In situ testing and model optimization of a smart façade system for zero carbon and enhanced comfort in buildings

Integrating Thermotropic materials into the Parallel Slat-Transparent Insulation Material (TT PS-TIM) double-glazed system enhances indoor daylight comfort and reduces energy consumption through solar regulation and improved thermal resistance. However, the dynamic nature of the system is crucial to determine the daylight and energy performance as the transition between its clear and translucent states results in significant variations in solar transmission/absorption. This study assessed the dynamic optical and thermal performance of the developed system through outdoor experiment. An optimized numerical model for its dynamic state prediction was developed incorporating factors of window surface temperature and slats solar absorption, and validated experimentally, therefore improve the accuracy of dynamic state prediction and further annual building energy consumption. Findings revealed that TT PS-TIM outperformed traditional systems in solar regulation. Meanwhile, the slat-temperature from optimized model showcased a good agreement with experiment data with a deviation of less than 1.3 °C (4.1%). Compared with optimized model, the current simplified model indicated a significantly error for the dynamic state of the TT PS-TIM system, with differences ranging from 23.83% to 64.82% for annual translucent duration, affected by locations, window-to-wall ratios, and slat intervals, leading to increased cooling energy consumption and slight decreases in heating/lighting energy use. • In situ experiments analyzed the performance of complex thermotropic window. • Optimized model for complex thermotropic window developed. • The optimized model's reliability validated through experimental results. • Proposed window annual translucent duration conducted by optimized/current models. • Energy consumption compared between the optimized and current models.