7℃ chilled water flows into the cooling coils and makes the coil surface cold. The fan inside the unit draws ambient warm and humid air through the coils, thus the air is cooled below the dew point: the temperature is lowered, and the moisture is removed.

The water condenses on the coil surface and drips into the condensate pan directly.

Through this heat exchange process, the return water inside the coil will increase to 12℃ and return to the water tank. The off-coil air will be around 13℃, with 95% relative humidity, and with a moisture content of 8g/kg. The unit keeps working to keep the space with the constant moisture content.