Researchers have unveiled a groundbreaking process that could one day replace traditional refrigeration systems, which currently rely on environmentally harmful gases.
Modern cooling systems use refrigerants that absorb heat as they turn into gas and release it when they condense back into a liquid. While effective, many of these chemicals, especially hydrofluorocarbons (HFCs), have a high global warming potential (GWP). As part of the Kigali Amendment, countries have pledged to cut HFC production by 80% within the next 25 years, driving the urgent need for cleaner alternatives.
Developed by scientists at Lawrence Berkeley National Laboratory and the University of California, Berkeley, ionocaloric cooling presents a safer and more sustainable option. This technology works by manipulating how materials store and release energy when changing phases, such as from solid to liquid.
In typical cooling processes, melting ice absorbs heat, thereby cooling its surroundings. The ionocaloric process enhances this effect by introducing charged particles (ions), similar to how salt accelerates the melting of ice on winter roads. By adding or moving ions, the melting point of a fluid can be altered, creating a cooling cycle.
The research team demonstrated how applying an electrical current moves ions through a material, shifting its melting point and thereby changing its temperature. In one experiment, they used a salt made of iodine and sodium to melt ethylene carbonate, a compound derived from carbon dioxide and commonly used in lithium-ion batteries. With less than one volt of electricity, they achieved a temperature change of 25°C.
This performance outperforms current caloric cooling methods and offers the potential for a system that could even be carbon negative, as it uses materials derived from captured CO₂.
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.”
Ravi Prasher, another Berkeley Lab engineer involved in the project, added that the next challenge is balancing energy efficiency, GWP, and equipment cost. He remarked, “From the first try, our data looks very promising on all three fronts.”
Researchers around the world are experimenting with different salts and electric field techniques to refine the process. A 2025 follow-up study demonstrated a nitrate-based salt system that could be recycled using electric fields and membranes, a development that could make the technology even more practical for commercial use.
If successful, ionocaloric cooling could revolutionize refrigeration and climate control by eliminating harmful gases, lowering costs, and improving energy efficiency. This principle could also be adapted for heating systems, offering a dual solution for homes and industries in the future.
“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.”
The full research was published in Science.
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