When the experimental results came back, they puzzled Adam Slavney and Jinyoung Seo. They had been testing a new class of materials for more efficient refrigerators, air conditioners, and heat pumps, a mission that the cooling appliance industry has been on for eons. The measurements for the materials that the team was testing shouldn’t have been different, but they were.
“Why are these things different? What did we change?” Slavney told TechCrunch. “We had an inkling of it within three-ish months, but we didn’t have definitive proof for a year or two.”
That proof is now underpinning Slavney’s startup, Pascal, where he’s co-founder and CEO and Seo is co-founder and CTO. The company recently raised $8.5 million in a follow-on to its seed round, co-led by Sazze Partners and LB Investment with participation from KDB Silicon Valley, the company exclusively told TechCrunch.
A refrigerator or heat pump using Pascal’s material promises to be around 20% more efficient than existing models, he said. (Both heat pumps and refrigerators use the same basic technology.) The startup has signed a contract with a multinational beverage company for a pilot of the technology.
“This whole funding round came together originally because we got a customer contract earlier than we were expecting to,” Slavney said. Pascal is on track to deliver its first prototype early next year, and it hopes to follow that with a batch of more polished refrigerators in 2028.
Scientists have been searching for better refrigerants for almost as long as refrigerators have existed. More recently, they’ve been looking for compounds that don’t harm the atmosphere in one way or another. They exist, but they also need to be at least as effective as existing refrigerants.
“We’ve been playing whack-a-mole with refrigerants for 35 years, 40 years,” Slavney said. Older gaseous refrigerants like Freon ate a hole in the ozone layer, while newer ones like R-134a are still extremely potent greenhouse gases. “It’s just a never-ending treadmill,” he said.
One alternative that has attracted researchers’ attention is a class of materials known as solid-state refrigerants. Because they’re solid, they can’t escape to the atmosphere, eliminating the climate and ozone concerns that haunt modern refrigerants. Solid-state refrigerants promise to make refrigerators and heat pumps more efficient. They work similarly to traditional refrigerants, giving off heat when squeezed and absorb it when that pressure is released.
Before his serendipitous discovery, Slavney and his colleagues at Harvard University had been researching the materials. “We wanted to do some high-pressure measurements, and the instrument that we were using required us to use gas. So we used the gas and then we swapped to a different gas and we were like, why are these different?” Slavney said.
After numerous additional experiments, the team realized they had discovered another path toward solid-state refrigeration. Rather than squeeze a solid block of material, Pascal’s heat pumps compress a gas — carbon dioxide — into a cartridge that contains a sponge-like material, which Slavney said is proprietary.
As the carbon dioxide works its way into the porous material, the gas molecules inside the pores start bouncing off the walls. Those collisions transfer energy to the material, warming it up. A heat exchanger then exhausts some of that heat. Run it in reverse and the material absorbs energy from the heat exchanger and transfers it to the carbon dioxide molecules.
In a Pascal refrigerator, two cartridges are running at any given time. One is absorbing heat from the inside of the refrigerator, transferring it to the carbon dioxide, while the other takes the heat from the carbon dioxide and transfers it to the outside air. Eventually, the cartridges become too hot and too cold, so the flow gets reversed.
“The material is very robust,” Slavney said. “We’ve cycled it up to 300,000 times. It’s the equivalent of a year or so in operation.”
The entire system moves heat more effectively than other solid-state refrigerants, which means that Pascal doesn’t have to operate at high pressures like other solid-state refrigerants might demand.
“We’re using conventional systems to do it,” Slavney said. “That mean we believe we can make it cheap, and that means we can make it widespread.”
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Tim De Chant is a senior climate reporter at TechCrunch. He has written for a wide range of publications, including Wired magazine, the Chicago Tribune, Ars Technica, The Wire China, and NOVA Next, where he was founding editor.
De Chant is also a lecturer in MIT’s Graduate Program in Science Writing, and he was awarded a Knight Science Journalism Fellowship at MIT in 2018, during which time he studied climate technologies and explored new business models for journalism. He received his PhD in environmental science, policy, and management from the University of California, Berkeley, and his BA degree in environmental studies, English, and biology from St. Olaf College.
You can contact or verify outreach from Tim by emailing [email protected].