Procedure Of Cooling Circuit Configuration - Siemens SINAMICS G130 Engineering Manual

SINAMICS S120 Cabinet Modules
Engineering Information
such a level that the installed S120 Cabinet Modules can be operated within the specified pressure and volumetric
flow rate limits.
Pressure reduction by the ball valve is particularly important in cases where the volumetric flow rate required by the
S120 Cabinet Modules is significantly lower than the rated flow rate of the Heat Exchanger Module. This is because
the pressure drop at the heat exchanger of the Heat Exchanger Module is extremely low and practically all the
pressure generated by the pump constitutes a pressure difference between the inflow and return flow lines of the
deionized water circuit.
With a correctly dimensioned and calibrated cooling system, the typical temperature rise of the coolant in the
deionized water circuit between the inflow and return flow lines is approximately 6°C when the S120 Cabinet Modules
are operating under full load. The difference between the coolant temperature in the inflow line of the deionized water
circuit and the coolant temperature in the inflow line of the raw water circuit must be at least 7°C when the S120
Cabinet Modules are operating under full load.
7.3.4.6

Procedure of cooling circuit configuration

1. Calculating the required coolant temperature setpoint in the inflow line of the deionized water circuit
As a first step in configuring the cooling circuit, the minimum required setpoint T
inflow line of the deionized water circuit must be determined. This is because the coolant temperature in the inflow
line must always be higher than the dew point of the air in order to protect the power units in the S120 Cabinet
Modules against condensation. The dew point of the air T
ambient temperature T
max
Ambient
temperature
20 %
T
10 °C < 0 °C
20 °C < 0 °C
25 °C 0.6 °C
30 °C 4.7 °C
35 °C 8.7 °C
40 °C 12.8°C
45 °C 16.8°C
50 °C 20.8°C
Approximately 4°C must be added to the dew point T
temperature setpoint T in the inflow line of the deionized water circuit.
set
The calculated coolant temperature setpoint T
control system of the Heat Exchanger Module during commissioning. The control system uses the 3-way valve
(bypass valve) in the deionized water circuit of the Heat Exchanger Module to keep the setpoint constant.
2. Calculating the current derating factor of the power units required by the temperature conditions
The maximum predicted ambient temperature T
deionized water circuit (calculated above) must be within the permissible range of the relevant current derating
characteristics taking into account the degree of protection of the unit in question. If the characteristics are below
100 % for one or both of the temperatures, the relevant current derating factors must be applied when the electrical
dimensioning of all S120 Cabinet Modules is done.
Note:
The current derating factors of the two charts must not be multiplied. For dimensioning purposes, it is the least
favorable derating factor of the two charts that applies which means that a total derating factor of 0.9 is applicable
under worst-case conditions.
SINAMICS Engineering Manual – November 2015
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and the maximum predicted relative air humidity Φ
30 % 40 % 50 %
< 0 °C < 0 °C 0.2 °C
2.0 °C 6.0 °C 9.3 °C
6.3 °C 10.5°C 13.8°C
10.5°C 14.9°C 18.4°C
14.8°C 19.3°C 22.9°C
19.1°C 23.7°C 27.5°C
23.3°C 28.2°C 32.0°C
27.5°C 32.6°C 36.6°C
T = T (T and Φ according to table) + 4 °C
set dp max max
in the inflow line of the deionized water circuit must be set on the
set
and the coolant temperature setpoint T
max
is determined according to the maximum predicted
dp
as specified in the table.
max
Relative air humidity Φ
60 % 70 % 80 %
2.7 °C 4.8 °C 6.7 °C
12.0°C 14.3°C 16.4°C
16.7°C 19.1°C 21.2°C
21.3°C 23.8°C 26.1°C
26.0°C 28.6°C 30.9°C
30.6°C 33.4°C 35.8°C
35.3°C 38.1°C 40.6°C
40.0°C 42.9°C 45.5°C
as a safety margin in order to achieve the minimum coolant
dp
of the coolant temperature in the
set
85 % 90 % 95 %
7.6 °C 8.4 °C 9.2 °C
17.4°C 18.3°C 19.1°C
22.2°C 23.2°C 24.1°C
27.1°C 28.1°C 29.0°C
32.0°C 33.0°C 34.0°C
36.9°C 37.9°C 38.9°C
41.8°C 42.9°C 43.9°C
46.6°C 47.8°C 48.9°C
in the inflow line of the
set
100 %
10.0°C
20.0°C
24.9°C
29.9°C
34.9°C
39.9°C
44.9°C
49.9°C