Danfoss VLT AQUA Design Manual page 17

®
VLT AQUA Drive Design Guide
2.7.4. Example with varying flow over 1 year
The example below is calculated on the basis of pump characteristics ob-
tained from a pump datasheet.
The result obtained shows energy savings in excess of 50% at the given
flow distribution over a year. The pay back period depends on the price
per kwh and price of frequency converter. In this example it is less than
a year when compared with valves and constant speed.
Flow
Pressure
Power
Energy savings
P
Flow distribution over 1 year
®
MG.20.N3.02 - VLT is a registered Danfoss trademark
2. Introduction to VLT AQUA Drive
Q n
1 1
: =
Q n
2 2
( )
H n 2
1 1
: =
H n
2 2
( )
P n
3
1 1
: =
P n
2 2
=P
shaft shaft output
2
17