Dehumidification Principles

Posted on: February 22nd, 2014 by Bruce Fontaine No Comments


The principles of Dehumidifying of air may be accomplished by three methods: Cooling – condensation of vapor, Adsorption of water and adsorption of water vapor.

1) In the cooling of air the humidity is reduced by cooling the air (via an evaporator coil or cooling coil) below dew point. The grains of moisture of the air is condensed on the coil and drained out by the condensate pan and condensate line. The efficiency of the coil or elimination of microbial growth on the heat transfer area (fins of the cooling coil or evaporator coil) will allow the air conditioning system to remove the ‘total heat content’ or Enthalpy & moisture in the air faster. This is accomplished by utilizing SMS’s ultra violet lighting system that will eliminate any microbial growth (bacterial & fungi) from growing on the fins of the coil. Thus, it allows the air that is going through the coil to be slower so that the air can be below due point and condense the moisture in the air faster.

2) Adsorption of water vapor is accomplished when the humidity is reduced by an adsorbent material such as silica gel or activated alumina. These systems are usually on chilled water systems and air handling units.

3) Absorption systems reduce the humidity with an absorbent material such as calcium chloride solution and it is generally not easy to reactivate the material. This system can be on packaged roof top units as well as air handling units.