Lightweight switchable smart solutions for energy saving large windows and glass façades

ended

Between 25 and > 60% of total energy transfer through building envelopes is driven by glass based components such as windows, glass facades and glass roofs. In winter, heating energy demand of buildings with high windows-to-wall ratio (WWR) in north- and east direction is up to 35% higher compared to buildings with only small windows. In summer, large windows and glass facades result in high heating of the building interior: cooling energy demand is increased by a factor ≈ 1.5 to 5 when WWR increases from 10% to 90%. Non-residential buildings often make use of large windows or glass facades for building-functional and representative reasons and therefore hardly suffer from increased energy demand. Switch2save targets active management of radiation energy transfer through glass-based building envelopes by integrating transparent energy smart materials with switchable total energy transmission values (g-value). Such materials are electro-chromic (EC) or thermo-chromic (TC) systems. Intelligent switching of those allows significant reduction of both heating energy demand in winter and cooling energy demand in summer. Switch2save’s unique and lightweight combined EC and TC smart insulating glass unit will be a breakthrough in performance (plus 20%); low-cost potential (minus 33% manufacturing cost) and increased design opportunities compared to state-of-the-art smart shading solutions. Switch2save prototypes will be demonstrated in two representative buildings – a hospital in Athens, Greece and an office building in Uppsala, Sweden by replacing > 50 windows and 200 m² glass façade area. Continuous monitoring of energy demand at thermal comfort levels inside the buildings for at least one year before and after TC/EC integration will verify energy saving potential of Switch2save solution. Switch2save increases the market and application potential of energy smart glass in buildings – targeting the whole building glass market of 4.7 billion square meters produced per year.