Industrial Utility Efficiency
As part of its ongoing corporate initiative to find ways to reduce its energy bills, and the costly impact on the bottom line, a cleaning products plant, located southwest of Chicago, recently focused on improving their compressed air system operation. This company is a global leader in water, hygiene and infection prevention solutions and services. This article discussed their efforts to improve the operation of their compressed air system by implementing an innovative compressed air monitoring and control system.
This facility is part of a major corporation with dozens of manufacturing facilities where consumer good food products are processed and packaged for shipment to retail outlets. The factory was spending \$210,000 annually on energy to operate their compressed air system. This system assessment detailed four (4) project areas where yearly energy savings totaling \$100,855 could be found with an investment of \$100,000.
A large multi-service public utility provider was faced with an ongoing problem. The utility, which services 93,000 retail and wholesale customers, employed five oil-free compressors at one power generation facility, but, if they needed to take down Unit 2 at the facility, it almost always pulled Unit 1 down with it, overloading the system’s capacity and causing service interruptions.
This building products factory spent an estimated \$240,000 annually on energy to operate the compressed air system at their Midwestern facility. This figure will increase as electric rates rise from their current average of 7.8 cents per kWh. The set of projects recommended, by the system assessment, reduced these energy costs by an estimated \$104,336 or 43% of current use. Project costs totalled \$73,000, representing a simple payback period of 8 months.
Compressed air is an expensive medium; yet, many compressed air systems are wastefully managed with minimal system transparency. Capturing essential system performance data and monitoring critical air quality data is not only eye opening, it enables future investments in compressed air systems to be fact-based and traceable.
“I don’t understand. I attended the Compressed Air Challenge® Fundamentals and Advanced courses. I read every article and book I could find on improving the efficiency of compressed air systems. I developed great ideas about how to reduce my compressed air consumption. We fixed leaks, “right-sized” filters to reduce pressure drop, changed piping, moved some processes to shifts that used less compressed air, bought low consumption nozzles and educated our entire workforce. We did all of this work and I still have six out of six compressors running. Reducing my air consumption does not appear to have reduced my air production!”
The Trinity Mirror Group print works on Oldham is one of the UK’s largest newspaper printers. The nine presses in the facility produce around 1million papers every day, including the Independent, the Daily Mirror and a range of local, regional and sports titles. Printing on this scale does not come cheap in energy terms, however. The plant’s annual electricity bill is in the order of £1.5millon. With energy prices on the rise, and a strong desire to improve environmental performance and reduce its carbon footprint, the plant’s management has recently embarked on a project to cut energy use substantially.
It has been my experience that more than 50% of industrial air users don’t control their air compressor resources effectively. As a result, a tremendous amount of energy is wasted. When my firm does audits of plant energy consumption, it’s not unusual for us to encounter installations with large numbers of independently-controlled compressors that are all running at different pressure settings and different loads.
This furniture factory, located in the Midwest, was spending \$47,000 annually on energy to operate the air compressors in their five production buildings. The factory calculates energy costs using a blended electric rate of \$0.077 /kWh and runs on average only 2400 operating hours per year.
Compressed air is expensive to produce but when one realizes the actual cost of using compressed air to produce mechanical work it can be mind boggling. Various inefficiencies between the compressor and the ultimate end use can act like a tax, robbing a portion of this valuable energy source before it is used and making the ultimate cost of using compressed air for power far more than you know. Fortunately there are some things that can be done to reduce these costs and improve efficiency.
This chemical plant spent an estimated \$3,153,022 annually on energy (steam and electricity) to operate the compressed air system at their facility. The plant staff established their energy costs as 5.3 cents per kWh and \$9.00 /1,000 lbs of steam per hour. The set of projects implemented in this system assessment reduced energy costs by an estimated \$2,794,598 or 88% of current use. In addition, these projects reduce demand on the boiler systems and add reliability and back-up to the compressed air system.
