The energy used to remove cooling loads from windows in both residential and commercial buildings totals about 1.4 Quads (quadrillion BTUs/yr), representing a cost to building owners of about $12 billion per year. Significant savings could accrue if a smart window film technology were available, which could reduce these cooling and heating loads. This project will develop a "smart" window film that allows more of the sunlight to penetrate a window when the sun is low in the sky (winter time), and reflects most of the sunlight when the sun is high in the sky (summer time). In Phase I, the feasibility of producing such an angularly selective smart window film was demonstrated by creating a prismatic micro-structured film and combining it with a nano-composite UV curable polymer. In Phase II, the properties of the smart window film will be further refined, optimized, and readied for mass production. Lawerence Berkeley National Laboratory (LBNL) will test the smart window film for its environmental robustness and ease of application to glazing products.
Commercial Applications and Other Benefits as described by the awardee: The smart window film should be immediately applicable to energy conserving window glazings for commercial, industrial, and residential buildings. End-user costs are projected to be $2-3 square foot, using UV cast/cure mass replication production processes. Other applications should include automobiles, military vehicles, aircraft, and the like, for the purpose of reducing their thermal equilibrium temperatures while sitting motionless in the sun, as well as for reduced cooling loads when these vehicles are in motion.
