A novel sun-shading design for indoor visual comfort and energy saving in typical office space in Shenzhen

Excessive direct sunlight in buildings can cause discomfort glare and overheating, necessitating effective exterior shading systems. This study aims to design an optimal exterior sun-shading system that improves indoor visual comfort (IVC) while reducing annual building energy consumption (BEC) in subtropical climate zones. Previous studies focused on the impact of full shading devices such as louvers on the indoor lighting environment, with fewer studies considering the optimization of energy consumption and the comprehensive evaluation of indoor lighting environment in the design stage using multi-objective optimization based on year-round simulation. Meanwhile, earlier studies mostly considered simple shading forms for single application scenarios, lacking innovation and the ability to adapt to complex situations. Our study aims to propose a complex multiple layered adjustable semi-shading system and evaluate its performance to fill the research gap in this area. Our evaluation method integrates three key performance indicators: Spatial Useful Daylight Illuminance (sUDI), Spatial Daylight Glare Probability (sDGPexceed), and Total Energy Consumption (TEC). We employ Radiance for daylighting simulations, ClimateStudio for glare analysis, EnergyPlus for energy calculations, and multi-objective optimization algorithms to determine optimal designs. We investigated 12 shading configurations with varying numbers of slats (2-5) and rotation angles (- 52.5 degrees, 0 degrees, 76 degrees). Compared to unshaded conditions, the optimum solutions reduced sDGPexceed by 49-53% and decreased total energy consumption by approximately 100 kWh for a typical office space, demonstrating significant improvements in both visual comfort and energy efficiency.