A compressor dehumidifier works by using condensation to extract water from the atmosphere. The dehumidifier draws in warm, humid air, which then passes over a refrigerated coil. When warm air passes over the coil, moisture is removed from the air via condensation.
A desiccant dehumidifier uses adsorption, a process in which liquid molecules adhere to a surface. Humid air is drawn into the dehumidifier and passed over a desiccant wheel containing silica gel, which adsorbs excess humidity. The dehumidifier then outputs dry, warm air.