A typical clothes dryer works the same way dryers have worked for decades—blowing hot air in an energy-sucking process that costs Americans $9 billion a year. A new prototype uses sound waves instead, vibrating clothes dry rather than heating them up.
Evaporating the water in clothes is energy intensive and, thus, very expensive. The vibrations still take energy to create, but much less. "You're drying it as it's cold," says Ayyoub Momen, a researcher at Oak Ridge National Laboratory who is developing the new technology. "That significantly helps improve the efficiency."
Momen was inspired to create the new prototype one day as he watched an ultrasonic humidifier work. "I saw how much cold mist it can generate with just a little bit of energy, and that rang a bell for me," he says. "I said, well, can we apply the same physics to fabric drying?"
In their first experiment, they were able to dry a piece of fabric in a record 14 seconds. The current small prototype looks a little like a fog machine as mist billows from samples of fabric.
When the technology is scaled up to a full dryer, a load of laundry might take 20 minutes, rather than the 40-50 minutes that it might take in another dryer. Because clothes aren't blasted with heat, the researchers expect that they will also last longer. The process also minimizes lint.
It's likely to be three to five times more efficient than a typical dryer. An upgrade to dryers was long overdue; an electric dryer today might use as much energy as an efficient washing machine, dishwasher, and fridge combined.
When the EPA started giving some washing machines the Energy Star label 20 years ago, it left energy-sucking clothes dryers off the list, reasoning that all dryers were equally bad. It was only in 2014, when the first European-style heat pump dryer came to market in the U.S., that dryers were added to the Energy Star program. Heat pump dryers recapture heat, but are expensive. Ultrasonic dryers may be another alternative. The researchers are working with GE to try to bring it to market.