Optimization of form, aspect ratio and orientation of building based on solar radiation and wind direction (Case studies: Tabriz, Yazd and Bandar Abbas cities)

The renewable energies (such as solar energy), could be provided through designing architectural and urban spaces compatible with the climate and the ecosystem of the region, taking into consideration the architectural features of the building such as its form, dimensions and orientation. The purpose of this research was to determine the most suitable form, aspect ratio and orientation of the building for receiving optimal solar radiation and The prevailing wind direction in Tabriz, Yazd and Bandar Abbas cities. In this research, six common geometric forms, including square, rectangular (EW and NS orientation), hexagonal, octagonal, hexadecagon, and triacontadigon (circle) with an equal area and elevation facing the South, were studied and among them, the form of rectangle, with aspect ratios of 1:1.2, 1:1.4, 1:1.6, 1:1.8 and 1:2, in the directions 120, 135, 150, 165 and 180 degrees SE, and SW has been studied. The amount of received radiation energy on vertical surfaces has been calculated and processed through theoretical and real calculation, using the “Law of Cosines” computational method for different months and in 32 geographic directions , in terms of the cold and hot periods of the year. The results of the research show that the best form of building in all studied cities is rectangular with East-West orientation and the next form is the square. The most suitable aspect ratio for the rectangular form with the East-West orientation is 1:1.2 in Tabriz city and 1:1.6 in Yazd and Bandar Abbas cities. Suitable orientation of the building based on solar radiation and The prevailing wind direction in Tabriz city is 165 degree SE and in Yazd and Bandar Abbas cities is 180 degree south.