The facts

Frequently referred to as Industry’s ‘Fourth Utility’, there is no question that compressed air is extremely versatile and widely used. In fact it is absolutely necessary for many industrial processes such as powering instrumentation, control units, hand tools as well as to drive processes in thousands of applications.

However it does have its problems, particularly when inappropriately used.

Compressed Air – the downside:

Compressed air is expensive to produce. It can be as much as 30% of a total sites electricity usage. It can also be very wasteful, and as little as 8-10% of the electricity used is converted into usable energy. In addition, many systems waste around 30% of their compressed air through leaks, poor maintenance, poor control and often poor application planning.

Huge savings can be achieved by avoiding the inappropriate use of compressed air. Too often it is considered and regarded as a ‘free resource’ by companies totally unaware of the real cost to the business.

Many operations can be accomplished more economically using alternative energy sources, such as:

  • Use blowers to provide air for cooling, aspirating, agitating, mixing or to inflate packaging.
  • Use blower-driven air knife systems instead of compressed air to dry or clean conveyed parts or remove debris such as swarf or chippings.
  • Use low pressure, high velocity air for personnel de-dusting and blow-off applications
  • Use blower-driven solutions to dry bottles and cans prior to labelling and packaging processes

As a general rule, compressed air should only be used if safety enhancements, significant productivity gains, or labour reduction will result. If compressed air is used for an application, the amount of air used should be of minimum quantity and pressure and used for the shortest possible length of time.

Payback Analysis

Compressed Air

  • Number of nozzles
    16 x48mm wide nozzles (Wind Jet or Whisper Jet Type) used to cover a width of 800mm supplied at 5bar pressure.
  • System performance
    o Flow per nozzle: 690l/min
    o Number of nozzles: 16
    o Total flow in: 662.4 m³/hr
  • Compressor power
    Based on 9m³/kW (4CFM / HP): 73.60kW
  • Estimated annual running costs
    Cost of electricity (per kWh) = £0.12

Running cost per year (8 hours, 5 days, 48 weeks):
= £16,957.44 (0.12 x 8 x 5 x 48 x 73.60)

ACI Blower Driven System

  • Number of air knives
    1 x 800mm wide Air Knife giving continuous unbroken jet of air
  • System power
    7.5kW
  • Capital investment required
    Approximately £4000 for Air Knife System + £1500 for installation (£5500 total)
  • Estimated annual running costs
    Costs of electricity (per kWh) = £0.12

 

Running cost per year (8 hours, 5 days, 48 weeks):
= £1728.00 (0.12 x 8 x 5 x 48 x 7.5)

Annual Running Cost Saving = £15,229.44 (£16,957.44 – £1728.00)
Payback period for ACI System = 4.3 months ( £5500 / £15,299.44 x 12 months)

Summary

 

When compared to compressed air driven nozzle systems, blower-powered Air Knife Systems are:

  • More cost effective to operate – running costs can be reduced by up to 90%.
  • Quieter – due to lower pressure operation, the expansion ratio and turbulence of the air produced is reduced.
  • Cleaner – the air from the blower is both dry and oil free. No expensive additional filtration is required.
  • Safer – ACI centrifugal blowers operate on the principle of high velocity, low pressure air which presents no danger to operators.

More information can be found in the air knife systems section of our website.