There is an often used rule-of-thumb about air compressor discharge pressure reduction; for every 2 psi reduction the resulting compressor power is reduced by one percent. A good efficiency measure to save compressed air energy is to try to reduce plant pressure so that the compressed air system energy is reduced.
But another seldom discussed side effect of the pressure reduction can increase the power savings due to the pressure reduction even more. If the compressor pressure reduction also reduces the pressure fed to unregulated air demand then those demands consume less air. How much? The reduction in air flow works out to close to one percent for every one psi in lower pressure.
If your compressed air system is controlled properly it will reduce its power nearly proportionally with the pressure reduction and result in even more power savings.
For example a VSD compressor running at 100 psi may consume about 88 kW at full load. Reduction of pressure by 10 psi would reduce the power consumption by about 4.4 kW for a savings of $3,850 per year at 10 cents per kWh. Further to this if the plant load is unregulated the pressure reduction would reduce the flow by about 9%. Since the VSD would simply turn itself down to feed the lower flow it would now consume about 76 kW for an additional saving of 7.6 kW worth $6,650 per year. Overall the potential savings gained could be worth up to $10,500.
And guess what? Because the compressor is using less power it will run cooler and therefore last longer. And the cooler air it produces will benefit your air dryer and make it work better too! All kinds of benefits.
Learn more about the benefits of pressure reduction by attending a Compressed Air Challenge Fundamentals of Compressed Air Systems Seminar. To find the nearest location visit the CAC website. Our calendar of trainings is here.
