RNR/ Exal twin tower heatless dryers work on pressure swing adsorption in order to dry and regenerate Air/ Gas. While one tower is under adsorption the second tower is under regeneration. In order to regenerate a tower a partial stream of Air/ Gas at close to atmospheric pressure is passed over the bed. As atmospheric air has higher capacity to hold moisture vs pressurized Air/ Gas, only a partial stream of gas is necessary in order to regenerate the bed.

Heatless dryers can attain excellent and steady dewpoints.