Vertiv Liebert HPC-M Serie Manuel De Service page 7

Fig. b --- Ideal chilled water circuit
10a 10b 10c
Fig. c --- Inertial tank sizing
The total optimal hydraulic value of the system where the Liebert HPC- - M chiller is installed can be calculated
by the following ratio:
V =
where:
- - V=min. required total water volume expressed in liters
- - Rt=refrigerating capacity expressed in kW
- - Xd=differential band set on the control and expressed in degrees centigrade
Please note that the min. required total water volume (V) must be at least equal to the sum of the hydraulic
volume of the Liebert HPC- - M chiller (Vm) plus the volume of the hydraulic circuit connected to it (Vpc); if
this condition is not complied with, it is necessary to install an inertial tank (Vpt, as indicated in the Fig. b ideal
chilled water circuit) with a volume at least equal to the following value: Vpt=V- - Vm- - Vpc
Fig. d --- Sizing of the expansion tank
The total volume of the expansion tank is calculated with the following ratio:
C x e
V =
Pi
1 - -
Pf
where:
- - C=quantity of water inside the system expressed in liters
- - e=water expansion coefficient, with water at 10
- - Pi=absolute pressure of initial charging, equivalent to the tank pre- - charge pressure (typical value
2.5 bara)
- - Pf=absolute final tolerated pressure, lower than the operating pressure or than the safety valve
calibration pressure (typical value 4.0 bara).
Use the values of the water expansion coefficient indicated in the table below:
4
discoonnect
after charge
9
10e
10d
12
43 x Rt
Xd
1 6 3 4 7
T
5
Vpt
Tank
USER
1
o
C as a reference
English
2 3
CHILLER
5 5
1 11
4 1
8
T