Variable Flow Evaporator; System Minimum Water Volume; Evaporator Pressure Drop Curves; Condenser Pressure Drop Curves - Carrier 30XW-PZE Series Installation, Operation And Maintenance Instructions

6 - APPLICATION DATA

6.7 - Variable flow evaporator

Variable evaporator flow can be used. The pump drive can be
managed by unit control (0/10V output on terminal 90+ / 90-) The
controlled 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 liters of water per kW instead of 3.25 l/kW.

6.8 - System minimum water volume

Whichever the system, the water loop minimum volume is given
by the formula:
Volume = Cap (kW) x N litres
Application
Normal air conditioning
Process type cooling
where Cap is the nominal system cooling capacity (kW) at the
nominal operating conditions of the installation.
This volume is necessary for stable operation. 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.
Conection to buffer tank
Bad
Bad

6.9 - Evaporator pressure drop curves

Units with two evaporator passes (standard):
30XW-PZE / 30XWHPZE
1
120
110
100
90
80
70
60
50
40
30
20
10
0 10 20 30 40
Water flow rate, l/s
Legend
1 301
2 401, 451
3 551, 601, 651
N
3,25
6,5
Good
Good
3
2 4 5
50 60 70 80 90 100 110 120
4 801, 901
5 1001, 1101
Units with one evaporator pass (option 100C):
30XW-PZE / 30XWHPZE
36
33
30
27
24
21
18
15
12
9
6
3
0 10 20 30 40
Water flow rate, l/s
Legend
1 301
2 401, 451
3 551, 601, 651

6.10 - Condenser pressure drop curves

Units with two condenser passes (standard):
30XW-PZE / 30XWHPZE
1
120
110
100
90
80
70
60
50
40
30
20
10
0 10 20 30 40 50 60 70 80 90 100 110 120
Water flow rate, l/s
Legend
1 301
2 401, 451
3 551, 601, 651
Units with one condenser pass (option 100C):
30XW-PZE / 30XWHPZE
1
36
33
30
27
24
21
18
15
12
9
6
3
0 10 20 30 40
Water flow rate, l/s
Legend
1 301
2 401, 451
3 551, 601, 651
1 2 3 4
50 60 70 80 90 100 110 120
4 801, 901
5 1001, 1101
2 3 4
4 801, 901
5 1001, 1101
2 3 4 5
50 60 70 80 90 100 110
4 801, 901
5 1001, 1101
5
5
19