A tumble dryer that is claimed to dry clothes twice as fast has been developed in the US.

The machine uses high-frequency sound waves instead of heat to dry laundry.

As well as speeding up the drying process, it is expected to use up to 70% less energy than conventional dryers.

The dryer has been developed by scientists at Oak Ridge National Laboratory, Tennessee, in partnership with General Electric.

Shaken dry

The inner lining of the drum of the machine is fitted with small sheets that convert an electric signal into vibrations.

These are at a high enough frequency that they can shake the water out of clothes, in the form of a cold mist.

The water is driven into the outer part of the drum, where it flows down to a collection tank.

According to the US Department of Energy, which supported the project, standard clothes dryers take an average of 50 minutes to dry a medium-sized load.

The prototype model can dry the same amount of laundry in about 20 minutes.

Lack of lint

The research has been driven in part by the fact that the basic technology used in clothes dryers – heating the air to evaporate water out of clothes – has not changed in decades.

“We have seen breakthroughs like injecting bubbles into washing machines to wash the clothes more effectively,” commented Jane Westgarth, a senior analyst at Mintel.

Another advantage of the ultrasonic technology is that it appears to generate far less lint.

Most of the lint created in conventional tumble dryers is the result of tiny fibres being dislodged from clothes by the hot air stream.

As well as causing extra wear on the fabric, the heat can fade clothes over time.