New research shows that you might be able to cool your home with ‘super-wood.’ By stripping the wood of its lignin before densification, it actually allows the densified wood to cool in bright sunlight.
By doing this, buildings that are constructed using this material would have a smaller carbon footprint and limited need for air conditioning.
This wood is the first material of its kind to inherently cool down in bright sunlight. Other experiments have involved creating paints and films that would achieve a similar, simpler affect.
But thanks to the collaboration between the University of Colorado, Boulder research team and the University of Maryland, College Park team, their joint efforts have developed this cooling, densified wood. They are the developers of the cooling film and the densified wood, respectively.
To densify the wood, it must first be stripped of its lignin—in wood, the lignin is essentially what allows a tree to stand. It is the formation of the cell walls that provide a tree with rigidity and a longer resistance to rotting.
To do this, one can simply boil it in hydrogen peroxide. Then, it will be able to scatter visible light effectively, as well as be highly emissive in the infrared transparency window. Further, it does not sacrifice structural integrity; it is still about nine times as strong and ten times as tough as natural wood.
This shouldn’t happen, though. When you remove the lignin—the thing that makes wood strong—wouldn’t it just become weak? In fact, when you “press together the cellulose fibres so they form a lot of hydrogen bonds in the dry state, you can maximise their interaction,” says University of Maryland’s Liangbing Hu. So even though stripping wood of its lignin should weaken it, by densifying it and pressing it together, that strength is essentially re-created.
While the cost of materials is still unknown, it is quite a lengthy and time consuming process to create this ‘super-powered’ wood that, simply, defies physics. If you were able to completely cover a building in this material that would simultaneously reflect visible wavelengths but also be emissive in transparency, it would effectively radiate away heat and cool down in sunlight.
This could be a game changer in greener building materials. Would you use this densified wood in any of your building projects?