Dynamic glazing for a sustainable building future: An in-situ performance evaluation of electrochromic windows in cooling operation

초록

Conventional static glazing passively controls solar radiation, leading to limitations in managing thermal loads and comfort, particularly in commercial buildings with high window-wall ratios. While electrochromic (EC) windows offer a promising dynamic solution, the empirical validation of thermal response and energy performance is necessary in a large-scale context. This research aims to assess the performance of EC glazing against conventional Low-e (LE) systems and establish the adaptive control strategy for energy savings and thermal comfort. Experiments were conducted on two identical, full-scale test beds (WWR >70%) over varying weather conditions in 15 days. The EC test bed's cooling setpoint was systematically adjusted from 24 degrees C to 26 degrees C to evaluate the benefits of 4-stage dynamic tint control, while the LE test bed maintained statically at 24 degrees C as a reference. Performance was evaluated by measuring cooling energy consumption and PMV/PPD indices. The EC window effectively prevented overheating and maintained acceptable thermal comfort across all adjusted setpoints, unlike the LE test bed, which experienced prolonged discomfort PMV > +0.5) under high solar irradiation. The EC window achieved a 16 -31% reduction in daily cooling energy at the same setpoint as the reference. The synergistic effect of dynamic tint control and the adaptive setpoints allowed the EC system to maintain comfort while achieving a significant cooling energy reduction of up to 60% compared to the reference condition. This demonstrates that dynamically controlled EC windows are a highly viable solution for improving the performance of commercial buildings with large fenestration areas.

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