Compressed air systems can be inefficient, wasting up to 70-90% of the energy used to power compressors. Common issues include leaks, over pressurization, pressure drops, and misuse of compressed air for applications where other technologies would be more efficient. Implementing conservation measures like leak detection and repair, pressure optimization, proper sizing of distribution components, and replacing pneumatic tools with electric where possible can significantly reduce energy costs over the long term. Regular maintenance and monitoring compressor run times and pressures can also improve efficiency.

1. Energy Conservation in
Compressed Air System.

2. Compressed Air :
“Compressed air is air which is kept under a pressure
that is greater than atmospheric pressure.”

3.  Advantages of Compressed Air :
• Wide Availability of Air & its compressibility.
• Easy Transportability in Long pipes & its storage
in pressure
vessels.
• It is free from fire hazards.
• Ease of handling with control of pressure,
force, motion, etc.
• Reliability of operation and remote controlling.
• Easier maintenance & cost effectiveness.
• It does not cause any pollution

4.  Disadvantages of Compressed
Air :
Compressed air is not cheap as power medium and it is not as
safe as considered.
The main reasons are :-
• Loss of compressed air power due to inefficient control and
leakages.
• Loss of Energy due to poorly maintained transmission and
distribution.
• Damage may occur due to over pressure in storage vessel.
• Valves may seize at freezing temperatures due to presence
of moisture
in compressed air.

5. Industrial Uses of Compressed Air :
 To operate reciprocating tools e.g. in riveting ,hammers
,paving breakers ,diggers ,etc.
 To operate rotating tools e.g. air motors ,drills ,reamers
,grinders ,wrenches ,etc.
 In Vehicle propulsion (compressed air vehicle).
 Compressed Air Energy Storage.
 In Air Braking Systems:-Railway braking & Road vehicle systems
 Refrigeration using a vortex tube.
 Air-start systems in engines.
 In Operation & Control of valves & instruments.
 Use of air cushion to reduce friction to minimum level in
hovercrafts and air lift conveyors ,pneumatic elevators ,as
fluidizer for aerating solid product for reduction in apparent
density.
 Process gas compressing ,controls , and actuators in petroleum
Industry.

6.  Air Compressors :
 Air compressors account for significant amount of electricity used in Indian
industries.
 Air compressors are used in a variety of industries to supply process
requirements, to operate pneumatic tools and equipment, and to meet
instrumentation needs.
 Only 10-30% of energy reaches the point of end-use, and balance 70-90% of
energy of the power of the prime mover being converted to unusable heat
energy and to a lesser extent lost in form of friction, misuse and noise.

7. Types of Air Compressors :-
 Packaged rotary air compressors are most commonly
used because of their low noise levels and maintenance
costs. There are different types of packaged rotary air
compressor, including:
rotary screw, which is the most widely used type as it is
reliable, efficient and only needs basic routine maintenance &
rotary sliding vane.
 Reciprocating compressors are often used for small
industrial applications. Their specific energy
consumption is equal to or better than rotary
compressors. However, they can suffer from reduced
performance levels if not maintained properly.
 Centrifugal compressors are generally used for
applications that need a high volume of air. At high
flow rates, the centrifugal compressor is by far the
most energy efficient.

8. Components of Compressed Air System :-
Compressed air systems usually consist of the following components :-
 compressor
 air cooler
 air receiver tank
 filter
 dryer
 condensate trap
 distribution system
 The compressor produces compressed air at the required pressure.
 The air receiver tank acts as a reservoir to store and cool the
compressed air and helps make sure the system can cope with
variations in demand.
 The air cooler, filter and dryer all treat the air at different points in the
system. They remove impurities such as water, dirt and oil from the
air taken in by the compressor, as well as those added by the
compressor.
 Compressed air may be fed to various uses on a site via a distribution
system. These distribution systems can be relatively straightforward
or very complex.

10.  Compressor Performance :-
 Capacity of a Compressor :
“The capacity of a compressor is represented as Free Air
Delivery (FAD),i.e. air at atmospheric conditions at any specific
location.
It represents the actual rate of volume of air compressed and
delivered at atmospheric conditions represented as cubic meter
per minute (cmm).”
 Compressor Efficiency :-
Several different measures of compressor efficiency
are commonly used: volumetric efficiency, adiabatic
efficiency, isothermal efficiency and mechanical
efficiency.

13. Why & How to Conserve
Energy in Air Compressed
Systems ??

14.  Electric Energy, The Big Cost.
 Analyze the total cost of a compressed air system and
you’ll realize that power cost is significant.
 In just one year it could exceed the cost of the
compressor itself.
 Over a period of ten years, this could consume 70% of
your overall costs.
 That’s why it is important to investigate energy
efficiency when considering a new compressor.
 70% of Your Long-Term Compressor Cost is Electricity

15.  Electric Energy, The Big Cost.
76%
12%
12%
Compressed Air Cost in Perspective
Costs over 10 Years
Electricity
Maintenance
Equipment
 70% of Your Long-Term Compressor Cost is Electricity

16.  Cost Of Production Matters
It takes 7-8 HP of electricity to
produce 1 HP in an air tool.
Power consumed in
producing compressed air will
impact the competitiveness of
production units.

