Heating and cooling systems are some of the biggest consumers of energy, so finding ways to passively cool buildings and electronics could be a huge saver of money and the environment. A new photonic film could be just the ticket, made with a micro-structure inspired by a beetle that likes it hot.
The focus of the study was a hardy little bug called Neocerambyx Gigas. This species of longhorn beetle is commonly found in Thailand and Indonesia, chilling out around active volcanoes where summertime temperatures soar above 40 °C (104 °F) on the regular, and the ground can get as hot as 70 °C (158 °F).
So just how do these beetles handle the heat? Finding out was the goal of the new study by researchers at the University of Texas at Austin, Shanghai Jiao Tong University, and KTH Royal Institute of Technology. The team discovered how the beetle’s shell structure helps it cool down, and mimicked it to make a new passive cooling film.
The longhorn beetle, it turns out, has tiny triangular structures on its wings that reflect sunlight, while also allowing its body heat to escape. So, the researchers set out to mimic that structure in a material.
They started with a polymer called polydimethylsiloxane (PDMS), and incorporated ceramic particles into it. The film was then micro-stamped with a triangular pattern similar to that on the beetle’s wings.
In tests, the new film showed promise in passive cooling. When placed in direct sunlight, items beneath the film were as much as 5.1 °C (9.2 °F) cooler than those without it.
The researchers say that this new film could be used as a coating on things like windows, solar panels, cars, fabrics, wearables and electronic devices, to keep them cool without needing to expend any energy.
“Anywhere that needs cooling, this can help,” says Yuebing Zheng, an author of the study. “Refrigerators, air conditioners and other methods consume large amounts of energy, but this is cooling by itself.”
The researchers say that because the materials and processes used to make the film are already widely available, scaling it up for mass production shouldn’t be too challenging. For now, they plan to continue working to optimize the process.
The research was published in the journal Proceedings of the National Academy of Sciences. The team describes the work in the video below.
Source: University of Texas at Austin
