While our focus here at CleanTechnica is often confined to electric vehicles and renewable energy, there are lots of other pieces to the carbon reduction puzzle. One of those pieces is better insulation for buildings that does a better job of lowering heating and cooling loads while being biodegradable when the useful life of those buildings is over.
Researchers at the University of Maryland devote a lot of time to finding new uses for wood. Two years ago, they found a way to make it transparent so it could be used as a substitute for glass. Building on that research, they now claim to have found a way to strip away two of its primary components — lignin, which makes wood brown and rigid, and hemicellulose.
The researchers call the result “nanowood” and say it costs less and has insulating qualities that are superior to most of the fiberglass and styrofoam insulation materials commonly used in building construction today. It is also stronger than any other insulation products and will not irritate the lungs of installers the way that fiberglass insulation does.
“This can insulate better than most other current thermal insulators, including Styrofoam,” Tian Li, one of the researchers tells Engadget. “It is extremely promising to be used as energy efficient building materials.” The entire report is available online at Science Advances. Or you can read more without the technical jargon below.
After the lignin and hemicellulose are removed, the microchannels that allow sap to travel from the roots to the leaves of trees remain. These act as tiny air-filled insulating barriers. While they can conduct heat longitudinally, they cannot do so laterally, which gives the nanowood its excellent insulating properties. Once the lignin is removed, the original wood turns pure white.
“My research program experiments with nature’s nanotechnology that we see in wood,” says associate professor Liangbing Hu, who is the leader of the project. “We are reinventing ways to use wood that could be useful in constructing energy efficient and environmentally friendly homes.” The cost of nanowood on a commercial scale is given as $7.44 per square meter. That’s about $0.75 per square foot.
When reduced in thickness to a few millimeters, the material can be rolled up or shaped to conform to pipes and other non-rectilinear shapes. It is a better insulator than styrofoam or closed cell aerogels. “When exposed to the [electromagnetic] spectrum, silica aerogel absorbs ~20% and transmits ~60% of the radiative heat,” according to the Los Angeles Times. “In comparison, ~95% of the radiative energy was reflected, whereas only ~2% was found absorbed by the nanowood.”
Stronger, better insulator, less costly, and biodegradable. That’s an impressive list of advantages. Nanowood could be the breakthrough that permits an important reduction in the carbon footprint of homes and buildings.