s
s
Increasing efficiency of key energy
consumption equipments
In this age of industrialisation, new and innovative
equipments are being designed and developed in order
to meet the increasing demand of industries. In addition,
a growing concern over environmental sustainability has
prompted companies to come up with solutions that have
the ability of produce sustainably.
Electrical and electronics industry is one such sector that
has been at the centre of attention from energy saving
point of view. Electricity is a key necessity for production
and other purposes as it is widely used to run indispensable
equipments like pumps, fans and compressors. Be it water
supply or water treatment, chemical or pharmaceutical
industry, or even production of mineral oil and plastics,
these equipments are required in the factories.
Government’s outlook towards energy
The Report of the Working Group on Power for 2012-17
highlights that during the last five years India has almost
fulfilled the dream of achieving the objective of “One Nation
One Grid. The Twelfth Five-Year Plan (2012-17) focused
largely on expanding the reach of electricity over the next few
years and also proposed a projected energy saving potential
of 11.43 mtoe1. The steps to reduce energy consumption
include reducing energy losses, owing to issues related to
harmonics, by way of installing various drives to provide
desired speed even when the power supply is low.
Energy efficient drive technology can not only help your
company save cost but also contributes hugely in protecting
the environment by using lesser energy. As industries, SMEs
and MSMEs together consume about 40-50 percent2 of
the total energy used in the country, the aim is to preserve
energy consumed by them.
How can VFD help?
A Variable Frequency Drive (VFD) is a type of motor
controller that has the ability of driving an electric motor
by altering the frequency and the voltage supplied to the
1
2
Report of The Working Group on Power for Twelfth Plan (2012-17), January 2012
Demand Side Management Energy Efficiency & Energy Conservation
Although the damper process changes the flow resistance, it
does not change the output power. The overall throttle loss
in this process is pretty high. In such cases, again, a VFD can
be an ideal solution.
While designing, the maximum predicted flow is taken
for calculation, so as to cater to adverse conditions. Then
the standard available pump/fan/compressor is selected.
Thereafter, the motor is selected to deliver the required
flow of equipment and finally drive is selected to suit motor
operation. At every stage there is an overdesign.
VFD, therefore, enables industries to control the speed
of essential devices like pumps, fans and compressors as
per requirement, thereby increasing these equipments’
efficiency and saving energy.
electric motor. For example, if you connect a 3-phase motor
starter with a fan, the motor consumes power through all
the three phases while delivering speed to run the fan at
a desired speed. But if you use a VFD, you have the ability
of operating the fan more efficiently at a variable speed,
thereby saving more energy. Since you have the option of
operating the fan at any desired speed below the maximum
level, there is an option of varying the airflow by controlling
the motor speed instead of making use of the air outlet
damper.
With the original outlet damper, you are likely to face a
few conventional problems like:
•
Non-linearity adjustment
•
Insensitive control
•
Serious energy waste
Speed adjustment can therefore be the best way to change
motor speed. Medium voltage VFD helps to ensure accurate
and timely air flow control. VFD also helps to overcome the
aforementioned disadvantages and saves energy.
Speed
Flow /
Volume
Power consumed
by Throttle/
Damper
Power
consumed
by VFD
100%
100%
100%
100%
90%
90%
96%
73%
80%
80%
92%
51%
70%
70%
88%
34%
60%
60%
84%
22%
50%
50%
80%
13%
40%
40%
76%
6%
30%
30%
72%
3%
The above illustrations explain the respective volume
consumption & power requirement details at particular
speed specified, for running a PUMP with VFD.
For instance, we can see at 100% speed, power
required for running the load is 100%. If the flow
requirement is 80%, the pump is required to run at a
speed of 80%. As illustrated above, the power required
is only 51%, if operated through VFD. If traditional
methods such as Throttle control are used, the motor
will still run at 100% leading to a power consumption of
92%. Hence, by installing a VFD, 41% of power can be
saved, thereby increasing profitability of an enterprise3.
Disclaimer:
This article is an original piece of work and contains only unique content developed after absorbing information from several websites. Sources
have been mentioned for all the statistics used in the article. The author does not take responsibility of the accuracy, correctness and validity of the
matter on the source websites.
3
Source: Siemens