History repeats itself, sometimes more frequently than we might like it to. Case in point: last year was the hottest year on record. And while that exact trend hasn’t occurred sequentially each year over the previous decade, the world is firmly in the throes of ceaseless warming patterns.

Context necessitates cooling

Average global temperatures in 2023 stood at 14.98°C, surpassing the previous record-holder of 14.81°, set in 2016. Forbes reported earlier this year that 2023 was the “first year with all days over 1°C warmer than the pre-industrial period,” according to Samantha Burgess, deputy director with the EU’s Copernicus Climate Change Service. We are well within the margin of error of the 1.5° threshold established in the Paris Agreement—signed by 196 parties at COP21—that it is now a foregone conclusion. If we haven’t passed it yet, we surely will next year, and then some.

There is also a cruel irony in the fact that, given that maximum warming occurs approximately 10 years after the initial GHG emissions, we are now or soon will be experiencing extreme heat—and assuredly setting new records—associated with carbon emissions that went out around the time the Paris Agreement was signed.

All of this presents us with a sordid conundrum. We need to do more to cool our built environments (2023 also set a record for heat-related deaths in the U.S.), while also curbing an ever-increasing electricity demand that comes from conditioning more and more built space.

Additionally, many billions of people living in humid, equatorial climates currently lack access to air conditioning but could certainly use it to avoid heat-related stresses. (We can’t all be Germany.)

More efficient cooling

Most of the world’s vapor-compression ACs are inefficient energy hogs, with older systems employing CFC and HCFC refrigerants that, when leaked, have a global warming potential many thousand times greater than CO2 and an atmospheric shelf life of several decades. Newer systems are markedly better and healthier, including air-source heat pumps, but they still operate on the same basic vapor-compression principle of cycling refrigerants to cool and dehumidify air simultaneously, and releasing waste heat outside.

In response to this unsustainable practice, several startups are developing technologies that aim to do more with less. One such company is the MIT spinout Transaera, founded in 2017 (and a neighbor of Sublime Systems within the Somerville, Massachusetts, climate-tech incubator space Greentown Labs). Transaera’s hybrid cooling system uses a proprietary heat exchanger coating that removes atmospheric moisture before cooling the air, and the heat produced by the AC is used to dry the coating material for its next cycle rather than being sent outside as waste heat.

“All air conditioning is two things: dehumidifying and cooling. We don’t think so much about dehumidifying, but dehumidifying is actually a bigger portion of the AC’s energy consumption. With today’s ACs, you have to over cool the air to turn it into water,” says Sorin Grama, Transaera’s CEO.

Grama describes the coating material as a “desiccant on steroids.” It’s in a class of absorbent materials that have only been researched for industrial use for no more than 20 years, he says, while noting Transaera’s cooling systems represent their first commercial application. Like “a thin coating of paint on substrate,” Grama observes, air passes through what’s known as a metal organic framework, where water molecules are trapped by the desiccant coating on the filter.

“We then use the waste heat that’s in the air conditioner to dry the framework,” Grama continues. “So now the whole combined process of dehumidifying and cooling is much more efficient … almost twice as much as a conventional air conditioner, [and with no residual condensation].”

He adds that his company’s cooling systems, which are currently being developed for rooftop units that service large commercial and industrial buildings, are also low maintenance, with filters that can withstand “multiple absorption and desorption cycles” and will need replacing “every two or three years, sometimes longer.”

Starting big

Transaera remains a pre-commercial startup for the time being, with field trials of its units getting underway only in the last few months. The first such trial is a for confidential corporate client in Houston, with rooftop air conditioners getting installed on a large commercial building. The company is fully out of the lab and ready to go to market, and Grama is optimistic that this trial will help speed up that process.

“A lot of big tech customers are looking to decarbonize their buildings, and they’ve made commitments for net-zero operations,” Grama says. “They are willing to try these technologies and roll them into their operations.” Any calculated risk such customers may feel they’re taking will be blunted by the fact that Transaera’s systems are of similar weight, size, and cooling capacity as conventional rooftop units, according to Grama, making the job of installing and maintaining them easier for HVAC technicians.

Grama admits to having his sights set on global markets but concedes that Transaera is entering into a conservative industry, where emerging technologies can be met with considerable friction. Making matters even harder, Grama lays out Transaera’s short-term business plan by saying, “We’re building full systems and delivering them directly to end users. We’re going to do that for a while.”

Indeed, commercial and industrial facilities located in the American Southeast are a smart place to start, and with the right clients, will provide good visibility for future growth. Beyond that immediate horizon, the company clearly knows where demand is greatest. “Look at Southeast Asia, Mexico, Brazil, all these countries have very little penetration of air conditioning,” says Grama, “but it’s coming. They’re adding [ACs] at a much faster pace than we are in the U.S. The highest demand and growth for air conditioning is overseas.”

Investing in startups

When it comes to adopting new technologies that offer greater operational efficiency for buildings, Grama describes a brave new world where large companies are now willing to invest in startups like Transaera. Big sustainability groups are actively “surveying the market,” he says, and are keen on paying a premium for being part of pilot projects. “Otherwise, if you don’t create this environment, the old order will prevail.”

To curtail that outcome, Grama and his industry peers know that diversifying their offerings is needed. Entering into licensing agreements with other AC manufacturers, designing Transaera’s metal organic frameworks into existing AC models, and selling entire units wholesale to energy service providers and similar companies, as opposed to direct consumer sales, are all possible future avenues. Of note, the company has also partnered with Fresco Design on developing portable AC units for residential use.

For his part, Grama sees great promise in ongoing shifts within financial markets, and among industry players who clearly see the net-benefit of doing more with less, i.e., plugging in more customers while drawing down overall emissions.

“Even before tax breaks and all that, utilities are actually giving money to customers to incentivize them to buy more efficient equipment,” he says. “And the reason for that is pretty interesting. Utilities will look at the cost of and growing demand for electricity and say, okay, our choice is either to build a new power plant for a billion dollars, or we can subsidize consumers to reduce their energy consumption.”

When he puts it that way, the choice does seem obvious.

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