What is the function of the cooling coil in centralized humidification systems?

• A. To dehumidify the air while maintaining comfort levels.
• B. To add moisture to the air.
• C. To heat the air to comfort temperatures.
• D. To purify the air using filters.

Answer: (B)

In centralized humidification, the goal is to raise the moisture content of the supply air. The cooling coil serves as the wetted surface where water evaporates into the moving air. As air passes over or through the humidifier section on the coil, water vapor is added to the air, increasing its humidity to meet the desired setpoint. This is distinct from cooling to dehumidify, heating the air, or filtering it; those functions are handled by other parts of the system, while the cooling coil’s role here is to enable evaporation and deliver moisture.