New Materials Enable Dynamic Building Facades
Recent research in *Nature Sustainability* details new solution-processed electrochromic materials that can be used for dynamic management of solar and radiative heat in building facades. The thin, switchable layers allow for real-time adjustment of solar gain and thermal emission, creating a synergy between the building envelope and internal systems like lighting to improve energy efficiency and occupant comfort.
- Dynamic facades can reduce annual energy consumption for heating, cooling, and lighting by 25-40%, with peak cooling load reductions of up to 45%. For instance, a study at the new Window Systems testbed at Lawrence Berkeley National Laboratory (LBNL) showed daily lighting energy savings of 44-59% compared to a reference window. - The technology directly supports human-centric lighting goals and WELL Building Standard requirements by maximizing natural daylight, which is crucial for regulating circadian rhythms. Unlike traditional shades, electrochromic glass preserves views to the outside, a factor shown to reduce stress and improve occupant well-being. - Integration with building automation systems is a key feature for specifiers; electrochromic glass can be controlled via major protocols like KNX, BACnet, or MODBUS, and increasingly connects to IoT platforms for predictive control based on weather forecasts or building occupancy. While direct DALI control of the glass itself is less common, the facade's state is used as an input for DALI-controlled lighting systems to create a cohesive daylighting strategy. - Key manufacturers that architects and specifiers follow include Saint-Gobain (with their SageGlass product), Halio, and Glassbel. Notable European projects implementing this technology include the Saint-Gobain Tower in Paris, designed by Valode & Pistre, which utilizes dynamic glazing to optimize natural light and thermal comfort. - From a material innovation standpoint, German research from the Fraunhofer Institute is exploring modular facade units that integrate decentralized ventilation and phase change materials (PCMs) to store and release thermal energy, further enhancing energy efficiency. - The visible transmittance (VT) of electrochromic glass can be precisely controlled, often ranging from over 60% in its clear state down to 1% when fully tinted. This wide range is critical for glare control on screens, a key consideration for architects designing modern office environments, while still allowing natural light to enter the space. - While the initial cost is higher than traditional glazing, specifying electrochromic facades can allow for a reduction in the size of HVAC systems, providing an avenue for cost savings in the overall construction budget. Payback periods are most favorable in cooling-dominated climates, with documented savings of 19% on cooling energy in a Singapore-based study. - Regarding sustainability, the focus is on extending the lifespan of buildings through durable and adaptable systems. While complex to recycle due to their layered composition, the core material, glass, is infinitely recyclable. The industry is moving toward circular economy principles by designing for disassembly and maximizing material reuse to reduce waste.
