The evolution of green energy technology: Developing three-dimensional smart energy devices with radiant cooling and solar absorption

Heating and cooling account for approximately 50% of the global energy consumption, contributing significantly to environmental problems such as global warming and air pollution. In response, solar absorption and radiative cooling devices, which harness the sun and outdoor air as heat and cold sources, are gaining attention as eco-friendly and sustainable solutions. While various devices have been developed, many are limited in function, focusing 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 in a single device. The device operates on a unique mechanism: when the 3D structure opens through a mechanical peeling process, the lower layer -- made of silicone elastomer and silver -- is exposed to generate radiative cooling. When the structure closes, the surface coated with black paint absorbs solar heat, thus producing heating.

The team tested the device on multiple substrates, including skin, glass, steel, aluminum, copper, and polyimide, and demonstrated that adjusting the angle of the 3D structure enabled control over its heating and cooling performance. This ability to modulate thermal properties offers an efficient 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 settings 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 Materials, where they were featured as the cover article.