22
ENG
“optiMist” +0300065EN - rel. 1.6 - 18/06/2021
4. PUMPING UNITS
4.1 Pumping unit with flow control
configuration
optiMist controls the humidification and/or cooling capacity by
continuously controlling the atomised water flow-rate across a wide
range of modulation.
This configuration is used in the following applications:
•
humidification and/or evaporative cooling (direct) in an AHU;
•
humidification and indirect evaporative cooling in an AHU equipped
with a heat recovery unit (a single atomisation system atomises the
water).
optiMist is equipped with an inverter to continuously and precisely
control the speed of the pump and, consequently, the flow-rate.
The outlet pressure is kept within the optimum water atomisation limits
by the range of modulation of the pump speed and control of the
number of nozzles that atomise the water.
If the flow-rate required for humidification or evaporative cooling is small
then a few nozzles will be enough to atomise the water; if the request
increases, the increase in flow-rate will cause an increase in pressure that,
if it exceeds 15 bar, will activate other atomising nozzles (from the second
modulation step) with a subsequent decrease in the pressure, bringing it
within the optimum range.
Similarly, if the humidification request decreases, the flow-rate and thus
the pressure will decrease and, if the latter approaches 4 bars, some
nozzles will be closed so that the pressure returns within the optimum
atomisation range.
This is possible because the nozzles are assembled into groups of up to
four, with different capacities; when suitably activated, these guarantee
continuous modulation of the flow-rate across a wide range, nominally
from 40 or 20 at 100% (40% for pump 50, 100 and 200 l/h, 20% for 400,
800, 1000 l/h) the maximum flow-rate.
This is possible because the nozzles are combined together in groups up
to two nozzles with different capacities; this means that when activated,
they can guarantee continuous flow-rate modulation across a wide
range, nominally from 40 or 20 to 100% (20% for 50, 100 and 200 l/h
pumps, 40% for 400, 800, 1000 l/h) of maximum capacity.
