UK industry is wasting air

About ten per cent of UK industry's electricity bill comes from generating compressed air, but many companies don't even know how much air they need, let alone how much they are generating.

Compressed air is used in almost every industrial sector. “Some people call it the fourth utility,” a spokesperson for the UK Government’s Energy Efficiency Best Practice Programme (EEBPP) told edie.

Although compressed air is considered essential, it has been consistently left out of firms’ energy audits because it is seen as a support service or part of a factory’s contracted-out maintenance programme. “A lot of companies don’t know what their [compressed air] demand pattern is – some of them don’t even have a meter,” says the EEBPP spokesperson. “And you can’t improve efficiency if you’re not measuring something.”

EEBPP offers a free, one-day compressed air energy audit to qualifying companies (usually firms employing 25 or more employees, but terms are flexible). Once a firm knows how much compressed air it is generating EEBPP can generally recommend alterations, including:

  • an end to generating pressure when it isn’t needed
  • getting rid of redundant pipework and sharp turns
  • an end to overtreating air
  • making sure not to generate too much pressure
  • investigating heat recovery

Improved compressed air efficiency has two obvious benefits: lower greeenhouse gas emissions thereby reducing a company’s contribution to climate change; and lower electricity bills.

Recovering the heat produced during air generation is one area that offers great potential for the future. With 100 units of energy required to produce only 10 units of compressed air, a large amount of excess heat is created during generation and is not recovered.

Other ways of improving compressed air efficiency already available include:

  • buying air compressors with more efficient motors and drives – the Government wants to see energy efficient equipment priced at the same levels as less efficient models
  • using a variable speed drive in combination with fixed speed drives – the fixed speed drives generate a base load and the variable speed drive rises and falls to meet demand without wasting energy by switching machines off and on.

Most manufacturers of air compressors offer models with variable speed drives, including Motivair. Motivair is organising an energy management seminar near Dartford Tunnel on 27 January. Speakers will offer independent advice on reducing unnecessary compressed air consumption and Motivair will outline its real-time compressed air energy auditing service. For details contact Howard Dry-Parker or by telephone on 01932 765 577.

To speak with an EEBPP advisor about compressed air or any other industrial energy efficiency issue, ring the Energy and the Environment confidential hotline on 0800 585 794.

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