17.  Ways to Conserve energy & Improve
performance of compressed air systems :
1. Location of Compressors :
• The location of compressor & use of filters plays an important role
on the amount of energy consumed.
• The lower inlet temperature to compressor results into lower energy input.
• It is observed that “Every 40C rise in inlet air temperature results in a
higher energy consumption by 1 % to achieve equivalent output”.
• Since the compressor room has higher temperature than the surrounding air
temperature, it is essential that intake pipe to L.P. compressor must be
extended outside the compressor room in a shade.
Some of the important points to be considered to reduce energy
consumption are as follows :-

18. 2. Use of Air-filters:
• Air filters must be used to supply clean air at suction to
compressor to avoid wear of moving parts.
• Filters should have high dust separation capacity with minimum
pressure drop since higher pressure drop across the filter
increases the power consumption
3. Elevation :
• The altitude of a place has a direct impact on the volumetric
efficiency of the compressor.
• It is evident that compressors located at higher altitudes
consume more power to achieve a particular delivery pressure
than those at sea level, as the compression ratio is higher.

19. 4. Intercooling in between the stages :
• Intercoolers should be provided in between the stages to reduce the
power requirement to run the compressor.
• Ideally, the temperature of the inlet air at each stage of a multi-stage
machine should be the same as it was at the first stage. This is referred
to as “perfect cooling” or isothermal compression.
• The extent of power saved depends on the intercooling of air carried out
in the intercooler.
• It is observed that “An Increase in 6 degree Celcius in the inlet air
temperature to second stage results in 2% of specific energy consumption”
5.Using Variable Speed Drives:
• Variable speed drives should be used for capacity control of
compressors to reduce power consumption.

20. 6. By Controlling Pressure Settings :
• Compressor operates between pressure ranges called as loading (cut-in)
and unloading (cut-out) pressures.
• For the same capacity, a compressor consumes more power at higher
pressures. They should not be operated above their optimum operating
pressures as this not only wastes energy, but also leads to excessive wear,
leading to further energy wastage.
• The volumetric efficiency of a compressor is also less at higher delivery
pressures.
 Reducing Delivery Pressure :
“ A reduction in the delivery pressure by 1 bar in a
compressor would reduce the power consumption by 6 – 10 %.”

21. 7. Proper Arrangement of Pipe lengths & fittings :
8. Use Blowers in place of Compressed Air System :
• Blowers must be used for low pressure applications instead of
compressed air (e.g. in agitation, air for combustion of fuel,
conveying materials in pipes.)
• Misuse of compressed air should be avoided for cleaning floors ,
equipment cleaning, etc.
• Air Distribution system should be such that the length of pipe up to
point of use in minimum and uses minimum pipe fittings and joints
so as to reduce the pressure losses.
• Where possible the piping system should be arranged as a closed
loop or “ring main” to allow for more uniform air distribution to
consumption points and to equalize pressure in the piping.

22. 9. Reduce Leakages :
• It is necessary that the leakages in the compressed air supply &
distribution system are eliminated as far as possible.
• Leakage tests are conducted by ultrasonic leak detectors. It is
done by observing & locating sources of ultrasonic vibrations
created by turbulent flow of air passing through leaks in
pressurized system.
• Another method of leak detection is by conducting no load test.
The distribution system is supplied compressed by closing all the
terminal valves of consumption points. The load on the
compressor will eventually reflect that there is a leakage in the
system.

23. 10.Replace Pneumatic tools :
12.Avoiding loss of air pressure due to friction :
The loss of pressure in piping is caused by resistance in pipe
fittings and valves, which dissipates energy by producing
turbulence. The piping system will be designed for a maximum
allowable pressure drop of 5 percent from the compressor to the
most distant point of use.
Pneumatic tools such as drills and grinders should be replaced by
motor driven tools where ever possible since the energy consumption
is almost 5 % to 10 % of the compressed air system if these pneumatic
tools are used.

24. Case study:- NORGREN
 world leader in pneumatic components and
automation systems
 systematic self-examination and with the help
of safety and energy saving techniques and
products
 directly increase overall profits, as well as
making a valuable contribution to the wider
issues.

25.  Causes:-
leaks, pressure drops, over pressurization,
misuse of jets and poor compressor
management.
around 30% of the air produced is wasted.
 Causes:-
leaks, pressure drops, over pressurization,
misuse of jets and poor compressor
management.
around 30% of the air produced is wasted.

26. leakages
 Causes:-
 Aging pipe work, Flange connector gaskets
and pipe dope, loose Fittings, Flexible hoses
subjected to strain and abrasion, Couplings
with damaged seals, etc.
 Remedies:-
 planned maintenance routine that is
intolerant of leaks.
 Isolate systems when not in use
 Estimate the percentage of air lost to leaks.

27. Misuse of Jets
 Causes:-
 processes such as dusting, cooling,
separating and other tasks.
 jets are left permanently running.
 Remedies:-
 With a suitable valve and sensor, these
can be controlled automatically so they are
only on when required.

28. Over pressurisation
 Causes:-
Many systems run at full line pressure with the only
control being the compressor cut off switch.
 high friction demands higher set pressures.
 Remedies:-
 Use of pressure regulators at exit
 Check for correct lubrication

29. Pressure drop
 Causes:-
 resistance to flow by localized restriction
and general friction in pipes and components.
 Fitting a smaller filter
 Remedies:-
 Pipe routing should have gentle sweeping
bends where possible.
 large enough filters

30. Compressor Management
 Large compressor installations are likely
to be fitted with sophisticated power and
load management systems.
 These use figures of expected
consumption rate, storage volume and
pressure to tell the compressor how long
to run in an off load condition before
shutting down during times of low or no
demand.