Light-thermal environment of vertical translucent enclosure structures under solar radiation and method of internal shading adjustment

Building energy consumption accounts for about one-third of global energy consumption, primarily air-conditioning and lighting. The indoor light-thermal environment is closely related to building energy consumption, and internal shading is an effective adjustment method. To understand the method of adjusting indoor light-thermal environment and energy consumption by internal shading and its adjusting effect, this paper establishes the theory of indoor light-thermal environment as well as the simulation and analysis method. A process for analyzing the light-thermal environment of a room with internal shading was established by calculating and fitting the direct solar radiation, scattered radiation, and indoor daylight illuminance. Secondly, with the goal of building energy saving, the “Internal Shading Light-Thermal Ratio” evaluation method is proposed to evaluate the adjustment effect of curtains. The results of the study show that the building energy consumption saved in the room exhibits a sequentially increasing tendency when the surface reflectivity of the curtains is from 10 % to 100 %, respectively. Thin and thick curtains positively contribute to the light-thermal environment improvement by reducing the office's daylight illuminance by about 58.5 % and 90.8 %, respectively, and the indoor solar heat gain by about 42 % and 79.9 %. Meanwhile, the thin curtains had the best adjustment effect at 17:00. In contrast, the rooms with thick curtains had the best adjustment effect at 18:00. In addition, thin curtains meet the requirements for comfort in a light-thermal environment and are more energy-efficient than the room with thick curtains. Compared to the office without curtains, the building energy consumption of the office with thin curtains decreased by 538 Wh, while the office with thick curtains increased by 357 Wh.