Daylight Illuminance in Classrooms Adjacent to Covered and Uncovered Courtyards Under The Clear Sky of Najran City, Saudi Arabia

Daylight penetrating the classrooms makes students efficient, improves overall health and increases energy efficiency. In the hot regions, the concept of courtyards in buildings is deeply linked to the architecture as a sustainable solution to daylight indoors without negatively affecting the building cooling loads in the summer. Najran University has existing courtyards in college buildings. Recently, the university covered the courtyards using PVC canvas. This study aims to investigate and compare the daylight illuminance in classrooms adjacent to covered and uncovered courtyards. A case study of four classrooms in the College of Engineering was investigated under the clear sky of Najran City. Results showed that the daylight illuminance in the classrooms adjacent to the uncovered courtyard was low with a maximum of 100 lux close to the windows when outdoor illuminance was 110 Klux. However, the indoor daylight illuminance in the classrooms adjacent to the a covered courtyard was 18, 10 and 7 lux, with 1, 3 and 5 m distance from the window, respectively. These classrooms depend mainly on electrical lighting