Anti-Condensation Measures - Siemens SINAMICS S120 Equipment Manual

Cabinet Design and EMC
12.7 Cooling
12.7.3

Anti-Condensation Measures

Special measures must be taken to prevent condensation.
Condensation occurs when the inlet temperature of the cooling medium is significantly
lower than room temperature (ambient temperature).
The table below shows the dew points (in °C) for an atmospheric pressure of 1 bar
(≈ installation altitude: 0...500 m). If the temperature of the cooling medium is below the
specified value, condensation may occur (i.e. the temperature of the cooling medium
must always be ≧ the dew point temperature).
Table 12-15 Dew point temperature as a function of the relative air humidity (Φ) and the room temperature at an
installation altitude of between 0 m and 500 m
T room Φ=20% Φ=30%
°C
10 <0 <0
20 <0 2
25 0.6 6.3
30 4.7 10.5
35 8.7 14.8
38 11.1 17.4
40 12.8 19.1
45 16.8 23.3
50 20.8 27.5
The dew point also depends on the absolute pressure (i.e. the installation altitude).
Various measures can be taken to prevent condensation:
1. Temperature-controlled valves in the supply line.
2. Water temperature control.
3. Physical dehumidification.
4. Installing a heater with a sufficient capacity in the cabinet.
To prevent condensation, a humidity detector can be used to monitor the air humidity. The
humidity detector is not included in the scope of supply.
12-34
Φ=40% Φ=50%
<0 0.2
6 9.3
10.5 13.8
14.9 18.4
19.3 22.9
22 25.7
23.7 27.5
28.2 32
32.6 36.6
In the cooling circuit, a temperature-controlled valve must be provided in the supply line.
The water temperature is adjusted in line with the room temperature. This is the preferred
method with high room temperatures, low water temperatures, and high air humidity.
This is only effective in closed spaces. This method involves condensing the air humidity
in an air-to-water heat exchanger, which is continuously operated using the cold cooling
water.
Φ=60% Φ=70% Φ=80%
2.7 4.8 6.7
12 14.3 16.4
16.7 19.1 21.2
21.3 23.8 26.1
26 28.6 30.9
28.8 31.5 33.8
30.6 33.4 35.8
35.3 38.1 40.6
40 42.9 45.5
Equipment Manual Booksize Cold-Plate Power Sections
Manual, (GH4), Edition 06.2005, 6SL3097-2AJ00-0BP2
Φ=85% Φ=90% Φ=90%
7.6 8.4 9.2
17.4 18.3 19.1
22.2 23.2 24.1
27.1 28.1 29
32 33 34
34.9 36 36.9
36.9 37.9 38.9
41.8 42.9 43.9
46.6 47.8 48.9
Φ=100%
10
20
24.9
29.9
34.9
37.9
39.9
44.9
49.9