Is compressed air expensive?
Compressed air is actually very expensive because only 10 to 30 percent of the electric energy input reaches the point of end-use. The remaining input energy converts to wasted heat or is lost through leakage. For example, to generate 8 M3/hr it takes 1 HP power.Compressed air leakage of 30 – 40 percent is not uncommon. Carry out periodic leak tests to estimate the quantity of leakage. Detection and repair can reduce leaks to less than 10 percent of compressor volume. Leak repair, when combined with adjustments to compressor controls, can reduce compressor run time, increase equipment life and reduce maintenance
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Keep the minimum possible range between load and unload pressure settings.
The compressor with the highest part-load efficiency is placed in trim service to handle variations in load.
Retrofit with variable speed drives in big compressors, say over 100 kW,
to eliminate the ‘unloaded' running condition altogether.
Reduce compressor delivery pressure, wherever possible, to save energy. Reducing and controlling system pressure downstream of the primary receiver can reduce energy consumption, leakage, demand for new capacity, as well as cause less stress on components and operating equipment.
Use blowers instead of compressed air to provide cooling, aspirating, blow guns, air lances, agitating, mixing, or to inflate packaging
Provide extra air receivers at points of high cyclic-air demand which permits operation without extra compressor capacity.
Pressure drop is the reduction in air pressure from the compressor to the actual point of use. A properly designed system should have a pressure drop of below 10 percent of the compressor's discharge pressure.
Eliminate inappropriate air users-Use brushes, blowers, or vacuum systems instead of compressed air to clean parts or remove debris
Cooler air is denser and provides more mass for each compression cycle with no additional power use. Lower inlet air temperature will result in less compressor work. Use outside air for cooling reciprocating and lubricant-free screw compressors when it is cooler than indoor air.
A smaller dedicated compressor can be installed at load point, located far off from the central compressor house, instead of supplying air through lengthy pipelines.
Automatic timer controlled drain traps wastes compressed air every time the valve opens. So frequency of drainage should be optimized.
Use blowers, electric actuators, or hydraulics instead of compressed air blasts to move parts
Properly designed heat recovery can recover 50 to 90 percent of the waste heat and use it to heat air or water. Common applications include supplemental space heating, industrial process heating, water heating, makeup air heating and boiler makeup water preheating.
Install equipment interlocked solenoid cut-off valves in the air system so that air supply to a machine can be switched off when not in use.
Carrying out pump up test, leakage test, specific power consumption determination regularly
Compressed air piping layout should be made preferably as a ring main to provide desired pressures for all users.
Present energy prices justify liberal designs of pipeline sizes to reduce pressure drops.
Benefits of energy conservation measures in compressed air system
Increased Profits
Improved Quality
Minimum Energy Input & Maximum Output
Reduced Energy bills
Increased Profits
Increased Competitiveness
Increased Productivity
Improved Quality
Reduced consumptions
Increased Competitiveness
Leakage @ ½”dia hole in Compressed Air line @ 7 Kg/cm2 can drain almost waste Rs.2500/- per day
Power consumption increases 1% for every 2 psi increase in compressor pressure
Every 100mm (water) pressure drop reduces the compressor capacity 1%
For every 12 degree C increase in water temperature, the power consumption will increase by 5%.