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[Note 1]
Each item of the standard values may cause the failure due to corrosion
or scale and if any item deviates from the standard value, it is assumed
that corrosion or scale tends to be caused, therefore, these should be periodically managed.
[Note 2]
As the range of the water quality which may become usable if the water is processed
differs depending on the chemicals to be used, it is not given here. It is desirable to set
the appropriate water quality management values under the guidance of a water processing
specialist and periodically manage the water quality.
(2) Typical water treatment
Even if make-up water for cooling water agrees with water standards, the water quality gets
worse by its concentration, therefore the following water treatment is necessary. To varying
extent of deterioration, chilled/hot water also requires this treatment.
In case you use concrete heat storage tank, special attention should be paid to water
treatment.
a) Periodic and continuous manual blow down by make-up water
b) Automatic blow down by electric conductance
c) Addition of the anticorrosion
d) Slime control
e) Periodic water analysis
Overhaul water header periodically, check heat transfer tube and clean it as
necessary.
1
2
3
Fouling factor (m
1
2
Fouling factor (m
0.2 0.4 0.6 0.8 1.0 1.2
Scale/Slime(mm)
Fig.4-3 Example of effect by fouling of tube
4 5 6
7
8
9 10
・hr・℃/kcal)×10
2
3
4
5
6
7
8
・℃/kw)×10
-4
2
For example, if 0.6mm of scale clings
to tube, cooling capacity drops to
76%, and chilled water temperature
rises by 2℃ and fuel consumption
rises by 23%.
In case of constant cooling capacity
A
(Ratio at rated fuel consumption)
Rise in fuel consumption
B
Lowering of cooling capacity
C
(In case of constant chilled water
temperature)
Rise in chilled water temperature
D
-4
(In case of constant cooling
9
capacity)
48
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