Photochromic Thermoelectric Smart Window for Season-Adaptive Solar Heat and Daylight Management

Photochromic smart windows have drawn increasing attention as an approach to improve building energy efficiency and enhance indoor daylight comfort. However, existing photochromic smart windows still block sunlight from entering the room on sunny winter days, causing additional energy consumption for heating. Herein, a dual-mode smart window is designed with decoupled photo and thermal functions by combining colorless Fe-doped WO₃ photochromic film with window rotation. Based on this, selective heating and cooling of the room between winter and summer is achieved while maintaining the daylight comfort benefits during all seasons. As a proof of concept, the smart window reduces the temperature of a model house by up to 7.9 °C in summer mode, while in winter mode the temperature is only reduced by 0.7 °C. The proposed seasonally adaptive dual-mode smart window obtains by window rotation overcomes the limitations of conventional photochromic smart windows, which not only achieves better energy efficiency but also retains improved daylight comfort. Furthermore, it demonstrates that the heat absorbed by the smart window can be harnessed to produce electricity through the integration of thermoelectric modules within the glazing, which enhances its impact on reducing energy consumption.