Available Modules

Humidity Control – Dry Desiccant Systems

A dry or solid desiccant system uses special crystal-like materials (a desiccant) that “adsorb” moisture from the incoming air. In a typical system, the desiccant is mounted on a rotating wheel that resembles a round honeycomb. Holes in the honeycomb are coated with solid desiccant material. As the wheel turns, the desiccant passes alternately through the incoming process air where the moisture is adsorbed and through a regenerating zone where the desiccant is dried and the moisture expelled.

Typically, about three-fourths of the desiccant wheel is exposed to the incoming air throughout the process. As the desiccants continue to pick up moisture, their ability to adsorb at 100% is diminished. During regeneration, the desiccant is heated by a direct-fired gas burner or indirect-fired water or steam coil. The heat evaporates the moisture, releasing it into the atmosphere, while the desiccants regain their maximum absorption ability.

Dry desiccants systems are limited by the volume of air that can be processed through the desiccant wheel and, therefore, are better suited to smaller and modular applications.