Regenerative desiccant compressed air dryers reuse desiccant beads by drying saturated beads through a heatless twin-tower process. While one tower dries compressed air, the other tower dries saturated desiccant using a portion of the compressed air supply. Because a small amount of compressed air is diverted and used to dry the desiccant beads, there is a slight drop in the total air flow (cfm) available to downstream tools. Regenerative dryers need a power source and can provide a continuous supply of dry compressed air at lower dew points than standard desiccant dryers.