A group of researchers from the U.S. and China have developed a new material they refer to as ‘high-tech wood’ that could be used for building houses which provide adequate cooling while simultaneously cutting down on the energy demands of air conditioning.
The material was achieved by ridding natural wood of lignin (a component of cell walls in wood and bark) by subjecting it to the effects of hydrogen peroxide – a chemical compound used in everything from bleaching agents to rocket propellants.
Since the resulting material is made up of mostly cellulose, structures built using around it would likely transmit almost no heat indoors, owing to the fact that cellulose reflects almost all visible (and absorbs only very low levels of near-infrared) light.
“The energy emitted within the infrared range of the cooling wood overwhelms the amount of solar energy received. We confirmed this cooling effect by real-time temperature measurements of natural and cooling-wood samples, in which the materials were exposed to the sky,” wrote the authors in their paper.
Another benefit of ‘high-tech wood’ is the ability to absorb indoor heat – produced by the human body, as well as different types of equipment – and release it outside, thereby enhancing the overall cooling effect even further.
According to the corresponding author Liangbing Hu from the University of Maryland, the new delignified wood boasts a tensile strength of approximately 404 megapascals, which makes it as many as 8.7 times stronger and 10.1 tougher than its natural counterpart, which is comparable to a variety of metal alloys, such as steel.
Estimates based on the conditions prevailing in 16 U.S. cities have shown that replacing the roofs and exterior walls of at least some of the apartment buildings with delignified wood could result in energy savings “between 20 and 60%, which is most pronounced in hot and dry climates”.
“This multifunctional, scalable cooling-wood material holds promise for future energy-efficient and sustainable building applications, enabling a substantial reduction in carbon emission and energy consumption,” wrote the researchers.
The only drawback of consequence is the aforesaid capacity of the material to radiate indoor heat outside, which means its use should probably be restricted to warm areas with long summers and relatively brief winters.