Research team develops wood-based foam to keep buildings cooler

Many people try to beat the heat during the summer. Air conditioners can be expensive and wasteful. A lightweight foam made from wood-based cellulose nanocrystals that reflects sunlight and emits absorbed heat has been designed by researchers. The material could reduce cooling energy needs by more than a third.

Scientists have developed cooling materials, but they have disadvantages. Some materials let a lot of heat through to buildings under the sun. In hot, humid or cloudy weather, other materials that reflect sunlight don't work well. Yu Fu, Kai Zhang and colleagues wanted to develop a robust material that could reflect sunlight, release heat and keep heat out.

The material was frozen and dried under a vacuum after being connected with a Silane bridge. The process vertically aligned thecrystals, making a white, lightweight foam, which reflected 98% of visible light and emitted 98% of absorbed radiation.

The temperature inside the box was 16 degrees cooler than the temperature outside when it was placed over. The inside of the box was 13 degrees cooler when the air was humid. The cooling ability of the foam decreased as it was compressed.

The team calculated that placing foam on the roof and exterior walls of a building could reduce its cooling energy needs by an average of 34%. The technology could be applied in a wide range of environments because the wood-based foam can be changed depending on weather conditions.

More information: Chenyang Cai et al, Dynamically Tunable All-Weather Daytime Cellulose Aerogel Radiative Supercooler for Energy-Saving Building, Nano Letters (2022). DOI: 10.1021/acs.nanolett.2c00844 Journal information: Nano Letters Citation: Research team develops wood-based foam to keep buildings cooler (2022, May 18) retrieved 18 May 2022 from https://phys.org/news/2022-05-team-wood-based-foam-cooler.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.