Energy Efficient Compressors

Making Compressed Air System Energy Efficient

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Leakage in some systems is as high as 50 per cent. This means, of the two identical compressors working, one is catering only to leakage and another delivering the required compressed air. An 1/8” orifice can drain out 23.8 CFM or `1.2 lakhs. (Refer to the table 1). Many compressed air systems also have unregulated flow, i.e. there are no pressure regulators at the point of use. The consumption of air reduces at low pressure and increases at higher pressure.

The effect this can have is seen when the load-unload press band is high. More air is drawn when the compressor is near unloading press and consumption reduces near load pressure. For example a machine consuming 23.8 CFM at 90 PSIG will start consuming 31.6 CFM at 125 PSI, resulting in more air drawn from the compressors. (Refer to table 1)

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TABLE 1: LEAKAGE RATES: (Specific power assumed – 18 KW/100 CFM)Potential savings PA – Rs. 1.20 Lacs PA(1 leak x 23.8 cfm x 0.18 KW/CFM x 7000 hrs/PA x `4/Kmh)
TABLE 1: LEAKAGE RATES: (Specific power assumed – 18 KW/100 CFM)Potential savings PA – Rs. 1.20 Lacs PA(1 leak x 23.8 cfm x 0.18 KW/CFM x 7000 hrs/PA x `4/Kmh)
(Source: CAC)

Compressed Air Energy Audits

Specific compressed air energy audits are becoming increasingly relevant as organizations realize the opportunities for cost savings. Results of such audits are as high as 30 per cent of the existing power cost. Such audits act like a health check for compressed air systems, exploring opportunities for major or minor improve-ments, identifying inefficiencies in the system or opportunities to avoid wastage.

It is important to understand that compressed air systems are dynamic and their need and requirement keeps fluctuating. Hence re-auditing or health checks are required periodically. Its time industries started making regular audits a part of their maintenance schedules.

Additional Information
Energy Audits
Making Compressed Air System Energy Efficient

Supply side audits – Efficiency of individual compressors and complete system, sizing of compressors and peripheral system w.r.t. demand, fluctuation in loading patterns, system capacitance - supply side.

Opportunities - energy saving products in supply side.

Demand side audits – Establish accurate peak and average demand, capacity required for major air consumers, optimum press for such consumers, pressure segregation, pressure profile across plant, System capacitance - demand side, leakage quantification, improper usage of air.

Opportunities - Energy saving products in demand side.

System audits – Complete study of supply and demand side.

Audits are primarily designed to cover these:

  • Air compressors
  • Controls
  • Air quality
  • Storage
  • Distribution
  • Demand (consumption