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Innovation Economy

Somerville startup has a cool take on air conditioning

Chief executive Sorin Grama of Transaera, a startup developing a more energy-efficient air conditioner, during a demonstration inside the company's environmental test chamber in Somerville Tuesday.Jonathan Wiggs/Globe Staff

Transaera, a tiny startup based in Somerville, is trying to tackle a big problem: air conditioning.

As the planet warms, more people want it. According to the International Energy Agency, a Paris-based intergovernmental organization, the demand for AC could triple by 2050, driven largely by consumers in China, India, and Indonesia. And cooling technologies like AC and electric fans account for about 20 percent of the energy consumption in buildings, the IEA notes. That produces more carbon dioxide emissions, which accelerate warming, which spurs more demand for cooling. It’s quite the negative feedback loop.

Transaera, and a handful of other startups, is working to design air conditioners that require dramatically less energy. This month, the company plans to announce that it has raised an initial funding round of $4.5 million. One of its backers is Carrier Global Corp., the publicly traded Florida company whose founder is credited with inventing modern air conditioning systems in the early 20th century.

Transaera’s founder, Sorin Grama, is one of the godfathers of Boston’s clean energy startup ecosystem. In 2007, he cofounded a company called Promethean Power Systems, which developed and sold a new kind of milk chiller in India, one that doesn’t require a dirty diesel generator to keep the milk collected from farms cold. In 2010, looking for a workspace where Promethean could build and test its prototype chillers, Grama helped start Greentown Labs in a vacant building that once housed a printing operation. Greentown is now the country’s biggest incubator for clean energy companies, with about 125 tenants — including Transaera.


After extracting himself from the day-to-day operations of Promethean, Grama says he began “casting about for some new ideas to work on, but eventually I came back to cooling.” Grama met an MIT professor, Mircea Dincă, who was studying a kind of porous crystalline material called a metal-organic framework, or MOF. Grama and Dincă cofounded Transaera in 2018 and supported their early work with about $2 million in state and federal grants, from agencies that included the Massachusetts Clean Energy Center.


Gram and Dincă decided to focus on air conditioning in part because of the Global Cooling Prize competition, which ponied up $3 million in prize money to incentivize startups and large companies to design radically more efficient air conditioners. (Transaera was not one of the two winners, but it was one of eight finalists.) A key to their design was using the MOF material as a kind of sponge, to pull moisture — aka humidity — out of the air.

Holding up a small test tube of MOF powder, Ross Bonner, Transaera’s chief technology officer, says that the powder inside has “roughly the same surface area as a football field.” MOF is a kind of desiccant — not unlike the silica gel that is used in packaging food or electronics to keep moisture out. But when MOF absorbs water molecules, it “doesn’t hold onto the water tightly,” Bonner explains. Using heat that is already circulating in the air conditioning unit, he says, it can release those water molecules trapped by the MOF material as water vapor. The vapor is expelled from the unit.

Grama explains that the MOF material is what makes Transaera’s air conditioner more energy efficient; today’s air conditioners require more electricity to pull water from the air and turn it into a liquid. “It’s beneficial from an energy standpoint, but it’s also a feature: without water, there are no drips, no mold, and no leaks,” he says. The company’s objective is to deliver the same cooling power as a traditional air conditioner, with half the energy usage, Grama says. The air conditioner also uses a refrigerant called R32 to cool the air, which is more environmentally friendly than those commonly used today. (Refrigerants are a potent greenhouse gas that can leak during use or when the device is improperly disposed of.)


MOF powders have only been around for about 20 years, and a big part of Transaera’s “secret sauce” is how the MOF material is applied to a surface inside the air conditioner, so it can act as a sponge. “The challenge is to make the coating rugged and durable enough to survive for the life of the device, so it won’t come right off,” Grama says.

The cost and scalability of using MOF material in air conditioners in high-volume production could be an issue, says Michael Holman, a vice president who focuses on energy and manufacturing at Lux Research, a Boston-based analyst firm. “I know there are lots of claims from different firms to have innovations that will solve this, but we haven’t really seen it proven yet,” Holman writes via e-mail.

Transaera envisions developing this technology and licensing it to companies that already have manufacturing facilities and distribution channels — among them are Carrier and Windmill, a New York startup.


Energy Impact Partners, one of the investment funds that is putting money into Transaera, discovered the company through the Global Cooling Challenge. Ashwin Shashindranath, a partner at EIP, says he was attracted to the company because its technology can be used in a variety of products — not just air conditioners for homes, but rooftop units for commercial buildings, and built-in wall units found in hotels.

“The air conditioning space is dominated by large companies, incumbents, that have been working on evolutionary technology changes over time ― and nothing revolutionary,” Shashindranath says.

With temperatures in many parts of the world setting records, “This is the summer that air conditioning is getting the attention it needs,” Grama says. “You’re seeing investors more interested” in a sector that was once considered “kind of a backwater.”

But that will create competitors for Transaera — among them, Florida-based Blue Frontier, which announced a $20 million funding round earlier this month. Its focus is rooftop air conditioners for big buildings, and among its investors is Breakthrough Energy Ventures, an investment vehicle created by Bill Gates in 2016.

Carmichael Roberts, based in Boston, helps choose the startups that Breakthrough puts money into. As “air conditioning makes the transition from a luxury product to a utility product” in many developing economies, Roberts says there is a real need for new approaches to energy efficiency. But air conditioning is a conservative market where price matters — a lot, he adds.

“This just means it is going to take real breakthroughs to make headway,” Roberts says.


Scott Kirsner can be reached at kirsner@pobox.com. Follow him @ScottKirsner.