Which type of dehumidifier uses silica gel?

• A. Refrigerant dehumidifier
• B. Ultrasonic humidifier
• C. Desiccant dehumidifier
• D. Ionizing dehumidifier

Answer: (C)

Silica gel is a desiccant, a material that actively absorbs moisture from the air. A desiccant dehumidifier uses this material to remove humidity: air passes through a bed (or wheel) of silica gel and water vapor is absorbed. The desiccant is then regenerated by applying heat, which releases the moisture so the gel can absorb again. This approach is different from refrigerant dehumidifiers, which remove moisture by cooling air until it condenses on chilled coils, and from ultrasonic humidifiers or ionizing dehumidifiers, which don’t rely on a desiccant to remove moisture.