014, 28 to 32 percent of the total energy consumed in houses. On the other hand about 25 percent of the carbon dioxide generated in this year, is the result of using fossil fuels in the commercial and residential sectors respectively. Literature review of the paper show that widespread use of electricity as a source of inner light emphasizes on the significance of daylight in building. On the other hand based on architectural design principles, the use of daylight in architecture has always been one of the concerns in architectural design based on psychological prerequisites. Therefore, due to the high level of energy consumption in the building sector in Islamic Republic of Iran, it is important to focus on available potentials in passive energy gain such as better architectural design. The actions in order to improve the quality of building from the standpoint of heat exchange control and how to use sunlight, results in significant saving in the total energy consumption. Literature review shows that light transform into heat because the long wavelength, or infrared, portion of the solar radiation resonates well with molecules in the material, thereby setting them into motion. Gained heat from solar radiation transforms into heat as well as imposes considerable amount of energy for summer cooling. On the other hand, Regular shading devices do not allow direct sunlight to pass the window glazing therefore these kinds of devices may result in increase in winter thermal load as well as increase in energy consumption. Selfshading in architecture design means, using techniques to create shadow on the surfaces of buildings that introduced during period specified and calculate by the designer.This paper is to contribute a procedure for improvement of building form regarding a better selfshading in order to produce a better energy efficient architecture. The paper investigates different strategies for optimization the use of sunlight during the cold and hot seasons. In other words, the main goal of this research is to study different aspects of sunlight and shading, especially thermal aspects of sunlight in building design. The paper estimates the impacts of applying selfshading as an energy efficient approach to improve the energy performance of building. Regarding the research objectives, the most important questions of the research are: 1) How selfshading affects energy consumption in building? 2) What types of buildings regarding to common buildings’ configuration of Tehran show a better performance in energy consumption? Methodology of the paper is based on quasiexperimental research strategies in empirical attitudes. Descriptive analytic research method adopted as inference mechanism, commercially available simulation software adopted as research tool. The most influential tactic in this research is to analyses the role of selfshading in different types of buildings’ configuration regarding to level of energy consumption. Analysis and comparison of solar energy absorption by means of simulated models programmed to estimate optimum characteristics of building configuration. The adopted research methodology proposes usage of the concept of the Solar Collection Envelope (SCE) to analyze efficiency of different kinds of buildings’ configurations. Sustarc as a model for the design of the urban fabric with solar rights considerations adopted to analyze different types of building configurations. Using the SCE nomogram, the designer may determine the orientation and building profile, guarantees that it is selfshaded during a required period and permits insolation in winter. Therefore, the performance based SCE can be used for conceiving new solutions for the building form regarding to daylightophil architecture. To understand the role of selfshading in energy efficient architecture with particular reference to buildings configuration; contemporary buildings of Tehran adopted as case study of the research. In order to investigate the effect of selfshading in reducing the energy consumption of buildings, different building types should be analyzed and simulated to find optimum building types. Based on analysis in contemporary Iranian architecture and typical building form, sixteen common building forms selected by purpose from among Tehran Buildings. The results of simulation and modeling show that the application of selfshading method and shadows at the surrounding buildings by controlling the heat transfer to the indoor has a significant impact on energy efficiency in order to materialize a highperformance architecture. The results emphasized on the importance selfshading in reducing the energy consumption of building especially in cold and hot seasons. The simulation and modeling process shows that selfshading may be adopted as an influential tool to improve the energy performance of building, especially in Tehran as case study of the research. The results pave the way to understand impacts of selfshading on energy efficiency, by comparing the amount of radiant energy in various forms.