By

P K Srivastava

Forbes Marshall in

workshop on " Best Practices in Energy Efficiency

in Aluminium Sector”

Dated : 16th Dec 2016

ENERGY SAVING OPPORTUNITIES IN

ALUMINIUM INDUSTRY [MASTER AIR CONTROLLER]

The Energy cost

500 SCFM compressor (90 kw)

running for 24 hrs x 365 days with

70 % load & 30 % unload consumes

6,38,604 kWh /year

So @ Rs. 5 kWh it costs 32 lacs /year

which is purely the energy cost only.

This is around 4 times the capital cost of compressor itself.

Compressed Air Energy • Inefficient power source even if well maintained

Eight compressor horsepower One horsepower of compressed air yields . . .

Fluctuating Air pr. Problem In industries

The Root Cause Of Air Pressure Fluctuation

• Rate of demand and supply rate variations

• Lack of useful storage. (capacitance)

Conventional Solution when Demand exceeds

Supply

is to add more Compressors with which,

• Increase in Energy Consumption.

• Overpowering of entire system.

Artificial Demand

Reduce Artificial demand to Reduce the Total Plant

demand

This reduction directly affect the supply system i.e. overall reduction in

compressor working hours as a result of reduced demand side load &

hence in turn reduction in power consumption for the system.

The Living Example

Flow In

Flow Out

The flow output can be controlled as per the demand requirement

rather than just supplying to the demand users without any demand as

in where there is no dam or Control Device. This reduces the load on

the supply system & thus saves.

Controlled

flow

FM- Master Air Controller

Forbes Marshall Master Air Control (MAC) is an energy saving control system, which actively

helps control the balance across the demand and supply sides. It introduces a differential

pressure between the receiver and itself and thus creates a useful high-pressure storage.

This helps in isolating the compressors from the demand surges. Peaks in demand are

handled by MAC, rather than being directed towards the compressors. This allows compressors

to run for longer on no-load. As a result, mass of air is reduced and a high and compressor load

cycles are reduced. This decrease in compressor load cycles is directly proportional to the

decrease in energy consumed by the compressors.

Thus, due to the MAC compressors are protected from artificial demand and the have

to cater only to base demand, and resulting in savings on compressed air energy consumption.

Furthermore, a constant pressure is now delivered to all plants and pneumatic equipment,

increasing quality and productivity in production processes.

Existing Compressed air systems Generation side

Pressure

User side Pressure

With MAC

Without

MAC

Generation side

Pressure User side Pressure

The Installation Architecture

MAC creates storage due to controlled differential pressure across

upstream receiver & itself.

This storage isolates compressors from demand side peaks &

troughs.

Peaks are met with stored energy instead of additional horse power.

Fast response time by increased velocity due to pressure difference

(similar to potential difference as in electrical circuits) across itself

The Savings

Without

MAC

With MAC

Total Savings- = 1740 – 1560 = 180 kWh i.e.- 180 / 1740 = 0.1 = 10

% So @ 5 Rs./kWh = Rs. 3,28,500 /-

This is the simplest saving with a MAC & it can range from 10

% to 30 %

The Benefits

Without

MAC

With MAC

Benefits of Master Air Control

Saves energy consumed by air compressors by cutting artificial demand for air

Reduction in compressor loading & induces higher unloading period

Separates compressors from demand side peaks & lows, thus prevents compressor cycling to minimal

Consistent air pressure delivery to demand side

Enhanced useful air storage capacity

Accommodates to any make of compressor

Demand reduction tends to reduce leakages in plant

Features of Master Air Control

HMI for better GUI

History & trending feature

Fail safe operation

Accurate pressure control

Provision of pressure control via addition of air demand meter

Highly responsive to fine changes in demand

The Success Story

0

100

200

300

400

500

600

700

Average Energy Consumption (kWH)

Without MAC With MAC

Without MAC With MAC

Energy Consumed = 5510 kWH/day Energy Consumed =

4400 kWH/day

Energy Saved = 1110 kWH/day

Energy Cost Saving = Rs. 23 Lakhs per year

(10%)

The graph shows a actual saving figure of a Basic version of MAC

installed at one of our customers . The data shown is as provided by the

customer.

Questions??

PL. contact us….

Forbes Marshall

House No. 306, Road no. 7, Sonari West Lay Out , Jamshedpur – 831 011

Phone no. [+91 657 2319180, [+91] 92346 08069

Email : psrivastava@forbesmarshall.com