Scientists at the University of Maryland have created a new type of wood that radiates heat into space. The hi-tech wood was found to absorb heat and provide a passive cooling effect to buildings using it. The scientists estimated that the material could drop a structure’s temperature as much as 10°C and reduce cooling costs as much as 60 percent.
Researcher Liangbing Hu and his colleagues created the material from natural wood using a process involving hydrogen peroxide. Soaking basswood in a solution of hydrogen peroxide broke down the lignin in the wood, which acts as a glue holding the cellulose and hemicellulose together. After being broken down, the lignin molecules could be washed away, leaving a white wood that reflected virtually all incoming light.
After the hydrogen peroxide processing, the researchers used a hot press, an industrial vise for making wood composites, to compress the remaining cellulose and hemicellulose components together. The resulting product was found to be eight times the strength of natural wood, comparable to metal building materials like steel.
Houses using the high-tech wood would stay cooler and carbon emissions would be reduced by cutting energy used on air conditioning. Hu says the material is best suited for warm areas with long summers and short winters, such as Arizona and Hawaii. It could also be important in developing countries where air conditioning is less common.
According to the US Department of Energy, heating and cooling systems emit over a half billion tons of carbon dioxide into the atmosphere each year. Households in the desert Southwest of the United States spend about $400 per year to cool their homes, about twice the national average. If this material were applied to the outsides of buildings in the U.S. Southwest and other similarly warm climates, the passive cooling effect could reduce air conditioning costs by as much as $240. A main concern is that the new wood could be expensive, and the potential energy savings may not offset the price.
