Optimization of the building orientation to receive solar radiation in hot-aridclimate (Case Studies: Isfahan, Semnan, Kerman and Yazd cities)

Due to the special geographic conditions and hot and dry climate of the central plateau of Iran, the design and construction of climate-friendly buildings and urban spaces in these regions, requires receiving minimum energy in hot months through appropriate orientation, decreasing the area of surfaces facing radiation and maximizing the amount of shading on exterior surfaces. The aim of this research is to determine the optimal building orientations in   hot-arid climate of the region through surveying the amount of direct radiation energy received by vertical surfaces of buildings in Isfahan, Semnan, Kerman and Yazd cities.At first, the amount of received radiation energy was calculated in theoretical and real way ,by using the “Law of Cosines” computational method. Then based on the minimum temperature of thermal comfort, the amount of energy received by the vertical surfaces was calculated and processed in 24 different geographical directions, separately for cold and hot periods of the year. Finally, based on the minimum energy received during the hot period of the year, the most suitable orientations of vertical surfaces of buildings for one, two and four-sided buildings were determined in studied cities. The research findings show that the best orientation of vertical surfaces for one-sided buildings in Isfahan, Semnan, Kerman and Yazd is 180 degrees South and after that, is 165 degrees SE. Also, the best orientation of vertical surfaces for two-sided buildings in studied cities is (180, 0) and for four-sided buildings is (180, 0, 90, -90) degrees.