The orientation of residential development in Mashhadthat takes account of daylight

Introduction. Due to population growth and urbanisation, energy consumption by urban buildings, especially in developing countries, is increasing dramatically. Limited energy resources and the need to save on consumption necessitate the optimal design in the field of residential development. Building walls are an important boundary between indoor and outdoor spaces, since daylight has a direct impact on energy consumption in buildings. The optimal use of daylight in living spaces reduces energy consumption dramatically. In this regard, the proper orientation of residential buildings is an effective method of energy consumption optimisation. If the layout of an urban development fits the climate of a region, residential buildings are constructed with account taken of the optimal orientation to daylighting. Materials and methods. The aim of this study is the optimal orientation of a part of residential development in Mashhad. To achieve the goal of the study, comprehensive studies of the city of Mashhad and its environs were conducted and Mashhad climate data were collected. Hence, daylight scattering was analysed for a given area with regard to the optimal angle of orientation to daylighting. Daylight was analysed in the two modes, including the present-day layout and the angular position (the north side), that were compared later. The study area has the angle of 20 degrees from the north to the west. All analyses and simulations were performed on the longest (June 22) and shortest (December 22) days of the year using parametric software programmes Grasshopper and Ladybug. Results. A comparative analysis of the two modes shows that the study area, located in the north, receives more daylight, regardless of the angle of rotation. Mashhad summers are hot and dry, and winters are cold and humid; a lot of light can penetrate into buildings during the hot season. In winter, overshadowing by buildings does not allow enough daylight due to the unfavourable location of the residential development. According to the standard, the optimal rotation angle of buildings in Mashhad varies from 5 degrees northeast to 20 degrees northwest. Conclusions. The results show that the optimal daylight orientation in Mashhad is 20 degrees southeast. This value is in the standard range for the residential orientation, and the amount of light, received in summer and winter seasons, is proportional to the needs of indoor space users; natural lighting makes residential spaces more comfortable and reduces energy consumption.