“It’s not the heat that bothers you, it’s the humidity,” a father once said somewhere.
His children may roll their eyes, especially if they have ever been to the desert in the southwest of the country in the summer, but their father is at least partially right: High humidity not only worries people, it also puts a strain on air conditioning systems. Half of the energy used by a typical air conditioner is used to remove moisture from the air.
For companies like Amazon, Walmart, UPS and FexEx that operate massive warehouses, air conditioning is a growing problem. Temperatures inside warehouses can become uncomfortably and potentially dangerously hot.
A startup is working to solve the humidity problem. Transaera is developing a unique air conditioning system for homes and apartments that uses a special material to remove moisture before cooling the air. With more than 2 billion people in hot, humid regions still lacking air conditioning, the company hopes it can help meet that need while reducing energy consumption.
But first, while the company refines the product for consumers, it’s deploying larger units for commercial buildings like warehouses. On Tuesday, the first of these was installed on a customer’s roof, the company told TechCrunch exclusively. This dedicated outdoor air system (DOAS) dehumidifies the fresh air coming into the building, reducing the load on the air conditioning system.
“DOAS is a small part of the market, but it’s a growing segment,” co-founder and CEO Sorin Grama told TechCrunch. “It’s just an easier entry point.”
Founded in 2017, the Somerville, Massachusetts-based startup has raised $7.5 million so far, including $4.5 million in a seed round, Grama said, and is currently raising $6 million to support field testing 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 that 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 generate heat as they remove moisture from the air. Normally, this heat is lost, but Transaera reuses it to remove moisture from its desiccant, which is located on a porous wheel. As the wheel passes through the incoming air, it picks up moisture. The charged desiccant then rotates away from the incoming air and through the waste heat from the evaporator coils. The warm air carries the unwanted moisture outside. In winter, the system can reverse its function, helping to maintain humidity indoors while the heat pump warms the incoming air.
Many other DOAS systems installed on roofs of commercial properties today also use heat pumps to dehumidify the incoming air. But because these rely on cold temperatures to condense the water on the coils, the air coming out of them can be too chilled compared to the air inside 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 with natural gas. “That’s a really inefficient and stupid way to run these particular outside air systems,” Grama said.
Transaera’s approach uses up to 40% less energy than current top-of-the-line DOASs, he said. Currently, the company’s technology is installed on one commercial rooftop, but Grama said more will follow. There’s a sense of urgency: Because removing moisture requires so much energy, it’s responsible for 1% of all greenhouse gas emissions, according to a recent study. That’s about half of what aviation generates, a sector that gets far more attention. Reducing dehumidification energy use by 40% would significantly reduce that figure. Papa would approve.
