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Compressed air is not free

The US Department of Energy conducted a survey on compressed air systems. It found that compressed air systems account for 10% of all electricity used in manufacturing industries. 70% of all US manufacturing plants have a compressed air system and 50% of those plants have opportunities for large energy savings with low project costs.  Source: Assessment of the Market for Compressed Air Efficiency Services – Energy.gov

In manufacturing plants, awareness of compressed air efficiency is low. The primary objective is supplying a reliable and consistent source of air. Some manufacturers have service contract for equipment, but few address efficiency. 35% of manufacturers conduct leak prevention programs and 57% of manufacturers have taken no action to improve efficiency.  Source: Assessment of the Market for Compressed Air Efficiency Services – Energy.gov

Compressed air leaks often waste 20-30% of the compressor’s output. 

A study conducted by the US Department of Energy found that 80% of compressor upgrade recommendations do not require investment in new compressors, and instead are addressed through low cost system upgrades and an effective leak monitoring and repair program. The estimates in the table below are widely accepted by the US Department of Energy as well as compressed air industry specialists. The estimates assume sharp orifices, well-rounded orifices could be 60% higher than listed.

Estimated air flow losses due to leakage

Hole size Compressed air pressure
80 psi 90 psi 100 psi
1/16" 3.2 cfm 3.5 cfm 3.8 cfm
1/8" 12.7 cfm 14.1 cfm 15.4 cfm
1/4" 51 cfm 56 cfm 62 cfm

How are leaks found?

There are 3 basic strategies, and each have costs associated with them.

  1. No strategy – High energy cost, waste due to leaks accounts for 25 – 30 % of energy cost.
  2. Preventative– Some sort of leak detection program is in place. Inspections are scheduled on a monthly or quarterly basis. Traditional methods, such as soapy water at joints or ultrasonic detectors, are used. As leaks are found, they are repaired.
  3. Predictive – Continuous monitoring of compressed air usage quickly identifies areas of leakage. Maintenance is scheduled to minimize downtime. Very often, the capital investment of a new compressor is postponed.