Air movement - quite similar
to the movements which we know from the weather around us - occur also in any closed space
which is not totally isolated from the outside - e.g. in a glasshouse, a wintergarden, in
a cold storage space, in a conference room, but also inside the cabinet of an electronic device.
If the climatic conditions of the closed space
is changed with regards to the "outside" - e.g. by means of heating, cooling, humidification
or desiccation - a local "micro-climate" will be created.
is not only influenced by the artificial processes which are installed, but also by outside
influences like sunlight, insulation or intake of fresh air.
According to the intended use of the space the
responsible person will try to create an optimal micro-climate which is beneficial for the
"inhabitants" (plants, animals, mushrooms, stored goods).
In case it is necessary
to humidify the air - by means of a fogging system - a natural air circulation will occur.
Everybody knows that hot air has a lower specific
weight than cold air.
Hot air will rise up (thermic lift), cold air will fall down.
Furthermore we know that hot air can take up more water vapour as well as that hot, unsaturated
air will cool down by evaporating fog droplets.
With most fogging systems the feeder-pipes together
with the fogging nozzles are mounted in the upper parts of the treated space..
the application of fog the temperature of the surrounding air will cool down by adiabatic
cooling and will sink downwards.
It will replace the warmer air layers which have been
located so far near the floor which will rise towards the ceiling. Usually a rotating air
current will be formed after a short while - parallel to the feeder pipes carrying the nozzles.
The rotation will be faster, if the treated air layers are hot and dry and slower if the
air is already cool and humid (as e.g. in a cold storage).
Therefore the air movement is NOT induced by
larger or smaller water droplets entering the air, but alone by the cooled air layers which
will sink down !