Two Solar Screens Installed on the Exterior of a Window: Energy and Illuminance Studies

Shading a window decrease the cooling load and reduces the mount of the sunlight to an adequate level. Hence, the shading devices, such as solar screens, are becoming an essential component for green buildings. In this research, double solar screens fixed on an external side of a window, and its effect on the heat gain and illuminance is presented. Two perforated screens with circular holes are considered, and the diameter of the circular holes of each screen is different. Two holes’ diameters for the solar screen are considered, 10 and 15 cm. The experimental measurements are conducted in July, where the temperature and solar radiation are extremely high. The temperature and heat flux at the indoor surface of the window, indoor and outdoor air temperatures and solar radiation in the site are measured. The effects of the screen’s holes diameter on the heat flow and illuminance are presented. When the solar screens are installed, the illuminance level in the rooms is decreased and becomes nearly invariant. Therefore, visual comfort is attained. Additionally, the heat flux is decreased by 50%, and decreasing the perforation of the solar screens will additionally decrease the heat flux.