What Is A Dry Cooling Coil?

What is a dry coil?

A dry cooling coil is a terminal device primarily used to provide cooling or heating to indoor return air.

Since these units operate with high chilled water temperatures above the dew point, little to no condensation forms on the unit's exterior, hence the name “dry coil.”

Primary Applications

Dry fan coil units are employed in limited scenarios, primarily within constant temperature and humidity air conditioning systems for cleanrooms composed of MAU, FFU, and DC components. Their main function is to eliminate sensible heat (heat generated by people, lighting, machinery, etc.) to control indoor temperatures. Examples include clean laboratories, hospital sterile operating rooms, and clean production workshops.

Differences from Conventional Fan Coils

Standard fan coils connect directly to chilled water. During summer operation at 7°C chilled water supply temperatures, condensation readily forms under high humidity conditions. Dry coils, however, utilize chilled water heated to 12–14°C through heat exchange—significantly above the corresponding condensation temperature of indoor air—thus preventing or minimizing condensation.

Additionally, dry coils lack condensate drain pipes, though drip pans are typically installed as a precaution.

Key Advantages

- Eliminates condensate, reducing leakage risks and minimizing bacterial/microbial growth.

- Requires higher refrigerant temperatures, enhancing central air conditioning unit efficiency for energy savings and reduced consumption.