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

To maintain comfortable indoor conditions, buildings consume similar to 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 similar to 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.

Automated summary

Buildings consume approximately 40% of the world's energy in order to maintain comfortable indoor conditions. The least efficient part of a building's envelope in terms of isolating the interior from outdoor temperatures is the windows and skylights. However, researchers have developed highly transparent cellulose aerogels that have better light transmission, lower haze, and lower thermal conductivity than glass. These lightweight materials can be used to improve energy efficiency in insulating glass units, skylights, daylighting, and facade glazing, potentially enhancing the role of glazing in building envelopes.