Danfoss VLT AQUA Drive FC 202 Design Guide

100% speed
Flow
Flow
Pump curve
Head or pressure Head or pressure
Natural
operating point
Operating
point
Throttled
Unthrottled
Throttled system
Unthrottled system
60
65
70
75
78
80
80
78
75
3
1
1
2
2
3
Hs
Hp
130BD890.10
1 Operating point using a throttle valve
2 Natural operating point
3 Operating point using speed control
Figure 2.3 Flow Reduction by Valve Control (Throttling)
Speed control
The same
ow can be adjusted by reducing the speed of
the pump, as shown in Figure 2.4. Reducing the speed
moves the pump curve down. The point of operation is
the new intersection point of the pump curve and the
system curve (3). The energy savings can be calculated by
applying the
anity laws as described in
chapter 2.1.3 Example of Energy Savings.
Flow
Head or Pressure
Pump curve
Operating
point
Natural
Operating point
system
Unthrottled
Speed
reduction
1
2
3
Hp
Hs
130BD894.10
1
Operating point using a throttle valve
2 Natural operating point
3 Operating point using speed control
Figure 2.4 Flow Reduction by Speed Control
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0 10 20 30 40 50 60 70 80 90 100
Recirculation
Throttle
control
Cycle
control
VSD
control
Ideal pump
control
Q(%)
P(%)
130BD892.10
Figure 2.5 Comparative Flow Control Curves
2.1.5
Example with Varying Flow over 1
Year
This example is calculated based on pump characteristics
obtained from a pump datasheet, shown in Figure 2.7.
The result obtained shows energy savings in excess of 50%
at the given ow distribution over a year,
see Figure 2.6. The payback period depends on the price of
electricity and the price of the adjustable frequency drive.
In this example, payback is less than a year, when
compared with valves and constant speed.
Product Overview
Design Guide
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Danfoss VLT AQUA Drive FC 202 Specifications

General

Brand	Danfoss
Model	VLT AQUA Drive FC 202
Category	DC Drives
Language	English