By Copyright Canva | Qingchen Shen
Researchers in the UK have developed a flexible coating that could help keep buildings cool and reduce their need for air conditioning. Made from a material derived from wood, this film could help fight against urban heat in an ecological, inexpensive and aesthetic way.
Researchers in the UK have developed a flexible coating that could help keep buildings cool and reduce their need for air conditioning. Made from a material derived from wood, this film could help fight against urban heat in an ecological, inexpensive and aesthetic way.
According to figures from the International Energy Agency, air conditioning alone accounts for 10% of the world's electricity consumption. In addition to being energy intensive, these cooling systems release hot air, ultimately contributing to the prevailing heat, especially in cities. However, researchers from the University of Cambridge have found a more ecological solution to keeping cool in hot weather.
They have developed a film for covering buildings and even cars that cools in the sun. This coating is entirely flexible and has the potential to help combat urban heat. It is made from several layers of cellulose, a fiber derived from wood. This polymer of plant origin is a material found in abundance on Earth and is an interesting component for several reasons. In addition to being natural and non-polluting, this film also promises to be inexpensive.
While cool roof techniques have previously involved painting roofs white to cool housing, the Cambridge researchers have managed to add color to their film, while maintaining its cooling properties. To embellish the exterior of buildings, Silvia Vignolini and her colleagues combined the iridescent property of cellulose nanocrystals with the reflective property of ethyl cellulose. Depending on the arrangement of the nanocrystals, the film can take on different shades. "Instead of using dye, the team turned to structural color, the same phenomenon that makes soap bubbles or beetle shells appear iridescent. Light hits tiny structures on the surface and bounces around, reflecting different wavelengths from different angles to create shimmering colors," explains Fast Company.
One square meter of the film can generate over 120 watts of cooling power, as much as some air conditioners. In a previous study, the researchers demonstrated that the material could be 4°C cooler than the ambient air during the day.
The scientists now hope to test the film on real buildings to evaluate its effectiveness on a larger scale. They also plan to subject their innovation to different weather conditions to test its durability over time.
