Compressed air: Saving energy on the shop floor

PG&E
Compressed air: Saving energy on the shop floor

Compressed air is widely used throughout industry, but it's very wasteful. About 80 percent of compressed air energy use is lost as heat, according to the U.S. Department of Energy (DOE). Typically, only about half of the remaining compressed air does useful work. The rest is wasted through leakage, artificial demand and improper usage. In many cases, the best opportunities for compressed air energy savings are on the plant floor, not in the compressor room.


Leakage
Leaks often waste up to 30 percent of compressor output.


The best way to detect leaks is to use an ultrasonic acoustic detector, which recognizes the high frequency hissing sounds associated with air leaks. A simpler but time-consuming method is to apply soapy water to suspect areas.


To optimize savings, incorporate a leak detection program as part of your maintenance operations. Include scheduled inspection, tracking, repair and documentation.


Artificial demand
Artificial demand is the increase in compressed air consumption from operating at higher than necessary operating pressure.


Flow controllers reduce artificial demand by separating the compressors from the point-of-use equipment. Compressed air storage is also an efficiency strategy essential to meet demand variations.


Improper use
Compressed air is often used since it’s easy and reliable option, rather than a more efficient and less costly method.

  • Open blowing. Apply regulators or engineered nozzles to control air flow for open blowing applications. Use fans if high pressure isn't needed.
  • Part cleaning. Fans and low-pressure blowers are typically more efficient for cleaning parts than compressed air.
  • Personnel cooling. Using compressed air for this application is expensive and potentially hazardous. Use fans or tune air conditioning controls.
  • Air motors and pumps. Applications using air motors or air pumps are often performed more efficiently with an electric motor or mechanical pump.

A compressed air system evaluation can improve performance and reduce your operating costs. For more information, see the DOE guide Improving Compressed Air System Performance


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