13 Further technical information
EN
30
Rittal Liquid Cooling Package
13
Further technical information
13.1 Hydrological information
To avoid damages to the system and ensure reliable op-
eration, the provisions of VDI 2035 should be observed
for filling and top-up water.
Admissible cooling media
– Saline and low-salinity water based on VDI 2035 plus
max. 50 volume percent Antifrogen-N (see table 6).
Recommended cooling medium
– Low-salinity water (demineralised water) based on VDI
2035. Up to a maximum of 50 volume percent Antifro-
gen-N may be added (see table 6).
13.2 Characteristic curves and tables
13.2.1 General
All information in the following tables refers to the use of
pure water as a cooling medium. The cooling perfor-
mance data when using a water-glycol mixture is availa-
ble on request from Rittal.
Proceed as follows to determine the required cooling
water temperature:
Determine the dew point for the room temperature
and relative humidity in the room (see section 13.2.2
"Determination of the dew point"). Alternatively, you
can use the h-x diagram (fig. 2).
Determine the minimum admissible cooling water
temperature by adding a safety margin of 3°C to this
figure.
Determine the required water throughput and
achieved cooling efficiency for the required airside
temperature difference
T.
If the cooling efficiency determined in this way is 100%,
then the air outlet temperature from the LCP Hybrid will
be less than, or at the most, equal to the air inlet temper-
ature into the server enclosure.
If the cooling efficiency determined in this way is less
than 100%, then the air outlet temperature from the LCP
Hybrid will be greater than the air inlet temperature into
the server enclosure. The room temperature will rise ac-
cordingly over time.
13.2.2 Determination of the dew point
Determination of the dew point for room temperature
20°C
Determination of the dew point for room temperature
21°C
Determination of the dew point for room temperature
22°C
Low-salinity
Saline
Electrical conductiv-
ity at 25°C [μS/cm]
< 100
100…1,500
Appearance
Free from sedimenting substances
pH value at 25°C
8.2…10.0
Oxygen [mg/l]
< 0.1
< 0.02
Tab. 6:
Water specifications
Room tempera-
ture [°C/°F]
Rel. humidity
[%]
Dew point
[°C/°F]
20 / 68.0
40
6 / 42.8
20 / 68.0
45
7.7 / 45.9
20 / 68.0
50
9.3 / 48.7
20 / 68.0
55
10.7 / 51.3
20 / 68.0
60
12 / 53.6
Tab. 7:
Determination of the dew point for room temperature
20°C
Room tempera-
ture [°C/°F]
Rel. humidity
[%]
Dew point
[°C/°F]
21 / 69.8
40
6.9 / 44.4
21 / 69.8
45
8.6 / 47.5
21 / 69.8
50
10.2 / 50.4
21 / 69.8
55
11.6 / 52.9
21 / 69.8
60
12.9 / 55.2
Tab. 8:
Determination of the dew point for room temperature
21°C
Room tempera-
ture [°C/°F]
Rel. humidity
[%]
Dew point
[°C/°F]
22 / 71.6
40
7.8 / 46
22 / 71.6
45
9.5 / 49.1
22 / 71.6
50
11.1 / 52
22 / 71.6
55
12.5 / 54.5
22 / 71.6
60
13.9 / 57
Tab. 9:
Determination of the dew point for room temperature
22°C
