What is the difference between wet-coil and dry-coil control?

What is the difference between wet-coil and dry-coil control?

• A. Wet-coil control accounts for latent heat only; dry-coil control accounts for sensible heat only.
• B. Wet-coil control uses water; dry-coil control uses refrigerant.
• C. Wet-coil control accounts for sensible heat only; dry-coil control accounts for latent heat only.
• D. Wet-coil control accounts for both sensible and latent heat, while dry-coil control accounts for only sensible heat.

Answer: (D)

The main idea is how the coil handles moisture as well as temperature. A wet-coil control uses a cooling coil cooled below the air’s dew point, so moisture condenses on the coil. That condensation removes latent heat (moisture) in addition to lowering the air temperature, so both sensible and latent heat are addressed. A dry-coil control keeps the coil surface above the dew point, so no condensation occurs; only sensible cooling happens and humidity is not significantly changed. So wet-coil control accounts for both sensible and latent heat, while dry-coil control accounts for only sensible heat.

The main idea is how the coil handles moisture as well as temperature. A wet-coil control uses a cooling coil cooled below the air’s dew point, so moisture condenses on the coil. That condensation removes latent heat (moisture) in addition to lowering the air temperature, so both sensible and latent heat are addressed. A dry-coil control keeps the coil surface above the dew point, so no condensation occurs; only sensible cooling happens and humidity is not significantly changed. So wet-coil control accounts for both sensible and latent heat, while dry-coil control accounts for only sensible heat.