Cooling homes without warming the planet

As incomes in developing countries continue to rise, demand for airlines is expected to double by 2050. The increase will multiply what is already in place. main source of greenhouse gas emissions: Air conditioning currently accounts for nearly 20 percent of electricity use in buildings around the world.

Now the startup Transaera is working to limit these energy demands with a more efficient aircraft that uses safer refrigeration devices to cool homes. The company estimates that its device could have one-fifth impact on the climate compared to traditional ACs.

“The thing about air-conditioning is that the underlying technology hasn’t changed much since it was created 100 years ago,” says Transaera chief engineer Ross Bonner SM ’20.

That will change quickly if a small Transaera team succeeds. The company is currently in the final round of a global competition to redesign the aircraft. The winner of the competition, which has the global cooling prize, will receive $ 1 million to commercialize its equipment.

At the heart of Transaera’s design is a class of highly porous materials called organic metal frames, or MOFs, that passively absorb moisture from the air as the machine works. Co-founder Mircea Dincă, WM Keck Energy Professor in MIT’s Department of Chemistry, has conducted innovative research on MOFs, and company team members see the commercial advancement of the products as an important part of their mission.

“MOFs have many potential applications, but what is holding them back is unit economics and the inability to do so in a cost-effective manner at scale,” says Bonner. Transaera aims to be the first to trade MOFs at scale and lead the way in bringing MOFs into the public domain. “

Dincă co-founders are Transaera CEO Sorin Grama SM ’07, who is also a lecturer at MIT D-Lab, and CTO Matt Dorson, a mechanical engineer who previously worked with Grama.

“I’m just inspired by this idea of ​​creating something revolutionary,” says Grama. “We’ve designed these new tools, but we’re also bringing this invaluable experience, with Mircea and our colleagues, and mixing the two to create something very new and different. create. “

Fair stuff

Grama and Dorson previously collaborated at Promethean Power Systems, which develops off-grid cooling solutions for farmers in India. To date, the company has installed 1,800 cooling systems that serve approximately 60,000 farmers per day. After retiring as CEO in 2015, Grama returned to the Institute to teach at MIT D-Lab and served as a resident entrepreneur at the MIT Martin Trust Center for Entrepreneurship.

During that time Grama was introduced to MOFn by Rob Stoner, deputy director of the MIT Energy Initiative for science and technology and founding director of the MIT Tata Center.

Stoner introduced Grama to Dincă, who had been studying MOFs since joining MIT faculty in 2010 and grew up 10 miles from Grama’s hometown of Romania.

The interesting properties of MOF come from their large interior surface area and the ability to fine-tune the size of the tiny rooms that run through it. Dincă previously developed MOFs with vertical chambers large enough to capture water molecules from the air. He described them as “sponges on steroids.”

Grama began to think about using the material for cooling, but it wasn’t long before another application emerged. Most people think that air conditioners not only cool the air in place, but also dry the air they are cooling. Traditional appliances use something called an evaporator, a cold coil to draw water out of the air through condensation. The cold coil must be made much colder than the desired temperature in the room to accumulate moisture. Dorson says drawing moisture out of the air accounts for about half of the electricity used by traditional aircraft.

MOFs Transaera passively collect moisture as air enters the system. The waste heat of the machine is then used to dry the MOF material for continuous reuse.

Transaera was formally established in early 2018, and the World Cooling Award was announced later that year. Hundreds of teams showed interest, and Transaera was eventually selected as one of eight finalists and received $ 200,000 to deliver prototypes to tournament organizers.

Bonner joined the company in 2019 after exploring pathways to carbon neutral ACs as part of a mechanical engineering class at MIT.

As COVID-19 began sweeping through countries around the world, it was decided that Cooling Award trials in India would be run remotely. Adding to the challenge, the co-founders did not have access to their laboratory in Somerville due to limitations and were using their own tools and garages to complete the prototypes. After sending out their prototypes, Transaera had to help award organizers to install them through live video feeds for field trials in several locations in India. The team says the results confirmed Transaera’s approach and showed that the systems had significantly lower climate impact than baseline units.

The Transaera system also used a cooler called R-32 with zero ozone depletion capability (ODP) and global warming capacity about three times lower than other commonly used coolers.

The milestone gave Transaera’s small team more confidence that they were on something.

“This air conditioning problem can have a very significant impact on people’s quality of life,” Dorson says.

Pushing a field forward

The Prize will announce the winner of next month’s global cooling. Whatever happens, Transaera will grow the team this year and run additional trials in Boston. The company has been working with major manufacturers who have provided equipment for prototypes and shown the founders how they could integrate their equipment with the latest technologies. ‘ann.

The company’s establishment work with MOFs has continued even as the Transaera aircraft comes closer to trading. In fact, Transaera recently received a grant from the National Science Foundation to study more efficient pathways to MOF production with a laboratory at MIT.

“MOFs open up so many opportunities for all sorts of revolutionary devices, not just in air conditioning, but in water harvesting, energy storage, and super capacitors,” says Grama. this knowledge that we are developing is relevant to so many other applications down the road, and I feel like we are pioneering this field and pushing the edge of technology . “

However, the founders of Transaera are still aiming to bring their AC to market first, recognizing that the problem they are trying to tackle is big enough to keep them busy for a while.

“It’s clear when you look at the swath of the world in the hot, humid tropics, middle class is growing, and one of the first things they want to do is buy an aircraft,” he said. Dorson says. “The development of more efficient air-conditioning systems is critical to human health and the environment of our planet.”

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This story is republished with permission from MIT News (web.mit.edu/newsoffice/), a popular site covering news about MIT research, innovation and teaching.