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8.5.4 Minimum chilled water flow
The minimum chilled water flow is shown in the table 8-8
If the system flow is less than the minimum unit flow rate,
the evaporator flow can be recirculated, as shown in the
diagram.
For minimum chilled water flow rate
UNIT
Fig. 8-30-1
8.5.5 Maximum chilled water flow
The maximum chilled water flow is limited by the
permitted pressure drop in the evaporator. It is provided
in the table 8-8
If the system flow is more than the maximum unit flow
rate, bypass the evaporator as shown in the diagram to
obtain a lower evaporator flow rate.
UNIT
Fig. 8-30-2
8.5.6 Minimum and Maximum water flow
Table 8-6
Item
Model
SCV-750EB
SCV-900EB
SCV-1400EB
SCV-1800EB
Recommendation
Fig.8-26 Design of the store tank
Recirculation
Recirculation
Waterflow rate(m
/h)
3
Minimum
Maximum
8
15.5
10.2
18
15.6
28.5
20.4
36.0
32
Error
8.5.7 Selection and installation of the pump
1) Select the pump
a) Select the water-flow of the pump
The rated water-flow must no less than the unit rated
water-flow; in terms of multi-connect the units, that
water-flow must no less than total units' rated water-flow.
b) Select the left of the pump.
H=h1+h2+h3+h4
H: The lift of the pump.
h1: Main unit water resistance.
h2: Pump water resistance.
h3: Water resistance of the longest water-loop distance,
includes:
pipe resistance, different valve's resistance, flexible pipe
resistance, pipe elbow and three-way resistance,
two-way resistance or three-way resistance, as well as
filter resistance.
H4: the longest terminal resistance.
2) Installation the pump
a) The pump should be installed at the water inlet pipe,
both of which sides must mount the soft connectors for
vibration-proof.
b) The backup pump for the system (recommended).
c) Units must with a main unit controls (Please see Fig.
8-18 for the controls wiring diagram).
8.5.8 Water quality
1) Water quality control
When industrial water is used as chilled water, little
furring may occur; however, well water or river water,
used as chilled water, may cause much sediment, such
as furring, sand, and so on.
Therefore, well water or river water must be filtered and
softened in softening water equipment before flowing
into chilled water system. If sand and clay settle in the
evaporator, circulation of chilled water may be blocked,
and thus leading to freezing accidents; if hardness of
chilled water is too high, furring may occur easily, and
the devices may be corroded. Therefore, the quality of
chilled water should be analyzed before being used,
such as PH value, conductivity, concentration of chloride
ion, concentration of sulfide ion, and so on.
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