A common problem is plaguing compressed air system across the world, and it's costing millions of dollars in lost company profits. The issue is poor compressor control, which leads to wasteful compressor operation.
This problem usually starts the minute the compressed air system is turned on and continues throughout the life of the plant, often wasting millions of dollars in electrical energy. Most plants don’t know they have this problem because they fail to measure even the most basic energy performance indicators, and thus they operate blindly, leading them to pay unnecessary electrical charges for every month of operation.
It is common to see this problem even in new compressed air systems that utilize high-efficiency compressors with cutting-edge electronic controls and variable-frequency-drive operation. Often the equipment's control parameters are selected by personnel from the compressor service company, but sometimes these are made using faulty assumptions. Because the service companies don’t pay the compressed air electrical bill, the control parameters are often selected based on the service provider’s needs, not the customer's.
This leads to:
- Compressors running unloaded for numerous hours, consuming power but producing no air,
- Compressors fighting for control, with highly varying pressure regulation,
- System pressure running at levels much higher than is actually required, wasting energy though additional compressor power and higher-than-normal flow.
How can you tell you have a problem? Measure! Have your system checked for efficiency by a reputable compressed air auditor. Well-trained auditors will place measuring instruments on your compressed air system to determine your current baseline. Using the data collected, they can quickly spot control issues that might be costing you money. They can even calculate the system-specific power, which is like a system gas mileage rating, and perhaps advise you how to put measurement and control systems in place so you can efficiently control and monitor your system yourself.
Ask your auditor to have a look outside the compressor room, too. System leakage and inappropriate compressed air use often waste as much energy as that lost by poor control.
Some recent examples found:
- A diesel powerhouse wasting $81,000 per year in electrical costs because a compressor was running in a very inefficient operating mode;
- A pulse grain processor wasting 91% of its compressed air costs because of poor compressor and desiccant dryer control; and
- A pork processing company wasting 52% of its compressed air system electrical costs, worth $80,000 per year, because of improper compressor control. This customer had a very expensive two-stage VSD compressor that was set up incorrectly.
None of these sites had any idea it had a problem until its system was measured.
Recommendation: Stop wasting energy and get your compressed air system under control!
Ron Marshall is a compressed air energy efficiency expert at www.compressedairaudit.com
Join Ron at the Compressed Air Efficiency LinkedIn discussion group at https://www.linkedin.com/groups/12065406