Laundry day is on the brink of a time and energy-saving revolution after US researchers developed a new system that dries clothes with ultrasonic vibrations instead of heat.

Oak Ridge National Laboratory and GE Appliances researchers are developing a prototype that uses high-frequency shaking to extract moisture as a cold mist, dramatically reducing drying time and energy use.

The study focused on using ultrasonic transducers with an energy factor that greatly exceeds current heat-based technology. Drying times could be reduced to 15 to 20 minutes with potentially no shrinkage, no fading and no lint.

"This project can potentially revolutionize the clothes dryer industry and provide 117 billion kilowatt-hours in energy savings," said Ayyoub Momen of the lab's Building Technologies Research and Integration Center.

The research team say the direct-contact ultrasonic drying is a novel, transformative drying technology that is completely different from conventional heat drying systems.

As well as reducing both energy consumption and drying time significantly, the new system provides a quieter drying process. Since a high air flow of hot air is not needed, lint production would be minimized.

Recent research has shown that industrial ultrasonic food drying is the most effective method for the most porous food products, suggesting that clothes, which are naturally very porous, might be the best area for the use of ultrasonic drying.

The high-frequency vibrations form an extremely fine, cold mist of droplets about 1 micron in diameter that carry away most impurities present in the water, such as minerals and detergents.

The researchers say their process may provide additional benefits, such as softer clothes and a reduction in rinse water needed in the washing machine.

Anh Tuan