Example Of Energy Savings; Comparison Of Energy Savings - Danfoss VLT DriveMotor FCP 106 Design Manual

Application Examples
100
80
60
40
4 4 20
0 20
Illustration 4.5 The Graph Shows Fan Curves (A, B, and C) for
Reduced Fan Volumes
When using a frequency converter to reduce fan capacity
to 60%, more than 50% energy savings may be obtained in
typical applications.
120
100
80
60
40
20
0
20
120
100
80
60
40
ENERGY
20
CONSUMED
0 20
Illustration 4.6 Energy Savings at Reduced Fan Capacity

4.2.3 Example of Energy Savings

As shown in Illustration 4.7, the flow is controlled by
changing the RPM. By reducing the speed only 20% from
the rated speed, the flow is also reduced by 20%. This is
because the flow is directly proportional to the RPM. The
consumption of electricity, however, is reduced by 50%.
50
VLT
A
SYSTEM CURVE
FAN CURVE
B
C
40 60 80 100 120 140 160
VOLUME %
A
SYSTEM CURVE
FAN CURVE
B
C
40 60 80 100 120 140
Volume %
40 60 80 100 120 140
Volume %
Danfoss A/S © 06/2016 All rights reserved.
®
DriveMotor FCP 106/FCM 106
If a system only has to supply a flow that corresponds to
100% a few days in a year, while the average is below 80%
of the rated flow for the remainder of the year, the amount
of energy saved is even more than 50%.
Illustration 4.7 describes the dependence of flow, pressure,
and power consumption on RPM.
180 100%
80%
50%
25%
12,5%
Illustration 4.7 Laws of Proportionality
Q
Flow :
Q
160 180
Pressure :
Power :
Q=Flow
Q =Rated flow
1
Q =Reduced flow
2
H=Pressure
H =Rated pressure
1
H =Reduced pressure
2
Table 4.1 Legend for Equation

4.2.4 Comparison of Energy Savings

160 180
The Danfoss frequency converter solution offers major
savings compared with traditional energy-saving solutions.
This is because the frequency converter is able to control
fan speed according to thermal load on the system and
the fact that the frequency converter has a built-in facility
that enables the frequency converter to function as a
building management system, BMS.
Illustration 4.8 shows typical energy savings obtainable
with 3 well-known solutions when fan volume is reduced,
Flow ~n
Power ~n
50%
n
1 1
=
n
2 2
2
H n
1 1
=
H n
2 2
3
P n
1 1
=
P n
2 2
P=Power
P =Rated power
1
P =Reduced power
2
n=Speed control
n =Rated speed
1
n =Reduced speed
2
2
Pressure ~n
3
n
80% 100%
MG03M202