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Blowing dollars on compressed air
Compressed air is a very useful, but costly utility for your business. Even at their best efficiency, compressors turn more than 80 percent of the input electricity into heat instead of compressed air. That means you can operate five electric-driven tools for the same amount of energy as one air-driven tool.

Air compressors operate most efficiently at full load. The two most common compressor types—rotary-screw and piston—are equally efficient at full load. However, most compressors tend to operate at part load most of the time because plant air loads fluctuate, and because compressors are typically oversized.

The options for part load control vary widely in efficiency and cost to operate. The table below describes some of the more common controls. The most effective way to reduce operating costs is through more efficient control, so matching the controls to your needs is critical.

The best time to address control is when you buy the air compressor. An efficient control, such as a variable frequency drive (VFD), will have a higher initial purchase cost. However, like most motor-driven systems, operating costs rapidly overtake the initial purchase cost of the equipment.

“The cost to operate an air compressor for just one year can easily exceed the capital cost of the compressor,” says Alan Fraser, EWEB Senior Engineer, Energy Management Services. “Making a purchase decision solely on initial cost is like judging the size of an iceberg by only the ice above the water.”

EWEB has incentives to encourage the purchase of VFD air compressors and other efficient electrical equipment. These incentives are available both for new purchases and for modifying existing equipment.

EWEB has helped many customers install rotary-screw compressors packaged with VFDs. The extra cost for a VFD compressor can have a quick payback considering the reduced electric bill, the Oregon State Tax Credit and the EWEB incentive.

Call 484-1125 and ask for an industrial representative to determine how much you’re spending on compressed air or any other electrical system. Before you purchase any motor-driven device, call us to help select and fund the most efficient choice.