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4.4.4 Supply air humidification 4
load mode
The 4-load-configuration allows for exact
humidification controllability even in the
range of minimum output demand.
A prerequisite for this mode of operation is
the availability of 4 independant nozzle sec-
tions. For controlling the supply air humidifi-
cation, an on-site control signal of 0...10 V
(0...20 mA / 0...140
Ω
) is required that is
transformed to an internal actuator signal.
In the range up to approximately 12.5 percent
of the actuator signal (switching point 1), only
one nozzle section is driven with an atomisa-
tion pressure of 25...75 bar, the so called „1
st
load“. Beyond that level,the pumping sta-
tion switches on the second nozzle section
and reduces the pressure to 25 bar. Following
this, with rising humidification demand, up to
approxomately 25% of the actuator signal, the
atomisation pressure is proportionally in-
creased up to the maximum of 75 bar („2
nd
load“).
Beyond this, the third nozzle section is
switched on („3
rd
load“) while the pressure is
decreased to 25 bar again. The further in-
crease of the actuator signal up to approxi-
mately 50%, the atomisation pressure is
proportionally increased to 75 bar.
Beyond the 50 percent, the fourth nozzle
stage is also switched on („4
th
load“) and the
atomisation pressure is reduced again to 25
bar. With the control signal now rising up to
100 percent, the atomisation pressure rises to
75 bar and the system reaches maximum
possible humidification output.
4.4.5 Exhaust air cooling
The high-pressure nozzle system was either
ordered as an exhaust cooling system or can
be put to exhaust air cooling operation mode
by (switched) wiring, when a combined sy-
stem was ordered (s. section 4.4.6). As a
control signal, the whole variety is available
that is possible for the control supply air humi-
dification mode. In contrast to the supply air
humidification mode, exhaust air cooling com-
prises no load swiching.
The purpose of the extract air cooling is to
transfer maximum cooling capability into the
supply air flow (heat exchanger provided by
customer), to support air conditioning
systems. In this type of application
humidification is typically 95 to 100 percent.
All nozzles are immediately supplied with
maximum power when the system is enabled.
If the humidity switch or another sensor
detects that cooling is no longer necessary
the enabling is cancelled and the system goes
to stand-by mode.
4.4.6 Combined system
A combined system allows for switching bet-
ween supply air humidification and exhaust
air cooling. Supply air humidification can be
run in the „Standard“, „2-load“ and „3-load“
modes with the full variety of control signals
that are supported by a dedicated system.
When exhaust air cooling is selected, how-
ever, only 1-step operation is possible.
