Researchers have discovered a new breakthrough process that could one day replace conventional refrigeration, which currently depends on environmentally damaging gases.
Modern cooling systems rely on refrigerants that absorb heat when they evaporate into a gas and release it when they condense back into a liquid. While effective, many of these chemicals, particularly hydrofluorocarbons (HFCs), have an extremely high global warming potential (GWP). Nations under the Kigali Amendment have pledged to cut HFC production by 80% in the next 25 years, creating an urgent need for cleaner alternatives.
A New Solution
Developed by scientists at Lawrence Berkeley National Laboratory and the University of California, Berkeley, ionocaloric cooling offers a safer and more sustainable option. It works by manipulating how materials store and release energy when changing phases, such as from solid to liquid.
Typically, melting ice absorbs heat, cooling its surroundings. The ionocaloric process accelerates this effect by introducing charged particles (ions), much like how salt melts ice on winter roads. In this system, adding or moving ions changes a fluid’s melting point, creating a cooling cycle.
Drew Lilley, a mechanical engineer at Berkeley Lab said:
The landscape of refrigerants is an unsolved problem. No one has successfully created a solution that’s efficient, safe, and eco-friendly. We think the ionocaloric cycle has the potential to achieve all of that.
How It Works
The team demonstrated how applying an electrical current moves ions through a material, shifting its melting point and thus its temperature. Using a salt composed of iodine and sodium to melt ethylene carbonate, a compound made from carbon dioxide and commonly used in lithium-ion batteries, the experiment achieved a temperature change of 25°C with less than one volt of electricity.
This level of performance not only outpaces existing caloric cooling methods but also hints at a system that could be carbon negative, since it uses materials derived from captured CO₂.
According to Ravi Prasher, another Berkeley Lab engineer involved in the project, the challenge now is balancing three key factors: energy efficiency, GWP, and equipment cost. “From the first try, our data looks very promising on all three fronts,” he noted.
Researchers worldwide are now experimenting with different salts and electric field methods to refine the process. A 2025 follow-up study demonstrated a nitrate-based salt system that could be recycled using electric fields and membranes, an advancement that could make the technology even more practical for commercial use.
The Future of Green Cooling
If successful, ionocaloric cooling could revolutionize climate control and refrigeration by eliminating harmful gases, cutting costs, and improving energy efficiency. The same principle could eventually be adapted for heating systems, providing a two-in-one solution for future homes and industries.
Prasher said:
We’ve created a brand-new thermodynamic framework that combines ideas from multiple scientific fields. Now, it’s about testing materials and refining designs to make this a reality.