Using solar screens in school classrooms in hot arid areas: the effect of different perforation on daylighting levels

Hot arid areas are endowed with an abundance of clear skies. Thus, the solar energy available can significantly raise the temperature of interior spaces and also result in an uncomfortable visual environment due to glare and poor uniformity ratios. This paper focuses on a special case of girls’ schools in Saudi Arabia, where the privacy issue is critical due to socio-cultural and religious beliefs. Most windows in girls’ schools are covered by dark opaque film to maintain privacy. This window treatment brings the need for electric lights, which makes schools huge consumers of energy considering the peak time operational hours and the large number of schools. This paper looks at how different perforation rates affect the performance of screens by simulating 10 different ratios from 10% to 90% and a base case without a screen. First, the effect was tested on average illuminance levels, and then on Daylight Availability by using the Daylight Dynamic Performance Metrics approach (DDPM). The results specify the minimum perforation rate to provide the required average illuminance in each orientation and give a tool to decide perforation rates according to the required percentage of daylit area in contexts similar to the studied space