AERMEC Multichiller, Руководство пользователя

Страница: 23 / 40

23
Prg
Esc
Prg
Esc
SUW
SIW
PRIMARIO SECONDARIO
Disconnettore
Adjustment logics
Two adjustment logics can be used,
one for optimisation of the temperatu-
re of the plant (Temperature) and one
for optimisation of plant production
(Load). These logics are used to give a
chiller switch-on request condition and
a chiller switch-off request condition.
When a chiller is on it works autono-
mously with the steps (chokes or com-
pressors) that are available on the basis
of the adjustment and the setting. The
logic envisions that a chiller is always left working, it eventually switches-off
autonomously due to the thermostat.
On the basis of the adjustment logic,
the Multichiller increases or decreases
the number of chillers switched on.
Load adjustment: LOAD
Probe position: both of the probes must be positioned on the primary
circuit, before the disconnecting device, SUW on evaporator delivery
collector, SIW on the return entry to the chillers.
Plant features: management is optimised for plants where each chiller
controls its own pump (on/off together with the chiller) and with
secondaries with variable flow in the basis of the load.
If these features are not present, it is recommended to use
Homogeneous Mode for management of the chiller
The power of the chillers switched-on is calcula-
ted with this system, taking into consideration the
temperature differential between SIW and SUW
compared with the chiller full load Delta para-
meter that represents the DT between evaporator
water input and output of a chiller at full power
(parameter to be set in the basis of the project
conditions). In this way, the choke level of the
chillers switched-on is evaluated (% LOAD).
Conditions for switching-on a new chiller: when
the % LOAD value calculated is greater than the
% parameter, Load to start next.
Conditions for switching-off the next chiller:
when the envisioned % LOAD value that the chil-
lers currently switched-on will have, -1 is lower
than the % parameter Load chiller to stop next.
Examples are given below (with 3-chiller plant)
for the management of chillers in the three modes
sequential, homogeneous and combined