As with most systems around a busy industrial plant, items that are deemed the most important get measured and tracked. I’m frequently amazed by strict corporate purchasing policies that keep a tab on even the smallest items such as pencils and paper clips, implemented to prevent sticky fingers from costing the company a few pennies a day, yet the same companies let their compressed air systems run unmeasured, unwittingly wasting thousands of dollars in lost profits.
Most plant personnel have no idea how much their compressed air systems cost to operate, and they don't know whether the compressors are producing compressed air at top efficiency. Also, very few track their plant compressed air leakage and waste. Often, tracking a few key performance indicators (KPIs) will make all the difference in helping to encourage positive change, which will lead to efficiency improvements and savings.
The key is to implement an energy management system (EnMS) to track important system parameters, such as specific power (kW per 100 cfm) and energy consumption (kWh). Perhaps some measurement of leakage can be done during nonproduction hours, too, with repair efforts initiated when unacceptable levels are found. These measurements typically surprise compressed air system operators. For example, it's shocking to learn that your system might be consuming double the normal consumption in power per unit of compressed air output and wasting half of the air produced through excessive leaks. On some systems, the power consumed can be 10 times what would be expected, with leakage levels in the high-80-percent range. Are you in this category? If you are not measuring, who knows?
Most people imagine an energy management system as being expensive and complicated, but this doesn’t have to be true. Yes, best practices would dictate that a world-class industrial plant have energy, pressure, flow, and dew point tracked and analyzed by a permanent continuous monitoring system, and yes, the installation of such a system takes some funds. But an adequate monitoring system can consist simply of a log book, a calculator, and a stopwatch (like the one on your phone). Using the compressor hour meters, average compressor power and flow output can be roughly estimated, from which system efficiency and total power consumption can be tracked. And conducting timer tests of compressor duty during nonproduction hours can help you estimate and track leaks. Weekly recording of these parameters can help you see how your system is doing and identify whether any change occurs due to system failures. This tracking can also help you assess the value of your leakage reduction efforts.
If you are interested, more information on how to track compressor key performance indicators for an energy management system can be obtained by referring to Canadian Standards document C837-16 - Monitoring and energy performance measurements of compressed air systems.
Ron Marshall is a compressed air energy efficiency expert and a compressed air trainer at www.compressedairaudit.com
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