Medical News
Technology
23 May 2019
Wood you like to live here?David M Schrader/Getty
By Yvaine YeHouses made of high-tech wood could help us stay cool and also reduce carbon emissions by cutting energy used on air conditioning.
Liangbing Hu at the University of Maryland and his colleagues created the material by removing the lignin—a component of the cell walls in trees—from natural wood using hydrogen peroxide.
The remaining wood is mostly made of cellulose, another component of plant cell wall. Cellulose reflects visible light and only absorbs very low levels of near-infrared light. This means the cooling wood reflects most of the components of sunlight right back to the environment. As a result, a building made from this material would transmit barely any heat indoors.
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The team also found that the material can absorb heat produced indoors, which is emitted at a different wavelength range to sunlight. During cooler nights, the wood helps release the heat outside, making it useful day and night.
Hu says the cooling wood is very dense and has a tensile strength of around 404 megapascals, making it 8.7 times stronger than natural wood and comparable to metal structure materials including steel.
To investigate how much energy the wood could save, the team simulated replacing the exterior walls and the roofs of some apartment buildings in 16 US states, representing a variety of climate conditions. They found the wood could reduce cooling energy requirements by an average of 20 to 35 per cent.
However, because cooling wood prevents heat from the sun from getting indoors, it will result in additional heating costs in winter. Therefore, Hu says the material is best suited for warm areas with long summers and short winters, such as Arizona and Hawaii.
Journal reference: Science, DOI: 10.1126/science.aau9101
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