The laws of proportionality
This figure describes the dependence of flow, pres-
sure and power consumption on rpm.
Q = Flow
P = Power
Q
1
= Rated flow
P
1
= Rated power
Q
2
= Reduced flow
P
2
= Reduced power
H = Pressure
n = Speed regulation
H
1
= Rated pressure
n
1
= Rated speed
H
2
= Reduced pressure
n
2
= Reduced speed
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
Example with varying flow over 1 year
The example below is calculated on the basis of pump characteristics obtained from a pump datasheet. (45 kW).
The same examples of calculations can be used in the case of fan characteristics.
The result obtained is savings in excees of 50% at the
given flow distribution over a year, corresponding to 8,760 hours.
Typically, the example calculated below results in a pay-back period of one year - depending on the price per kWh
and the price of the frequency converter.
Pump characteristics
Energy savings
This figure compares power control via valves and
without speed control with pressure control via a fre-
quency converter.
P
shaft
=P
shaft output
Flow distribution over 1 year
VLT
®
6000 HVAC Series
10
MG.61.B5.02 - VLT
®
is a registered Danfoss trademark
Содержание VLT 6000 HVAC Series
Страница 31: ...Ordering form VLT 6000 HVAC Series MG 61 B5 02 VLT is a registered Danfoss trademark 31 Introduction to HVAC ...
Страница 63: ...Mechanical dimensions VLT 6000 HVAC Series MG 61 B5 02 VLT is a registered Danfoss trademark 63 Installation ...
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