Innovative and Energy Efficient Smart Window Based on Nanomaterial Technologies

Abstract

Strategies for incorporating energy-efficiency requirements into building standards have been implemented by governments in developed countries in order to introduce the concept of green nanotechnology. Substituting regular glass windows in residential/commercial buildings with smart windows is the objective. This paper describes the development of innovative nanomaterial based membranes/coatings for smart windows that would work as electric dimming glass. Currently, curtains and blinds function to block sun light; eliminating such elements is of importance due to its limited functionality (e.g. blocking UV prevents sun light illumination), health (e.g. dust and germ collection especially in hospitals), disposal/recycling issues, cost, and maintenance. The proposed smart window is expected to block harmful UV light and provide a controlled privacy. Electrochromic smart windows are already in use and are able to vary their throughput of visible light and solar energy by application of electrical voltage and are able to provide energy efficiency and indoor comfort in buildings. These smart windows comprises of electrochromic materials such as LixWO2.89 and HxNiO2 as cathodic and anodic oxide films, respectively, and other complex polymers, which are complicated to create, expensive and some are hazardous in nature. Nanocellulose (achieved from wood/pulp product) is already being used in flexible electronics, so nanomaterial membrane for smart window is a probable alternative. This paper presents an innovative technology for smart-windows, utilizing nanocellulose fiber (abundantly available) doped with conductive nanoparticles (work as dimming glass on voltage application), mixed with minute amount of electrochromic material form thin film membranes.