A new study from North America indicates transparent wood beats traditional glass across a number of key performance metrics, paving the way for windows that are more energy efficient while providing softer, more uniform light.
Earlier this year, researchers from Sweden's Royal Institute of Technology announced the development of an "optically transparent wood" that lends itself to mass production, and could serve as a viable substitute for glass as a building material in windows and solar panels.
The Swedish researchers created the product by using a chemical process to extract lignin from natural wood, rendering it white in colour. A polymer was then added to the white porous veneer substrate to increase the material's optical transparency.
Researchers from the University of Maryland have now demonstrated that transparent wood surpasses traditional silicate glasses in a number of key performance areas, paving the way for windows that are more energy efficient and provide a softer and more uniform source of external lighting.
The study led by Tian Li, a postdoctoral researcher at the University of Maryland, found that transparent wood achieves better thermal insulation than glass, which can increase the energy efficiency of buildings where it's installed by reducing heat loss or ingress.
Transparent wood achieves this higher level of insulation while also permitting the entry of nearly as much light as traditional glass.
"The channels in the wood transmit light with wavelengths around the range of the wavelengths of visible light, but...it blocks the wavelengths that carry mostly heat," the researcher said.
While transparent wood approaches traditional glass in terms of transparency, the cell structure of the wood also produces a haze effect that softens any light that passing through it, making it more uniform and less jarring to the eye.
"This means your cat would not have to get out of its nice patch of sunlight every few minutes and move over," said Li. "The sunlight would stay in the same place. Also, the room would be more equally lighted at all times."
This haze effect makes transparent wood an excellent choice for solar panels, as it keeps light trapped within the cells for longer.
Another key advantage of transparent wood is its greater resilience. While traditional glass is brittle and high susceptible to breakage, the cell structure of transparent wood makes it largely resistant to shattering.