The dehumidifiers are of the solid wheel desiccant type and operate using two air streams; One larger air volume which is to be dehumidified, and one considerably smaller air volume for reactivation of the desiccant rotor.

As the larger air volume (process air) passes through the slowly rotating rotor, the water vapour is adsorbed by the rotor material. This reduces the humidity of the air which will then leave the dehumidifier as dry air. This dry air is then introduced into the space to be dehumidified or to any manufacturing process where low humidity is required.

To remove the moisture captured in the desiccant rotor, the smaller air volume (reactivation air) which flows counter to the dry air, is heated up in a heating coil before entering the rotor. As this warmer air is passed to a smaller segment of the rotor, the rotor material will release its moisture (desorb) into this air volume. The moisture will leave the dehumidifier as wet air, which is then expelled away from the space that is to be humidity controlled.