As part of an energy reduction effort, a Canadian technical college hired a compressed air auditor to do a leakage audit of their large campus, which houses over 30 mixed use buildings, including laboratories, research facilities, shops and classrooms. The audit found very few leaks, the reduction of which would achieve minimal savings; however, a few surprising items of interest were noticed during the study that showed very good potential for operating cost savings of 64% with an estimated \$45,000 per year in reduced energy and water costs. This article discusses some of the findings and how savings can be achieved on lightly loaded compressed air systems.
Their system was designed and built to achieve premium performance, yet in a recent compressed air assessment the numbers showed their system had surprisingly poor performance, and worse, their staff was unaware of the problems. This article discusses some of the challenges faced and some future solutions that could get their system back to higher performance levels.
Launched in 2006, the TTU-IAC program provides manufacturers in the state with free energy, productivity, and waste assessments – including best practices for compressed air systems, and blowers and vacuum, as well as cooling towers and chillers. The assessments to date have provided manufacturers in the program with \$27.48 million in recommended cost savings, equaling 3.82 trillion British thermal units of energy savings.
In terms of compressed air systems, it’s not unusual to see a plant with 10 to 15 air compressors, each of which is rated to provide 3,000 to 4,000 scfm of air. The air is used for everything from moving product, to powering pneumatic tools, pumps, and fans, to cleaning. There are easily 1,500 pneumatic control valves at a single plant.
Annual plant electric costs for compressed air production, as operating today, are \$147,469 per year. If the electric costs of \$750 associated with operating ancillary equipment such as dryers are included, the total electric costs for operating the air system are \$148,219 per year. These estimates are based upon a blended electric rate of \$0.087 /kWh. The air system operates 8,760 hours per year. The load profile or air demand of this system is relatively stable during all shifts. Overall system flow ranges from 800- 1,000 acfm during production. The system pressure runs from 95 to 80 psig in the headers during production.
So you’ve purchased an ultrasonic leak detector after a sales person gave you a demonstration on detecting compressed air leaks. You’ve read all those articles on how air leaks are wasteful, expensive and leakage programs provide good paybacks. Perhaps you’ve even had a go at a leakage survey. Either way, by now you’ve realised leakage programs are not as simple as they sound and without an ongoing plan of attack, you will probably never see the results you thought you could achieve. This article is written to illuminate common mistakes made in leak surveys and hopes to provide guidance on how to turn that around.
Petro Chemical Energy, Inc. (PCE) specializes in energy loss surveys for the refining and chemical industries. We’ve been providing Compressed Air Leak Surveys, Nitrogen Leak Surveys, Steam Leak Surveys and Steam Trap Surveys – for over twentyfive (25) years. We operate totally independent of all equipment manufacturers to ensure our clients receive a complete and unbiased report of the leaks in their facility. PCE has conducted compressed air leak surveys for hundreds of customers at thousands of sites. Undetected, compressed air and gas leaks rob efficiency in manufacturing and processing industries. As a result, businesses lose millions of dollars annually in energy costs and lost production time.
The Lafarge Cement Distribution terminal located in Winnipeg, Canada has significantly reduced the site electrical demand and energy charges by changing the way they transport their cement. Two new low-pressure rotary screw air compressors have replaced two large high-pressure air compressors that previously powered their dense phase transport system. The resulting power reduction has saved the company 46 percent in transport operating costs.
A small Australian company, Basil V.R. Greatrex (BVRG), is shaking up the compressed air industry in Australia. While other companies focus on the sale of more and bigger compressed air production equipment, BVRG is helping customers reduce their compressed air system size and lower system flow by attacking waste, inappropriate use, and at the same time improving air quality.
There is an often-quoted ratio of 7.5 hp input to one horsepower output used to illustrate the inefficiency of the energy transfer in compressed air systems. What this is saying is that you receive the benefit of only 13 percent of the energy you put into your air compressors as mechanical output at the shaft of a typical compressed air powered tool. While this ratio is generally true for compressed air system awareness discussion purposes, you should understand that in the real world compressed air efficiency is usually much lower.
Compressed air optimization measures adopted by PTMSB have reduced the consumption of compressed air by 31 percent resulting in savings of about 3,761,000 kWh per year in energy consumption. The monetary savings are MYR 1,090,627 per year (\$255,000 USD). The CO2 reduction is estimated at 2,735 ton per year.