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Compressed Air: Better Performance And Savings

Compressed air is – per unit of energy – the most expensive utility in your plant.

Most of the input energy is lost as heat with, at best, only about 15 percent remaining in the compressed air. Usually, about half of this compressed air does useful work.

The rest is wasted through leaks, artificial demand and inappropriate uses. Often, the best opportunities for savings and improving performance are in the plant, not the compressor room.

Leaks
It is not unusual for a facility to have 25 percent or more of its compressed air production lost to leaks. Think of this as throwing away money. Repairing leaks makes more compressed air available to do work. Leak detection and repair should be part of regular maintenance. Leaks are most easily found by listening as you walk through the facility when it’s quiet.

Artificial demand
Unreliable pressure at a point of use can be significant enough to slow production or cause defects. Instead of identifying the cause of unreliable pressure, a common response to this problem is to increase pressure at the compressor. This increases leaks and air use at unregulated end uses. The solution is to first stabilize pressure, then determine whether you need to increase it. Start at the point of use.

How much pressure drop is there near the point of use? Pressure loss through hoses, connectors, regulators, and filters can be surprisingly high and can often be reduced by eliminating unnecessary components and improving piping at the end use.

What pressure is required right at the point of use? Raising system pressure instead of reducing pressure loss at the end use will result in greater pressure variation and higher costs.

Do you have rapidly changing, intermittent end uses? Compressed air only moves so fast in a pipe, so pressure can drop significantly before the compressor responds. Changes at the air compressor, including increasing pressure, do little to increase air available to problem areas. These uses rely on air storage in the system.

Adding a compressed air storage tank as close as possible to the point of use will make compressed air available when and where it is needed. To make sure pressure is stable in the system and at nearby equipment, you may need to regulate the rate at which this tank is refilled.

Inappropriate uses
Many functions can be accomplished more inexpensively another way. Use engineered nozzles for open blowing; mechanical means for mixing, pumping, and conveying; and fans or blowers for drying, cooling, and vacuum generation.

All of these measures can improve your system performance. To take full advantage of cost savings, it is important to have compressor controls that can take advantage of reduced air use.

Call Greg Kelleher or Alan Fraser at 484-1125 to determine how much you’re spending on compressed air or on any other electrical system. Before you purchase any motor driven device, call us to help select and fund the most efficient choice.