Introducing ionocaloric cooling — a groundbreaking method for reducing temperatures that could replace current refrigeration systems with a safer, more environmentally friendly alternative.
How Traditional Refrigeration Systems Work
Conventional refrigeration works by moving heat away from an area using a fluid that absorbs warmth as it evaporates into a gas, then circulates through a closed system and condenses back into a liquid.
While efficient, many of the refrigerants used in this process are harmful to the environment.
There’s more than one way to make a material absorb or release heat energy.
In 2023, scientists from Lawrence Berkeley National Laboratory and the University of California, Berkeley, introduced a new approach that leverages the energy stored or released during a material’s phase change—like when ice melts into water.
How Ions Can Trigger Cooling Without Heat
When ice melts, it absorbs heat from its surroundings, producing a cooling effect. Interestingly, this process can be triggered without raising the temperature by adding charged particles, or ions—a principle seen when salt is used to melt ice on roads.
The ionocaloric cycle applies this same idea, using salts to shift a fluid’s phase and generate cooling.
“The world of refrigerants remains an unresolved challenge,” said mechanical engineer Drew Lilley of Lawrence Berkeley National Laboratory in California.
“To date, no one has created an alternative cooling method that is effective, efficient, safe, and environmentally friendly. We believe the ionocaloric cycle could achieve all of these objectives if developed properly.”
Modeling the Ionocaloric Cycle for Greater Efficiency
The team developed a theoretical model of the ionocaloric cycle, demonstrating its potential to match or even surpass the efficiency of modern refrigerants. By running an electric current through the system, ions are moved within the material, altering its melting point and thereby changing the temperature.
The researchers conducted experiments using a salt composed of iodine and sodium to melt ethylene carbonate—a common organic solvent also found in lithium-ion batteries and derived from carbon dioxide. This feature could make the system not only carbon neutral (GWP zero) but potentially carbon negative.
In their tests, applying less than one volt of electric charge produced a temperature change of 25 degrees Celsius (45 degrees Fahrenheit), surpassing the performance of existing caloric cooling technologies.
Balancing Environmental Impact, Efficiency, and Cost
“We’re aiming to strike a balance among three key factors: the refrigerant’s global warming potential (GWP), its energy efficiency, and the overall cost of the equipment,” explained mechanical engineer Ravi Prasher from Lawrence Berkeley National Laboratory.
“Our initial results look very promising across all three areas.”
Conventional vapor compression refrigeration systems, however, depend on gases with high GWP—such as hydrofluorocarbons (HFCs)—which contribute significantly to environmental harm.
Ionocaloric Cooling and the Global Push to Reduce HFCs
Countries under the Kigali Amendment have committed to reducing HFC use by 80% within 25 years — a target ionocaloric cooling could help achieve.
Researchers are now working to transition the technology from lab experiments to scalable commercial systems that could serve both cooling and heating needs.
Recent studies have shown promising results with nitrate-based salts recycled using electric fields and membranes, confirming what Prasher and his team had envisioned.
“We’ve developed a new thermodynamic cycle that works,” said Prasher. “The next step is testing materials and methods to solve the engineering challenges.”
Read the original article on: Sciencealert
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