Silica-based aerogels for building transparent components

Considering the important issues for reaching the target of net-zero emissions, the refurbishment of buildings represents a winning strategy because of the high total energy consumption associated with poor design. New materials, products, and technologies are needed to upgrade building performance and meet environmental targets. A significant work was carried out by the scientific community for the use of aerogel as filler for multi-glazing units to provide good energy-thermal performance and an increasing of daylighting, with consequent reduction in electric consumption. This chapter provides the state-of-the-art aerogel applications for the transparent building envelope, focusing on building-energy-related issues. An overview of both granular and monolithic transparent/translucent silica aerogels is presented and, in particular, the description of the production process is deeply analyzed by considering the different forms. Thereafter, a synthesis of the main physical properties is reported: mechanical, thermal, optical, and acoustic characteristics. Finally, the energy performance of several aerogel solutions incorporated in building glazing systems is described and an overview of the most important recent applications is provided.