Anika Begay
“It’s not the heat that kills you, it’s the humidity,” said a dad, somewhere.
His kids might frown, especially if they’ve spent time in the desert Southwest over the summer, but their dad is at least partly right: Not only does high humidity make people less comfortable, it also puts a strain on air conditioners. Half the energy used to power a typical air conditioner is spent removing moisture from the air.
For companies like Amazon, Walmart, UPS, and FedEx, which operate massive warehouses, air conditioning has become a growing concern. Temperatures inside warehouses can become uncomfortable, potentially dangerously hot.
One startup has been working to solve the humidity problem. Transaera is developing a unique air conditioner for homes and apartments that uses a special material to remove humidity before cooling the air. With over 2 billion people in hot, humid regions still without air conditioning, the company hopes to help meet that demand while reducing the amount of energy required.
But first, as it refines its product for consumers, it’s rolling out larger units for commercial buildings like warehouses. It installed the first of these on a customer’s rooftop on Tuesday, the company told TechCrunch exclusively. This dedicated outdoor air system (DOAS) dehumidifies fresh air entering the building, reducing the load on the air conditioner.
“DOAS is a small slice of the market, but it’s a growing segment,” co-founder and CEO Sorin Grama told TechCrunch. “It’s just an easier entry point.”
The Somerville, Mass.-based startup, founded in 2017, has raised $7.5 million to date, including a $4.5 million seed round, Grama said. It is currently raising $6 million to support field trials of its equipment.
Transaera’s core technology is a proprietary material that coats the heat pump’s heat exchangers, which resemble a car’s radiator. In Transaera’s DOAS, air entering the unit passes over the special material, which removes moisture from the air. The drier air then hits the evaporator coils, which cool the air to match the temperature inside the building.
Air conditioners and dehumidifiers all generate heat in the process of removing moisture from the air. Usually, that heat is wasted, but Transaera reuses it to pull moisture away from its desiccant material, which is on a porous wheel. As the wheel passes through incoming air, it absorbs moisture. The charged desiccant then rotates away from the incoming air and through waste heat from the evaporator coils. The warm air carries the unwanted moisture outside. In the winter, the system can reverse, helping to preserve indoor humidity while the heat pump warms the incoming air.
Many other DOAS systems now found on commercial rooftops also use heat pumps to dehumidify incoming air, but because they rely on cold temperatures to condense water on coils, the air coming out can be excessively cooled compared to the air in the building (especially in the spring and fall, when temperatures may not be warm enough to require air conditioning). The units then have to reheat the air, often using natural gas. “It’s a really inefficient and stupid way to do these dedicated outdoor air systems,” Grama said.
Transaera’s approach uses up to 40% less energy than current high-end DOAS, he said. For now, the company’s technology lives on a commercial rooftop, but Grama said more is coming. There’s some urgency: Because removing humidity requires so much energy, it accounts for 1% of all greenhouse gas emissions, according to a recent study. That’s about half of what aviation generates, an industry that’s received much more scrutiny. Reducing energy use for dehumidification by 40% would make a serious dent in that. Dad would approve.
