A research team led by Prof. LI Bing from the Institute of Metal Research of the Chinese Academy of Sciences, together with collaborators, has overcome a longstanding bottleneck in refrigeration technology. Their findings, published in Nature on January 22, introduce a novel cooling method based on the "dissolution barocaloric effect," which offers a promising zero-carbon alternative to traditional refrigeration.
Modern civilization relies on refrigeration but at a heavy cost. Traditional vapor-compression cooling consumes large quantities of electricity and produces substantial carbon emissions. Although solid-state cooling has long been considered a cleaner alternative, its practical use has been limited by poor heat transfer efficiency.
The researchers found a way to bypass this limitation by combining the benefits of solid coolants with the flow of liquids. While studying the salt ammonium thiocyanate (NH₄SCN), they discovered that the dissolution of the salt in water results in release of massive amounts of heat and then subsequently applying pressure favors the precipitation, which repeat for refrigeration cycles.
Unlike traditional solid-state methods in which heat struggles to move across boundaries, this new "dissolution barocaloric" method integrates the refrigerant and the heat-transfer medium into a single fluid. This design solves the "impossible triangle" of caloric materials by achieving low carbon emissions, high cooling capacity, and high heat transfer efficiency simultaneously.
Experiments demonstrated striking performance. At room temperature, the method achieved a temperature drop of nearly 30 kelvins in just 20 seconds, while at higher temperatures the cooling span reached as high as 54 kelvins, far exceeding that of existing solid-state barocaloric materials. In a designated prototype cooling cycle, the simulations suggest a cooling capacity of 67 joules per gram (J g⁻¹) and an efficiency approaching 77%.
Using in-situ spectroscopic technologies, the researchers further proved that the process is stable, reversible, and responds instantly to pressure changes—key requirements for practical refrigeration systems.
This technology transcends traditional refrigeration principles based on various phase transitions. By turning the "coolant" into a fluid that can be pumped directly through heat exchangers, it paves the way for the commercialization of powerful, zero-emission refrigeration systems for industrial and home use.
In particular, the excellent high-temperature performance makes the technology an ideal candidate for the demanding thermal management requirements of next-generation artificial intelligence computing centers.
