Danfoss VLT HVAC Drive FC 102 Design Manual page 30

Product Features
Example with varying flow over 1 year
Illustration 5.11 is based on pump characteristics obtained from a pump datasheet. The result obtained shows energy
savings more than 50% at the given flow distribution over a year. The payback period depends on the price per kWh and
the price of the drive. In this example, it is less than a year when compared with valves and constant speed.
[h] t
2000
1500
1000
5 5
500
Illustration 5.11 Flow Distribution Over 1 Year
m 3 /h
350
300
250
200
150
100
Σ
Table 5.2 Energy Savings Calculation
28
100 200 300 400
Distribution
% Hours Power
A -B
1
5 438 42.5
15 1314 38.5
20 1752 35.0
20 1752 31.5
20 1752 28.0
20 1752 23.0
100 8760 –
Danfoss A/S © 11/2017 All rights reserved.
®
VLT HVAC Drive FC 102
Q
[m 3 /h]
Valve regulation
Consumption
kWh
1
18615
50589
61320
55188
49056
40296
275064
Drive control
Power Consumption
A -C kWh
1 1
42.5 18615
29.0 38106
18.5 32412
11.5 20148
6.5 11388
3.5 6132
– 26801
MG16C302