When good compressed air equipment goes bad

Over the years, many well-meaning companies have taken advantage of utility incentives to upgrade their compressed air system for premium efficiency. Sure, the new equipment costs more to buy, but the additional costs are usually paid for through lower electrical costs, or so you were promised. But sometimes things go wrong: Equipment is not set up correctly or malfunctions occur shortly after installation, for example. And if don't have proper monitoring equipment or monitoring strategies in place, you may not receive the savings you expected.

To prove your savings, you must ensure that you or someone competent measures your baseline pressure, energy, and flow to capture your plant profile before your project, so that you'll be able to compare against the conditions after the project. When the project is complete, the baseline must be recaptured and savings calculated in the same manner.

Sometimes you won't achieve the expected savings. There can be many reasons for this, and having some accurate baseline numbers can help you sort it all out and possibly troubleshoot and fix the issues. Some common problems:

  • New equipment doesn't operate correctly because of settings problems
  • New equipment has failed or energy savings features have not been correctly activated
  • Plant flows have changed
  • Plant pressure has increased,
  • Significant new leakage has occurred
  • There are seasonal changes in the plant flow, and the baseline was captured during different conditions
  • One or more production shifts has been added.

An example of one or more of these points comes courtesy of a wire manufacturer who during a plant tour proudly displayed his new variable-frequency drive air compressor. The compressor control had a screen that showed a histogram of the number of hours the compressor had spent at different percentage loading. The information collected showed the unit had been at 100% load for all of its operating hours - a very poor application of this technology. The customer had no idea, and presumably the salesperson who sold the compressor and set it up had no clue either. A simple change in the compressor pressure settings solved this issue.

Another example was with a food processor that purchased an expensive high-efficiency desiccant air dryer when its plant was built. Many years later, after experiencing constant problems with the dryer, a compressed air auditor placed monitors on the system and discovered efficiency problems. A careful inspection revealed that the dryer had been assembled incorrectly and had never worked properly in the first place. A simple change to the wiring solved this problem.

During my time with a power utility, it was my job to verify the correct installation of new energy-efficiency equipment, and doing pre and post-monitoring headed off many of the problems listed in the bullet points. I found that it's always best to expect the unexpected and check your installation both before and after some major work is done. Make sure you measure as you go along so you can ensure you're getting what you paid for. If something isn't up to snuff, you'll be able to prove that corrections are required.

You can get help with this by calling a reputable compressed air service provider - preferably someone who has attended a Compressed Air Challenge level 1 or 2 seminar. Learn more about compressor monitoring at Compressed Air Challenge's next Fundamentals of Compressed Air Systems seminar. Check out the calendar at www.compressedairchallenge.org.