Heating and cooling account for approximately 50% of global energy consumption, which greatly contributes to environmental problems such as global warming and air pollution. In response, solar absorption and radiant cooling devices, which utilize the sun and outdoor air as heating and cooling sources, are gaining attention as environmentally friendly and sustainable solutions. Although various devices have been developed, many are limited in function and focus solely on heating or cooling, and large-scale systems lack adjustability.

To address these limitations, Prof. Kim’s team created a “3D Smart Energy Device” that integrates reversible heating and cooling functions into a single device. The device works on a unique mechanism: when the 3D structure is opened through a mechanical scaling process, the bottom layer – made of silicone elastomer and silver – is exposed to generate radiant cooling. When the structure is closed, the surface coated with black paint absorbs solar heat and thus produces heat.

The team tested the device on multiple substrates, including skin, glass, steel, aluminum, copper and polyimide, and showed that adjusting the angle of the 3D structure allowed control over its heating and cooling performance. This ability to modulate thermal properties offers an effective and promising solution for reducing energy consumption in temperature-controlled buildings and electronic devices at both macro and micro scales.

“We are honored to have our research selected for the cover article of such a prestigious journal,” said Professor Bonghoon Kim. “We aim to ensure that these findings are applied in industrial and building environments to help reduce energy consumption.”

This research was supported by the “Global Bioconvergence Interfacing Leading Research Center (ERC)” and the “Nano and Materials Technology Development Project” of the National Research Foundation of Korea. The results were published in Advanced materialwhere they were featured as the cover story.