16
C
B
20
15
10
5
0
-5
-10
-10
-5
0
5
10
15
50
45
40
35
30
25
D
5.6 - Variable flow evaporator
Variable evaporator flow can be used in standard chillers.
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
the values below.
5.7 - Evaporator flow rate
30RW
Minimum
flow rate, l/s
Maximum flow rate, l/s*
Maximum
flow rate, l/s**
Single pump
Dual pump
020
0.3
1.7
-
1.7
025
0.4
2.5
-
3.1
030
0.5
2.5
-
3.1
040
0.7
3.4
-
3.7
045
0.8
3.8
-
4.7
060
0.9
5.7
5.6
5.9
070
1.2
6.2
6.1
7.3
080
1.4
6.4
6.2
8.0
090
1.5
6.6
6.3
8.4
110
1.8
8.3
11.7
10.3
120
2.2
8.5
12.4
11.4
135
2.4
8.8
13.1
12.8
150
2.7
9.0
13.7
14.3
160
2.7
14.2
14.2
15.9
185
3.1
14.5
14.5
17.0
210
3.8
17.4
22.0
24.0
245
4.4
17.4
22.0
24.0
275
5.0
18.1
23.3
29.1
300
5.5
18.1
23.3
29.1
* Maximum flow rate for an available pressure of 50 kPa (unit with hydronic
module)
** Maximum flow rate for a pressure drop of 100 kPa in the plate heat exchanger
(unit without hydronic module)
5.8 - Condenser water flow rate (l/s)
30RW Minimum flow rate*
at min. condenser
capacity - ∆t = 10 k
Nom. condenser
flow rate at Eurovent
conditions
Maximum flow rate**
at max. condenser
capacity - ∆t = 5 k
020
0.5
1.2
1.4
025
0.7
1.5
1.8
030
0.8
1.7
2.0
040
1.0
2.3
2.7
045
1.2
2.7
3.1
060
1.4
3.3
3.8
070
1.8
4.1
4.8
080
2.1
4.7
5.5
090
2.3
5.4
6.2
110
2.8
6.4
7.4
120
3.3
7.3
8.5
135
3.6
8.3
9.5
150
4.0
9.1
10.3
160
4.2
9.4
10.9
185
4.7
10.8
12.5
210
5.7
12.7
14.6
245
6.5
14.5
16.8
275
7.3
16.6
19.0
300
8.0
18.2
20.5
* The minimum flow rate given is for units without hydronic module that have a
fixed condenser flow rate. Units with a hydronic module have a variable flow
rate and no minimum fixed flow rate. The minimum flow rate is optimised by
unit control in parallel with the drycooler fan stages for all operating conditions,
especially at low outdoor temperature and low load conditions.
** The maximum flow rate given is for units without hydronic module that have
a fixed condenser flow rate. Units with a hydronic module have a variable
flow rate. The maximum flow rate is optimised by unit control at all operating
conditions, based on pump capacity, system pressure losses and outdoor
temperature.
Notes 30RWA
1 Evaporator ∆T =5 K
2 Unit operation is limited by the maximum compressor condensing temperature
of 64°C.
A Standard unit operation with the anti-freeze solution required and special
control configuration.
B Operation at high air temperature is based on the condenser selected.
C Operating range down to 0°C, if the air-cooled condenser is not equipped with
a variable-speed head fan.
D Extended operating range with variable-speed fan.
5.4 - Minimum chilled water flow
If the system water flow rate is lower than the minimum
water flow rate, recirculation of the evaporator flow may
occur. The temperature of the mixture leaving the evaporator
must never be less than 2.8 K lower than the chilled water
entering temperature.
5.5 - Maximum chilled water flow
The maximum chilled water flow is limited by the maximum
permitted pressure drop in the evaporator. It is provided
in the table below. If the flow exceeds the maximum value,
two solutions are possible:
•
Modify the flow rate with the control valve.
•
Bypass the evaporator to obtain a highter temperature
difference with a lower evaporator flow rate.
Condensing temper
atur
e, °C
5.3 - Operating range 30RWA
Evaporator leaving water temperature, °C
Evaporator leaving water temperature, °C
Remote condenser entering air temper
atur
e, °C
60
55
50
45
40
35
30
-10
-5
0
5
10
15
64
A
