Electrocaloric device drops temperature 8.9ºC
31st January 2025
USA: Materials scientists at UCLA are said to have developed a compact cooling technology that can pump away heat continuously using layers of flexing thin films.
The prototype design, based on the electrocaloric effect, was found to lower ambient temperatures of its immediate surroundings by 16ºF (8.9ºC) continuously and up to 25ºF (13.6ºC) at the source of the heat after about 30 seconds.
Detailed in a paper published in Science, the approach could be incorporated into wearable cooling technology or portable cooling devices.
“Our long-term goal is to develop this technology for wearable cooling accessories that are comfortable, affordable, reliable and energy-efficient — especially for people who work in very hot environments over long hours,” said principal investigator Qibing Pei, a professor of materials science and engineering at the UCLA Samueli School of Engineering.
The experimental material is composed of a circular stack of six thin polymer films, just under an inch in diameter and one-quarter of an inch thick for the entire stack. Each layer is coated with carbon nanotubes on both sides. Being ferroelectric, the material changes shape when an electric field is applied.
When the device’s electric field is switched on, the stacked layers compress against each other in pairs. When the electricity switches off, the stacked pairs come apart to then press against the other neighbouring layers. As this alternating process repeats itself, the self-regenerative, accordion-like cascading action continually pumps heat away, layer by layer.
“The polymer films use a circuit to shuttle charges between pairs of stacked layers, which makes the flexible cooling device more efficient than air conditioners,” said Hanxiang Wu, one of the study’s co-lead authors and a postdoctoral scholar working in Pei’s lab.
“Because we can use thin flexible films, electrocaloric cooling would be most ideal for next-generation wearables that can keep us cool under strenuous conditions,” Pei said. “It could also be used to cool electronics with flexible components.”
