Exploring the impacts of spatial morphology of underground shopping mall atriums on natural lighting performance

The natural lighting environment in the atrium space of an underground shopping street directly determines the spatial quality of the building. It has a significant impact on the quality of the indoor light environment, people’s mental experience, and the energy consumption of the building. Based on field research, this study combined Radiance and Rhino 7 software to construct realistic scene simulation models of the different shapes for each atrium’s underground shopping street. Daylight factor (DF) and useful daylight illuminance (UDI) were utilized as the evaluation metrics for assessing the natural lighting efficacy of the atriums. Simulation data were further processed and quantitatively analyzed with line charts and quadratic curve fitting methods. The results demonstrate that the DF of an atrium space in underground shopping streets declines rapidly as the height/width ratio (H/W) increases, followed by a gradual weakening trend. Meanwhile, as the aspect ratio (L/W) increases, the peak value of the DF gradually increases. The UDI of the atrium space in an underground shopping street will usually rise first and then fall as the height/width ratio (H/W) increases. Meanwhile, as the aspect ratio (L/W) increases, the UDI peak value gradually decreases. The experiment confirms that DF and UDI atrium space can be effectively improved by adjusting different combinations of the height/width ratio (H/W), aspect ratio (L/W), and lighting glass inclination angle. By doing so, this research provides architects with a theoretical foundation for the spatial morphology design of an atrium.