An Australia-China collaboration has developed a bioplastic film which can cool buildings by almost 10 degrees during the heat of the day.
Researchers from Zhengzhou University in China and the University of South Australia (UniSA) believe the new sustainable and long-lasting material could reduce building energy consumption by up to 20 percent a year in some of the world’s hottest cities.
UniSA PhD candidate Yangzhe Hou said the cooling metafilm represented a breakthrough in sustainable materials engineering that could help combat rising global temperatures and hotter cities.
“Our metafilm offers an environmentally friendly alternative to air-conditioning, which contributes significantly to carbon emissions,” Mr Hou said.
He said the bioplastic metafilm could be applied to buildings, equipment and other surfaces and passively cool temperatures by as much as 9.2°C during peak sunlight and reflected almost 99 percent of the sun’s rays.
“The material reflects nearly all solar radiation but also allows internal building heat to escape directly into outer space. This enables the building to stay cooler than the surrounding air, even under direct sunlight.”
Mr Hou said the film continued to perform even after prolonged exposure to acidic conditions and ultraviolet light, which were two major barriers that have historically hindered similar biodegradable materials.
Study co-author Xianhu Liu, from Zhengzhou University, said unlike conventional cooling technologies, this metafilm required no electricity or mechanical systems.
“Most existing passive radiative cooling systems rely on petrochemical-based polymers or ceramics that raise environmental concerns,” Dr Liu said.
“By using biodegradable PLA, we are presenting a green alternative that offers high solar reflectance, strong thermal emission, sustainability, and durability.”
Read the full study: A structural bioplastic metafilm for durable passive radiative cooling.
