Professional Design





Humidity Build-up Control

What is humidity ?
Technically, humidity exists as relative humidity or absolute humidity. Relative humidity (RH) in % is the ratio of the actual amount of water vapor in the air to the amount it could hold when saturated . Absolute humidity (AH) in g/Kg of dry air is the mass of water vapor in a unit volume of air. It is a measure of the actual water vapor content of the air.
   Wet air enthalpy humidity figure  
  Its absolute humidity (AH)
The concern of humidity build-up is caused by too much increase in absolute humidity or moisture content. Eg: moisture content has increased from 20 g/Kg of dry air to 23.5 g/Kg of dry air when air is cooled from point A to point B. This increase is minimal but must be controlled. 
In a semi-enclosed or enclosed factory, moisture content can build-up. Therefore, the supply air must be exhausted by some form of mechanical means in order to keep the moisture content at minimum.

  Humidity control

  Refer to picture 1, if the air exhaust and supply is not balance, then the moisture content will be added up and result in humidity build-up.  
For picture 2, when exhaust and supply airflow can be controlled effectively then humidity build-up also can be controlled accordingly.

  Open Supply air naturally finds its way out.
    Semi-Enclosed Supply airs exit is limited. Mechanical exhaust is needed.
    Enclosed Supply airs exit is totally restricted. Mechanical exhaust is needed.