Arranging Courtyards in Urban Blocks to Reduce Energy Consumption (Case Study: Tehran Dwellings)

Now a day, climate change and environmental crisis as a global threats have negative effects on all living creatures. These phenomena have been happened because of consumption of non-renewable energy sources such as oil, gas, and coal since the last century. Due to recent obligations to preserve these sources and environment, it is necessary to reduce the consumption of these sources. The residential sector energy consumption accounts for 31% of the energy globally used. This fact, hence, makes it inevitable to further study the thermal performance of residential buildings. Therefore, adjusting the climate of the building surroundings would affect buildings thermal performance. Creating the apt micro-climate around buildings will contribute to the improvement of the building thermal performance. In Iran’s traditional buildings, the central courtyard has always been one of the most effective climate solutions to decrease the temperature in hot- arid regions. Along with an increase in shading by trees and building walls, the building would be protected from direct sunshine and thus, thermal conditions on hot days would balance. It is noteworthy that this shading should not block the sun in cold seasons. In this regard, the aim of the present study is to make alterations in locating the building on the land, so that to create three and four-sided courtyards in urban blocks. Therefore, we could benefit the micro-climate performance in order to decrease energy consumption in these buildings. There has been widespread research about this in different cities of Iran. Despite the necessity to cut down the energy consumption of the residential sector in a metropolis like Tehran, few of these studies have been conducted in this city. Consequently, the case studies of the current research, are residential blocks of apartments in Tehran. Due to different climates in Tehran, central and southern areas were chosen as thesis climate background, because these areas are classified as hot- arid regions. The research method consists of simulation, empirical methods, and logical reasoning. In the beginning, Tehran 7th urban zone was chosen with GIS assistance and calculations were done. Then, thermal performance of the proposed models and the effect of the courtyard on sun energy absorption, access to daylight and wind, were studied by using DesignBuilder software. The results were then compared to the reference model. The results show that four-sided courtyard in Tehran would significantly decrease building cooling load in summer which is about 18.35 kWh/m2. In winter, however, significant impact on the heat load is absent. Field measurements in Memar Bashi Seminary in Tehran, also showed that the temperature in the courtyard is considerably less than that of the outside area. This difference would reach 5 degrees centigrade at the hottest hours. The temperature inside the building is also 1 to 2 degrees centigrade less than that of the courtyard. On the other hand, the graphs obtained from simulations and field measurements also presented a similar pattern. Thus, the results of filed measurements confirmed simulations performed in DesignBuilder software.