INTRODUCTION
NOTE:
Prior to installing any AIRFOG product
carefully READ through this entire guide, it contains
valuable information which will assist in all aspects of
the installation.
AIRFOG DEFINITION
NORTEC AIRFOG systems use the nozzle
humidification technology of injecting droplets of cold
water directly into the air. This method of
humidification has the following advantages over
steam humidification:
·
Lower frequency of maintenance.
·
Systems are mainly mechanical (water pipes
and air pressure) with only a 24 Vac power
requirement in the control panel.
·
A “no cost” air cooling benefit due to latent
heat of vaporization extracting heat from the
air.
·
Maintenance is primarily focused on keeping
the air compressor operational.
·
Change of components is fast and requires
minimal system disassembly.
NORTEC AIRFOG FAMILY OF PRODUCTS
Axair Nortec manufactures AIRFOG products in
two groups. The first group is modular systems that
require engineering design and component assembly
while the second group is self contained. Both groups
require connection to electrical power, water and
compressed air.
The modular systems group consists of two
families of humidifiers:
·
AFE (AIRFOG Economical) Systems use subsonic
air flows and commonly used in space.
Prepackaged self contained group consists of two
families of humidifiers:
·
AFE Mini Systems are wall mounted with 1 or 2
nozzles.
·
AFE OCTO Systems are ceiling mounted with fog
injection from two sides (dual configuration) from a
rectangular case using 4, 6 or 8 AFE nozzles or as
wall mounted with injection from one side (single
configuration) using 3 or 4 AFE nozzles. AFE
OCTO systems are available with or without a
AFE Control Panel built into the case. AFE OCTO
systems are available for use with normal tap
water, reverse osmosis or de-ionized (DI) water.
PRINCIPLE OF OPERATION AFE SYSTEM
The AFE nozzle uses air flow (based on Bernoulli
principle) to siphon water out of zero psig water
distribution pipes. Increases in air velocity (by
increasing air pressure) will increase the vacuum
pressure and hence more water is siphoned into the
nozzle. As the water exits the nozzle it is broken down
into a fine mist by a shearing action. Increases in air
supply pressure also means that the exiting mixed flow
is at a higher velocity.
Since AFE nozzle systems use a zero psig water
pressure feed network, the water feed system and
nozzles must be horizontal and at the same height as
the water pressure reduction regulator (Vacuum
Valve). Valleys or dips in altitude will adversely affect
performance and in extreme cases will prevent the
nozzles from producing any output. If obstructions
prevent straight level piping, the water and air network
delivery pipes must be routed under the obstruction. It
is vital that the water pipes, downstream of the
Vacuum Valve, never be elevated higher than the
nozzles. The Vacuum Valve must also be at the same
height as the nozzles.
GENERAL AIRFOG TECHNICAL
CONSIDERATIONS
ADIABATIC COOLING PHENOMENA
There are no heating elements in any of
NORTEC’s AIRFOG humidifiers. Water is injected
directly into the air at the temperature it is supplied.
As the droplets evaporate they extract the required
latent heat of vaporization from the surrounding air
which causes the temperature of the air to decrease.
This could be a significant energy saving technique if
mechanical cooling is required. Since humidification is
most often required when the exterior atmospheric
temperature is below room temperature, there is a
necessity to warm the air either prior to addition of the
water droplets or after absorption of the droplets into
the air. It is recommended to add the moisture after
the air is heated as this dramatically reduces the time
and distance taken for the water droplets to evaporate.
ZONES FOR SPACE APPLICATIONS
Humidity variation can be controlled in a tight
fashion by sealing the zone with air tight structures or
the humidity can be controlled on a more global sense
in a large factory volume. There are some situations
where it makes more sense to control the humidity in a
multiple floored structure using a separate system.
Relative humidity will rapidly equalize with adjoining
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