Danfoss PTU 025 Design Guide

130BA780.11
SYSTEM CURVE
FAN CURVE
PRESSURE %
A
B
C
0
20
40
60
80
100
120
20 40 60 80 100 120 140 160 180
VOLUME %
Illustration 5.8 Fan Curves for Reduced Fan Volumes.
Example of energy savings
Illustration 5.9 describes the dependence of ow, pressure,
and power consumption on RPM. As seen in Illustration 5.9,
the ow is controlled by changing the RPM. Reducing the
speed only 20% from the rated speed also reduces the
ow by 20%. The ow is directly proportional to the RPM.
The consumption of electricity, however, is reduced by
50%.
If the system only runs at 100% ow a few days per year,
while the average is below 80% of the rated ow, the
amount of energy saved is even more than 50%.
Flow:
Q
1
Q
2
 = 
n
1
n
2
Pressure:
H
1
H
2
 = 
n
1
n
2
2
Power:
P
1
P
2
 = 
n
1
n
2
3
Q Flow P Power
Q
1
Rated ow P
1
Rated power
Q
2
Reduced ow P
2
Reduced power
H Pressure n Speed control
H
1
Rated pressure n
1
Rated speed
H
2
Reduced pressure n
2
Reduced speed
Table 5.1 Laws of Proportionality Denitions
n
100%
50%
25%
12,5%
50% 100%
80%
80%
175HA208.10
Power ~n
3
Pressure ~n
2
Flow ~n
Illustration 5.9 Laws of Proportionality
Comparison of energy savings
The Danfoss drive solution
oers major savings compared
with traditional energy saving solutions. The drive
regulates fan speed according to thermal load on the
system and functions as a building management system
(BMS).
The graph (Illustration 5.10) shows typical energy savings
obtainable with 3 well-known solutions when fan volume
is reduced to 60%. As the graph shows, more than 50%
energy savings can be achieved in typical applications.
130BA779.12
0 60 0 60 0 60
0
20
40
60
80
100
Discharge Damper Solution
IGV Solution
VLT Solution
Energy consumed
Energy consumed
Energy consumed
Input power %
Volume %
Illustration 5.10 3 Common Energy Saving Systems
Discharge dampers reduce power consumption. Inlet guide
vanes oer a 40% reduction but are expensive to install.
The Danfoss drive solution reduces energy consumption by
more than 50% and is easy to install.
Product Features Design Guide
MG16C302 Danfoss A/S © 11/2017 All rights reserved. 27
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Danfoss PTU 025 Specifications

General

Brand	Danfoss
Model	PTU 025
Category	DC Drives
Language	English