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Business Could Save $173m with Compressed Air Improvements

Air compressors present a variety of opportunities for saving energy, from leak reduction and air intake improvements, to maintenance, monitoring, specification and design, according to guidance from the Carbon Trust.

Of the total energy supplied to a compressor, as little as 8 to 10 percent is converted to usable energy at point of use, making it a very inefficient and expensive way of transferring energy. The Carbon Trust says businesses in the U.K. could save up to £110 million a year ($173 million) by taking simple actions, at little or no cost, to improve compressed air systems and processes.

The trust says that compressed air can be up to 30 percent of a facility’s energy use, with frequent users of compressed air including companies in aircraft and auto manufacturing, cement, ceramics, chemicals, electronics, engineering, food and drink, foundries, glass, insulation materials, minerals, paper and board, pharmaceuticals, power generation, rubber and plastics, steel, textiles, tobacco and water treatment.

Some of the opportunities for improvement are:

Usage and housekeeping

Switch off compressors when not needed, and ask if compressed air needs to be used at all. For example, compressed air is often used in pick-and-place operations, generating a vacuum to pick up an item and move it from one place to another. This can be accomplished with less energy using a vacuum pump.

Also ask how the compressed air is delivered. Venturi-type nozzles are usually more efficient than blow guns, as well as quieter and safer.

Leak reduction

For most sites, this is the single most important energy-efficiency action they can take. Well-maintained systems will lose about five to 10 percent of energy to leakage, compared to 50 percent or more in the worst-managed systems. Leaks can be detected from hissing or rattling noises (when the compressor is running without tools or equipment), by applying soapy water and seeing where it bubbles, or using ultrasonic leak detection equipment.

Improving intake air quality, generation and control

Intake air quality can be improved by ducting intake air from a suitable location, clear from exhaust ducts, free from obstructions and protected from the elements. Intake air should be as close to the outside air temperature as possible. Check the condition of the air intake filters – make sure they are not dirty or blocked.

Generation and control can be improved by matching control methods to demand requirements, using automatic shutdown control, controlling multiple compressors with an electronic sequential controller instead of a cascade pressure control, and integrating system controls into plant control or building management systems.

Air treatment

Companies shoud check air quality and pressure dew point. If only some processes need the air to be treated to a high level, consider treating all the air to a minimum specification, and then the needed amount to the higher level.

Air receivers and distribution systems

Companies should minimize pressure fluctuations, and identify opportunities to capture and re-use waste heat.

Maintenance

Planned maintenance and system checks should be carried out in accordance with manufacturer recommendations. Low-cost maintenance activities can save up to 10 percent of energy costs, according to tests carried out on over 300 typical compressors.

Monitoring

This should include monitoring of energy use, recording this use against production levels, and plotting the air volume produced against energy consumed.

Specification and design

Monitor demand before investing in new equipment, and consider the total cost of ownership. A variety of service contracts are available, including one, three, five or even 10 year-terms. Make sure the manufacturer provides information on energy consumption for full and no load, and for the total package power into the compressor, not just shaft power.

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4 thoughts on “Business Could Save $173m with Compressed Air Improvements

  1. Excellent article and absolutely correct. I would however take caution regarding the statement on air treatment. While the author is correct regarding cost of air treatment we have found many times if a plant utilizes multiple air systems for different pressures, drying all the air in conjunction with storage and demand expanders can allow end users to completely turn off one or more compressors.

  2. The author did well to put so much informaiton in such a short article. The opportunity is there although one would have to take issue with the assertion that leak reduction is the number one thing most plants can do. (There are some conditions where fixing a leak will have no energy impact as the control strategy for the compressor doesn’t accomodate the change in demand.) If the proper controls are not in place, then they are typically have the greatest impact on cost reduction. If the proper controls are not in place, leak reduction can have minimal to no effect. Leak reduction, while important is usually somewhere between third and sixth in priority from an energy perspective. From a cost perspective, it generally does have a higher ROI if the proper control system is in place.

    The key to air system improvements is to have enough understanding of the system’s dynamics in both supply and demand from an economic perspective that intelligent business decisions can be made.

  3. Thank you all for this positive feedback, I have found that,similar to process steam, these 2 “expensive services” are always neglected and even not taken as part of a process. Even if continuous breakdowns occur on equipment, you point out it is water in the system or even dirt – no, no, no , it is a faulty cylinder or some other “clever ” excuse. I know the CA and Steam reticulation system from design stage and find it very shocking that people are so careless. As they say … little knowledge could be very dangerous.
    PAUL, you mention the control strategy must be in place … where could I obtain such info.. whereby leakages are about 3 to 6 down the list. Thank you ( as mentioned I am mainly concerned distribution with key points as in the take-off points, drainage,drying, etc AND would enjoy to find as you say “understanding of the systems dynamics”

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