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Berkeley Lab researchers say ‘ionocaloric cooling’ is a sustainable alternative to refrigerants

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These findings were published in the journal Science in December.


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JANUARY 11, 2023

Researchers at Lawrence Berkeley National Laboratory, or Berkeley Lab, discovered a new method of refrigeration called ionocaloric cooling, which could help reduce the effects of global warming.

The findings were published in the journal Science in December.

Prior to their work on this project, Drew Lilley, UC Berkeley graduate student and head researcher, and Ravi Prasher, senior scientist at Berkeley Lab, collaborated on another study about dynamic tunability of phase-change materials. The pair felt inspired to create a similar thermodynamic cycle that could be used instead for refrigeration and heat pumping, according to Lilley.

“It’s a new way to make things cold or hot,” Lilley said. “Normal cooling uses something called vapor compression — you basically take a gas, compress it, and it heats it up and when you expand it, it cools it down. Instead of using a vapor, (ionocaloric cooling) uses a solid, and instead of a compressor it uses salt.”

Lilley explained how the process of adding and removing salt to and from the solid caused the solid to heat up. Simply stated, “the ion drives the heat.”

Traditional refrigerants, or the gas used in cars, air conditioners and refrigerators, among others, contribute to a large portion of global warming issues, according to Lilley. He noted that most people are unaware of refrigerants’ severity on the environment.

“For perspective, in about 20 years it is projected that roughly 20% of the equivalent carbon dioxide emissions will be caused directly by refrigerants,” Lilley said. “So, by 2040 and 2050, each year, 20% of our additional contribution to global warming will be caused by these refrigerants leaking into the atmosphere. That’s a pretty staggering number on a global scale.”

Early refrigerants created a sizable hole in the ozone layer and were replaced by chlorofluorocarbons, which also created significant damage to the atmosphere, even though they did not deplete the ozone layer, Lilley noted. He explained these refrigerants cause harm by leaking and creating a blanket-like layer in the atmosphere.

Ionocaloric cooling offers an environmentally conscious alternative, he said.

“It’s zero global warming potential, non-toxic, non-flammable and non-hazardous — you name it,” Lilley said. “It just provides a good alternative that doesn’t harm the environment.”

Prasher and Lilley plan to commercialize the method, according to Lilley. Although, Lilley recognized more research and development is needed before ionocaloric cooling can completely replace traditional systems.

Lilley is optimistic about the application of the method moving forward.

“The future is bright,” Lilley said. “I think this certainly can at some point replace most cooling applications. It’s just going to take research and development, and a lot of smart people to work on it, but the potential is there in terms of performance (and) cost. Now it just needs a lot of work.”

Contact Lucía Umeki-Martínez at 


JANUARY 11, 2023