Synergistic modulation of solar and thermal radiation in dynamic energy-efficient windows

Current technologies about the dynamic window in buildings, vehicles, and greenhouses primarily focus on solar radiation modulation for interior lighting, heating and cooling regulation. Mid-infrared thermal radiation of windows, as another important factor for interior thermal load, can be dynamically optimized to further improve energy efficiency. However, it is challenging to achieve synergistic solar and thermal radiation modulation of a window for optimal energy efficiency management. Herein, based on the estimation of the energy-saving potential of a midrise building by controlling the window emissivity, we propose an energy-efficient dynamic window that can synergistically modulate solar and thermal radiation. The prototype of such windows with sequence photonic structures could perform the function of synergistic multiband modulation by loading mechanical strain, and achieve a broad modulation ranges up to 55% in solar transmittance and 25% in mid-infrared thermal emittance. The dynamic window can regulate the steady-state interior temperature of a chamber up to ~4 °C in real-time testing, which could potentially provide annual energy-saving from ~45.5 to ~166.5 MJ m−2 for a typical midrise building located in 11 cities around the world. The intelligent dynamic window system with fast response to the changing weather can further improve home convenience, comfort and artistry and realize an energy-saving residential setting.