Cooling Circuit And Coolant Properties; Cooling Circuit Requirements; Technical Cooling Circuits - Siemens SINAMICS S120 Manual

Cooling circuit and coolant properties

13.1

Cooling circuit requirements

13.1.1

Technical cooling circuits

Technical cooling circuits can be divided into three systems:
● Closed cooling circuits (recommended)
In closed systems, the circuit coolant is separated from the surrounding atmosphere,
which prevents the ingress of oxygen. The coolant is only routed through SINAMICS
devices, the components required for cooling and, if necessary, a motor. The heat is
dissipated to the atmosphere indirectly by means of heat exchangers. The system should
ideally function without losing any coolant and, once filled, should not need any water to
be added. The composition of the coolant can be adjusted as required (e.g. by using
desalinated water and adding anti-corrosion agents). It either does not change at all
during operation, or changes only in a defined manner.
The closed cooling circuit is recommended as a standard solution.
● Open cooling circuit
The coolant is routed not only through the SINAMICS devices and components required
for cooling, but also through external devices.
The heat transferred to the circuit coolant evaporates via a cooling tower. This
evaporation causes the coolant to become more concentrated (densification) because
water molecules escape, while dissolved substances remain in the coolant. During
operation, therefore, the composition of the coolant changes significantly, which means
that it must be monitored and topped up continuously.
● Semi-open circuit
Oxygen can only enter the cooling system through the pressure equalization tank,
otherwise the same as a "closed cooling circuit". The semi-open cooling circuit is
permissible.
Booksize Power Units
Manual, (GH2), 07/2016, 6SL3097-4AC00-0BP8
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