When Compressed Air Consultants was starting, in 2003, we were approached by a company experiencing significant problems with their compressed air system. They had compressed air pressure problems causing production interruptions. They had moisture issues causing all kinds of havoc throughout the facility and appeared to be using far too many air compressors for what they wanted to accomplish.
The compressed air audit was performed and the project was implemented. The results were spectacular as the system went from running thirteen (13) air compressors down to seven (7) compressors. At the same time, air pressure was stabilized while air pressure was improved to more than acceptable levels. They did not purchase a single new air compressor, realized an annual energy savings well into six figures and the project delivered a very generous return on investment.
Fast forward to four years later when we called on the client. They were now running on twelve (12) air compressors and were having problems with the compressed air system again. You would think that somewhere along the line, some one would figure out there was a problem. But no one did. No flags were raised, no alarms sounded and no warning lights flashed. Money just poured down the drain.
We talked to several of the individuals who had implemented the project with us - as well as with others who joined the company after the project had been undertaken. They, like us, were disturbed when they saw the before and after snapshots. Everyone had good intentions throughout the audit, the implementation, and the ensuing years. We decided to do a post mortem and came to several interesting conclusions.
Four Principles for Sustaining Energy Savings
The root causes for the problems came down to four basic areas. First, there was a lack of system ownership. Second, there was a lack of understanding of how the system was supposed to operate in both supply and demand. Third, there was a complete lack of feedback, which would have informed the individuals in the plant that a course correction was needed. Finally, there needs to be a bias towards action when the feedback says you are off course. Due to these root causes, no actions were taken when the compressed air system changed for the worse.
1. System Ownership
The odds of sustaining energy savings increase substantially if someone is in charge of the compressed air system. When responsibility was dispersed throughout the organization, the system began to slip and degrade over time. The lack of an air champion on the supply or the demand meant that operators within the facility could do what they wanted without having some check and balance within the plant.
2. Operator Supply and Demand-Side Knowledge
Operator training is a vital component in sustaining energy savings. In this case, a significant effort was put forth immediately after the audit and after the project implementation so that a dozen individuals understood how the system was supposed to operate. As the positions and job titles changed within the organization, new individuals came in and had zero understanding of how the compressed air system was intended to operate.
For instance, the brain of the system was the control system. When they opened the door to the motor control center where the brain existed, we found that several of the wires from the air compressors to the control panel were cut. Apparently, there was a low-pressure problem at some point and the operators on duty did not understand the control system. Since they didn’t know how to put the compressors into local control (which was really quite easy to do), they elected to cut all the wiring. The pressure problem went away and no one complained about the air system.
On the demand side, bad practices returned as newer operators weren’t given an understanding of the cost of compressed air and the older operators reverted back to the norm. The organization ceased to care about the compressed air system from a cultural standpoint.
To sustain the energy savings of an implemented project, operator training (or reminders) on supply and demand needs to occur until the culture of the plant reaches a point where it is self-sustaining. In practice, this often takes years. If the compressed air champion is up to the task, he should lead these annual training sessions.
If the compressed air champion isn’t the one to train, then the plant can have their outside compressed air expert take the lead on the program as the cost of training is a fraction of the savings. In this particular plant, annual training would have been less than 0.5% of the lost savings. It should be understood that training on the cost of compressed air and on supply-side and demand-side issues is very necessary.
3. Establish a Feedback Loop to Enable Course Corrections
The third principle is that there needs to be a better feedback loop when the system gets off course. This course correction can come in several forms but the principle comes down to quickly getting information to those that matter, allowing them to act on that information.
Perhaps the most effective way is to track flow and energy and chart that against plant output in terms of product (widgets). Measuring flow will allow the plant to benchmark the amount of air they use, per widget, which in turn gives them feedback on the efficiency of the way the air is being used.
Measuring energy allows the plant to measure the efficiency of how the compressed air is made when it is compared to flow. The SCFM/kW metric tells the plant if the supply side is operating as it should be. Consider what would have happened in this system. As the operators started to use compressed air in more and more wasteful ways, the scfm per widget would increase. If it were graphed, there would have been a clear upward trend.
When the wires were cut from the control system allowing all the air compressors to operate in local control mode (and most were modulating type compressors), the SCFM/kw metric would have seen a huge bump and been obvious to anyone looking at it. These feedback loops would have told the operators in the control room that something was amiss. That would allow them to inform other individuals in the plant to go investigate.
And what if the operators in the control room had little interest in the compressed air system? Well there could be a little feedback loop for them. For larger systems, it is quite easy to log this data and generate reports which can be fed to management. Imagine the amount of time it would take for someone in authority to look at two numbers such as the average SCFM per widget this month and the average kw/scfm. It would take all of 30 seconds. If the change was large enough, then the need for the course correction would be clear. If the control room operators ignored the issue, perhaps the plant manager would give them a course correction.
4. Bias Towards Action When Off Course
The final principle is the requirement to act upon the changes in the compressed air system. The most obvious one is the need for ongoing leak repair. In accordance with the second law of thermodynamics, chaos always increases without some kind of input. That means leaks are going to develop and those that are leaking are going to leak more without some type of energy or effort put into it.
The same holds true with the demand. There will be an increase in waste in systems over time as operators who don’t understand, or don’t care, do their thing to keep production flowing.
In addition, due to the cost of compressed air, manufacturers of equipment that produce and consume compressed air are continuously developing new, more efficient technologies. Hence, your plant’s processes will become less and less optimized as technology changes.
The plant should schedule ongoing reviews, performed by outsiders, of the compressed air system. Sometimes it is just a new set of eyes that see something different that can make all the difference in the world. The compressed air reviews should cover leaks, demand-side and supply-side.
A significant portion of the projects that are implemented revert closer to the norm after a few years because the plant stops doing the things that got the great results in the first place. If the plant really wants to sustain those new-found energy savings, then something different needs to be done. These activities include designating an air champion, training operators on supply and demand, improving the feedback loop that something has gone awry and doing something about those issues once they are known.
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