Data Sheet

3 - 43
Technical System Catalogue/Climate control
Air/water heat exchanger
Project planning
Calculate your required cooling output:
e. g. Performance diagram
Air/water heat exchanger 1000 W
Notes on water quality
For safe operation of the equipment, it is essential to observe
the VGB guidelines on cooling water (VGB-R 455 P).
The cooling water should have a low level of hardness, par-
ticularly calcium hardness. In particular, for recooling within
the plant, the calcium hardness should not be too high. On
the other hand, the water should not be so soft that it attacks
the materials. When recooling the cooling water, the salt con-
tent should not be allowed to increase excessively due to the
evaporation of large quantities of water, since electrical con-
ductivity increases as the concentration of dissolved sub-
stances rises, and the water thereby becomes more corro-
sive. For this reason, not only is it always necessary to add a
corresponding quantity of fresh water, but also to remove
part of the enriched water.
Water with high gypsum content is unsuitable for cooling pur-
poses because it has a tendency to form boiler scale that is
particularly difficult to remove. Furthermore, cooling water
should be free from iron and manganese, because other-
wise deposits may occur which settle in the pipes and block
them. At best, organic substances should only be present
in small quantities, because otherwise sludge deposits and
microbiological contamination may occur.
Material of the water-carrying parts
Hydrological data CuAl V4A
1)
pH value 7 – 8.5 6 – 9
Calcium hardness > 3 < 8° dH 1 – 12° dH
Free carbonic acid 8 – 15 mg/dm
3
1 – 100 mg/dm
3
Accompanying carbonic acid 8 – 15 mg/dm
3
Zero
Aggressive carbonic acid 0 mg/dm
3
0 – 400 mg/dm
3
Sulphides Zero Zero
Oxygen < 10 mg/dm
3
< 10 mg/dm
3
Chloride ions < 50 mg/dm
3
< 200 mg/dm
3
Sulphate ions < 250 mg/dm
3
< 500 mg/dm
3
Nitrates and nitrites < 10 mg/dm
3
< 100 mg/dm
3
COD < 7 mg/dm
3
< 40 mg/dm
3
Ammonia < 5 mg/dm
3
< 20 mg/dm
3
Iron < 0.2 mg/dm
3
Free
Manganese < 0.2 mg/dm
3
Free
Conductivity < 2200 μS/cm < 4000 μS/cm
Evaporation residue < 500 mg/dm
3
< 200 mg/dm
3
Potassium permanganate
consumption
< 25 mg/dm
3
< 40 mg/dm
3
Suspended matter
< 3 mg/dm
3
> 3 < 15 mg/dm
3
partial flow purification
recommended
> 15 mg/dm
3
continuous purification
recommended
1)
The complete absence of corrosion under experimental conditions suggests
that solutions with a significantly higher salt content and greater corrosion
potential (such as seawater) may still be tolerated.
50 Hz
SK 3373.100, .110, .140, .500, .510, .540
2800
3200
2400
2000
1600
1200
800
400
0
5101520253035
T
w
Q
K
.
25°C
35°C
45°C
T
i
V = 400 l/h
V = 200 l/h
T
W
= Water inlet temperature (°C)
Q
K
= Useful cooling output (W)
T
i
= Enclosure internal temperature (°C)
.
Water resistance performance diagram
SK 3373.100, .110, .140, .500, .510, .540
600
500
400
300
100
200
100 200 300 400 500
ΔP
V
.
V = Volumetric flow (l/h)
ΔP = Water resistance (mbar)
.