What is the Difference Between a Dry Coil and a Wet Coil

What is the Difference Between a Dry Coil and a Wet Coil

Dry Coil: A heat transfer coil that exchanges sensible heat (temperature change only, no moisture gain or loss) with the air outside the coil only through the fluid inside the coil (usually cold or hot water). When air flows through a dry coil, water does not precipitate as the temperature drops below the dew point, so the surface remains dry.

Wet Coil: When the temperature of the fluid inside the tube is lower than the dew point temperature of the air, the heat exchanger coil exchanges sensible heat and latent heat with the air simultaneously (the air is both cooled and dehumidified). When air flows through, moisture condenses and precipitates on the surface of the coil, leaving the surface in a wet state.

Functions and Applications of Dry Coil

Core Function: Pure temperature regulation (e.g., cooling the air with cold water in summer, warming the air with hot water in winter) without affecting the air humidity.

Typical scenarios:

Temperature and humidity independent control system: with the new air dehumidification system, dry coil is responsible for dealing with indoor sensible heat (such as computer rooms, precision laboratories, need to strictly control the temperature, but humidity by the new air system alone);

Radiant air-conditioning auxiliary: in the radiant refrigeration/heating system, dry coil as a supplement to quickly eliminate the indoor transient sensible heat load;

Clean environment: such as operating rooms, electronic clean room, to avoid the precipitation of the coil to breed mold, to protect the air cleanliness. Clean environment: such as operating room, electronic clean room, to avoid water precipitation of the coil, to avoid mold breeding, to ensure air cleanliness;

Winter heating: as a hot water coil, to heat the air (at this time the water temperature is higher than the dew point of the air, will not precipitate water, belongs to the dry coil mode of operation).

Functions and Applications of Wet Coil

Core Functions: Simultaneous cooling + dehumidification, core equipment for handling air heat and humidity load in conventional air conditioning systems.

Typical scenarios:

Ordinary comfort air conditioning: such as office buildings, shopping malls, residential, summer air temperature and humidity need to be reduced at the same time (to avoid sweltering);

high humidity dehumidification: such as the southern rainy season air conditioning system, through the wet coil to reduce the dew point of the air, to remove excess moisture;

process air conditioning: humidity requirements of the place (such as food workshop, printing workshop), the need for precise control of air temperature and humidity through the wet coil.