EN-
29
POWERCIAT LX ST/HE/XE
6.3 -
Maximum chilled water flow
(units without hydraulic module)
The maximum chilled water flow is shown in the table on the next
page. If the system flow exceeds the maximum value, it can be
bypassed as shown in the diagram.
For maximum chilled water flow rate
1
2
1 Evaporator
2 Bypass
6.4 -
Variable flow evaporator
A variable evaporator flow can be used in LX standard coolers.
The chillers maintain a constant leaving water temperature under
all flow conditions. For this to happen, the minimum flow rate
must be higher than the minimum flow given in the table of
permissible flow rates and must not vary by more than 10% per
minute.
If the flow rate changes more rapidly, the system should contain
a minimum of 6.5 litres of water per kW instead of 3.25 l/kW.
6.5 - Minimum system water volume
Whichever the system, the water loop minimum capacity is given
by the formula:
Capacity = Cap (kW) x N litres
Application
N
Normal air conditioning
3,25
Process type cooling
6,5
Where Cap is the nominal system cooling capacity (kW) at the
nominal operating conditions of the installation.
This volume is necessary for stable operation and accurate
temperature control.
It is often necessary to add a buffer water tank to the circuit in
order to achieve the required volume. The tank must itself be
internally baffled in order to ensure proper mixing of the liquid
(water or brine). Refer to the examples below.
Connection to a buffer tank
Incorrect
Incorrect
Correct
Correct
6.6 - Maximum system water volume
Units with hydraulic module incorporate an expansion tank that
limits the water volume. Maximum water loop volume (litres)
If the maximum volume is insufficient, compared to the minimum
system water loop volume, an additional expansion tank must
be added to the system.
LX ST/HE/XE
Sizes 0808 to 1358
1528
Static pressure
bar
1
2
2,5
1
2
2,5
Pure water
l
2400
1600
1200
3960
2640
1980
10% EG
l
1800
1200
900
2940
1960
1470
20% EG
l
1320
880
660
2100
1400
1050
30% EG
l
1080
720
540
1740
1160
870
40% EG
l
900
600
450
1500
1000
750
EG :
Ethylene Glycol
6.7 -
Evaporator water flow rate
LX ST/HE/XE
Minimum flow rate
(1)
(l/s)
Maximum flow rate
(2)
(l/s)
0808
3,6
37,5
0908
4,0
40,5
1008
4,3
40,5
1108
5,3
34,1
1358
6,0
36,9
1528
6,7
42,0
1858
8,1
45,0
2008
8,9
56,1
2158
9,6
59,1
2308
10,4
67,1
2528
11,0
67,1
2628
11,8
73,9
3028
13,1
83,9
3428
15,1
87,8
3828
16,4
126,5
4008
17,5
92,9
4408
16,4
132,1
4608
18,8
107,4
(1) Minimum flow rate for maximum allowable water temperature difference
conditions (10K) under Eurovent conditions
(2) Maximum flow rate for a pressure drop of 100 kPa in the plate heat exchanger
6 - APPLICATION DATA
