Abstract:The study measured shading coefficients and optical performance of three kinds of rollers, and then the combined cooling and lighting energy consumption and combined energy saving coefficients were obtained. A typical room and window to wall ratios were established to assess the impact of shading devices on the cooling and lighting energy consumption. The results show that the roller with high visible transmittance and a low shading coefficient is more energy saving. When the window to wall ratio equals to 0.3 and 0.5, respectively, the energy saving rate of the roller reaches 66% and 47% correspondingly in comparison with the standard glass. When the window to wall ratio is 0.3 and fluorescent lights are used, the control logic of the roller can save energy by 5.4%. If halogen tungsten lights are used, the control method even can save energy by 20.7%. Based on the simulation and calculation results, when outdoor daylight and thermal environment are taken into consideration, energy saving shading devices are proposed to have high visible transmittance and solar light reflectance.