Active smart switchable glazing for smart city: A review

Globally building sector consumes a significant amount of fossil fuel-generated grid energy which emits a considerable level of carbon emissions. These scenarios can be an obstacle to sustainable or smart city developments. In a building which consists of various components, windows are the most influential to contribute to this energy consumption. To abate the excessive amount of building energy consumption, an alternative glazing system is paramount. Among the other available energy-efficient glazing, an active smart switchable is promising as it can be altered based on occupant choice. In this work, four active smart switchable glazings have been studied (electrochromic, suspended particle device, liquid crystal and gasochromic) based on their operating principle, glazing factors and energetic application. It is evident that EC has more material aspect investigation and overall energetic application for PLDC, SPD and EC needs more study. Gasochromic which can be a potential in future is not explored in higher order. However, these types of windows integration in buildings and how they will have an impact on urban heat islands, part of smart buildings, smart cities and digital twins have also been discussed. •Four active smart windows were reviewed in this work.•Gasochromic can be a potential option as hydrogen economy is getting priority.•Long term outdoor investigation of active smart glazing is essential.