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 drive 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 speed. 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 speed. The
consumption of energy, however, is reduced by 50%.
42
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 © 12/2018 All rights reserved.
®
DriveMotor FCP 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 speed.
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 drive solution offers major savings compared
with traditional energy-saving solutions. This is because the
drive is able to control fan speed according to thermal
load on the system and the fact that the drive has a built-
in facility that enables the drive 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,
for example to 60%. Energy savings of more than 50% can
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%
MG03M302