Desiccant dehumidifiers work on the principle of sorption with the key component being a slowly turning desiccant impregnated rotor or wheel; typically silica gel. The rotor revolves through two seperate air streams; process and reactivation.Process air enters the unit and the desiccant sorbs water vapour. The dehumidified process air then exits the unit and is delivered to the affected area.
The water vapour is sorbed by the rotor from the process air stream is then desorbed in the reactivation air stream. The reactivation air stream is heated, causing the desiccant to release its moisture. The moisture-laden reactivation air then exits the dehumidifier and is delivered to the outdoor environment. Desiccant dehumidifier utilise vapour differential to remove water and can be effective across a broad range of atmospheric conditions. To compensate for sensible heat gain in the affected area, Pre-cooling the desiccant or post-cooling may be added to process the air stream of the desiccant as well as deliver a lower process outlet temperature.