Heat waves are getting more and more common with climate change. A new wearable device could provide cooling relief to both people and the planet. The skin patch can cool down its wearer without using any energy.
The flexible stretchable device, reported in the Proceedings of the National Academy of Sciences, reflects sunlight away from the body to keep it from absorbing heat. It also allows the body to dissipate heat. This allows it to bring down the wearer’s skin temperature by about 6°C during daytime hours.
Plus, the device is breathable and waterproof. It’s developers at the University of Missouri hope to incorporate the material into smart cooling fabrics that could make people more comfortable and reduce heat strokes. “That would allow for the device’s cooling capabilities to be delivered across the whole body,” says Says Zheng Yan, an assistant professor in the College of Engineering at the university.
And that could, perhaps, make a dent in the carbon emissions from air-conditioning. Air-conditioners are energy hogs. Cooling consumes about 10 percent of electricity used worldwide, according to the International Energy Agency. And energy demand for air-conditioning is expected to triple by 2050.
Having a personal wearable air-conditioning device could make people more comfortable, “help reduce electricity usage and also help with global warming,” Yan says.
He and his colleagues made the device with a porous rubbery material that is easy and cheap to make on a large scale. It is flexible and riddled with tiny microscopic pores of different sizes ranging from 0.2 to 7 micrometers. These pores can scatter sunlight but are too small to scatter and reflect the infrared heat waves emitted by the body. So sunlight bounces off the patch while body heat passes through.
Source: Yadong Xu et al. Multiscale porous elastomer substrates for multifunctional on-skin electronics with passive-cooling capabilities. PNAS, 2020.