Feature
Humidair | Condair
An example of a condensing de-humidifier . moisture from the air ). This equilibrium prevents loss or moisture absorption as temperature and ambient air moisture content changes . Without a stable RH , products could crack , warp , and deteriorate over time . Stability would be highly relevant in such facilities that produce chemicals that may react adversely outside of set parameters .
A common analogy in describing humidity , which is essentially the percentage of water as a vapour in any given space , is the concept of a cubed sponge that would be proportionately saturated based on the ideal gas law factors . “ At a specific temperature ( 25 degrees in summer ), that sponge could be 60 % full , while at 25 degrees in winter it could be 30 % full . As contraction and expansion of air occurs , the volume either gets smaller or increases . You can then imagine the level of moisture in that sponge changing . As RH increases it will eventually reach saturation known as the dew point – the air has cooled down to the point where the water inside the air is at 100 %. It has got nowhere else to go and so results in condensation ,” explains John Andersen , director at Specialised Climate Engineering .
In a data centre as another example or a server room in a bank , engineers are looking at a ‘ dynamic window ’ or ideal range where
The ideal gas law describes the relationship between pressure , volume , and temperature in air . The reason why humidity control is required comes down to the nature of the expansion and contraction that occurs due to the changing conditions throughout the day , season , or climate conditions . Expansion and contraction thus create differences in RH and the difference in RH creates various impacts on spaces or materials that could be extremely sensitive to said changes .
“ The inclusion of the optimal band of humidity can be applied to almost any item , procedure or process to produce any goods we have access to today .”
“ Generally , a 50 % RH indoors is ideal for humans to feel comfortable and is also the lowest point in terms of ideal conditions for viruses and bacteria – too humid , and bacteria and mould growth may occur . If air is too dry , dust and static electricity becomes a risk which is not ideal in several settings ,” says Kotze .
RH maintains the equilibrium conditions around many hygroscopic materials ( product or substances that absorb
www . hvacronline . co . za RACA Journal I September 2021 35