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Reducing energy for compressed air production
Q: What are some relatively simple steps for reducing energy costs associated with my plant's compressed air production?
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NiffAmbrosino, of Scales Industrial Technologies, says:
Although compressed air energy-saving measures will vary among manufacturing facilities, two common and simple steps are reducing the air compressor’soperating pressure and eliminating leaks.
Operate your compressed air system at the lowest pressure possible.
For every 2-psi decrease in operating pressure, positive-displacement-type aircompressors require approximately 1 percent less energy. For example, lowering a 100-horsepower rotary screw air compressor's pressure setpoint from 100 psig to 95 psig will reduce the energy required tocompress air by 2.5 percent. At $0.10 per kilowatt-hour, this calculates to approximately $1,900 per year in energy cost reduction. (Calculated energy cost reduction is based on the compressor running atfull capacity—operating 8,760 hours per year with a 93.6 percent motor efficiency). In addition, a decrease in system operating pressure will reduce compressed air consumption at any unregulated endusers, which includes any point in the plant that uses compressed air without the use of a pressure regulator.
One process to identify your compressed air system’s minimum pressure requirement is tolower the air compressor pressure set point by 1 or 2 psi at a time (after informing production). Confirm with production that all manufacturing equipment is operating satisfactorily, and then reducethe setpoint another 1 or 2 psi after a reasonable period of time. Determine energy savings by measuring kilowatt usage at the compressor(s) before and after each pressure adjustment. (If you lack theinstrumentation to read kilowatt usage, measure amperage and voltage on the starter’s line side to calculate kilowatts). Continue the process until production experiences a problem. At that point,...