Highly transparent silanized cellulose aerogels for boosting energy efficiency of glazing in buildings

TLDR

Buildings consume about 40 % of global energy, and windows and skylights are the least efficient envelope components, making simultaneous high transparency and thermal insulation a major challenge. This work aims to create highly transparent cellulose aerogels that can improve glazing energy performance. The aerogels are fabricated by colloidal self‑assembly of cellulose and roll‑to‑roll compatible processing. The resulting aerogels transmit 97–99 % of visible light, exhibit ~1 % haze, have thermal conductivity lower than still air, and when incorporated into multi‑pane insulating glass units or retrofitted windows, they boost energy efficiency and enable advanced glazing solutions.

Abstract

Abstract To maintain comfortable indoor conditions, buildings consume ~40% of the energy generated globally. In terms of passively isolating building interiors from cold or hot outdoors, windows and skylights are the least-efficient parts of the building envelope because achieving simultaneously high transparency and thermal insulation of glazing remains a challenge. Here we describe highly transparent aerogels fabricated from cellulose, an Earth-abundant biopolymer, by utilizing approaches such as colloidal self assembly and procedures compatible with roll-to-roll processing. The aerogels have visible-range light transmission of 97–99% (better than glass), haze of ~1% and thermal conductivity lower than that of still air. These lightweight materials can be used as panes inside multi-pane insulating glass units and to retrofit existing windows. We demonstrate how aerogels boost energy efficiency and may enable advanced technical solutions for insulating glass units, skylights, daylighting and facade glazing, potentially increasing the role of glazing in building envelopes.