140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
10
20
30
40
50
60
70
80
90
100
Recirculation
Throttle
control
Cycle
control
VSD
control
Ideal pump
control
Q(%)
P(%)
e
3
0
b
d
8
9
2
.1
0
Illustration 10: Comparative Flow Control Curves
4.3.3 Example with Varying Flow over 1 Year
This example is calculated based on pump characteristics obtained from a pump datasheet. The result obtained shows energy sav-
ings of more than 50% at the given flow distribution over a year. The payback period depends on the price per kWh and the price of
frequency converter. In this example, it is less than a year when compared with valves and constant speed.
Energy savings
P
shaft
= P
shaft output
500
[h]
t
1000
1500
2000
200
100
300
[m
3
/h]
400
Q
e
7
5
h
a
2
1
0
.1
1
Illustration 11: Flow Distribution over 1 Year
AJ300847815559en-000101 / 130R0337 | 25
Danfoss A/S © 2020.09
Product Family Overview
VLT® AQUA Drive FC 202
Design Guide