Industrial Utility Efficiency    

Leaks

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.
Years ago, while managing the service department of my compressor distributorship, I received a call from a nearby customer who told me his 200hp compressor wouldn’t make any air. When I arrived at the plant I found the inlet air filter differential indicator showing “Red”, which indicates the filter element was dirty. When I pointed this out the maintenance manager said he had just changed the filter element; however, when I removed the element the compressor immediately started making air. He then admitted that the element was one that they had simply washed out approximately seven times before. Unwittingly, when he tried to save money by cleaning the filter element he was increasing his energy cost several times more than the cost of the element.
Why So Many Air Leaks - Even Today?! Energy conservation has been much talked about lately, in the media, the government, and at the water cooler. Lean manufacturing is also a popular topic these days, as are any ways to increase productivity, reduce costs, and increase profitability.  
“Instead of adding supply equipment, we fix air leaks and incorporate high-efficiency air nozzles, blower packages and point-of-use receivers.” These demand-side actions stabilize compressed air system pressure and this ultimately increases production output, reduces production down-time and spoilage costs, and decreases the power costs of the compressed air system.
This Midwestern prepared food company now spends $269,463 annually on energy to operate their compressed air system. This figure will increase as electric rates are raised from their current average of 6.2 cents per kWh. The set of projects recommended below will reduce these energy costs by $112,902 or 41%. In addition, these projects will enhance productivity and quality and reduce equipment maintenance costs. Estimated costs for completing the projects total $146,102, which represents a simple payback of 15.6 months.
Understanding the supply side of the system is important, but more important is first looking at compressed air demand. One demand that is consistently in need of attention in industrial facilities is the air flow caused by leaks.
The secret to success is to understand the nature of what type of leak produces a detectible ultrasound and what does not, along with the techniques that can be used for effective leak identification.
This refinery currently spends $735,757 annually on the electricity required to operate the compressed air system at its plant. The group of projects recommended in the system assessment will reduce these energy costs by an estimated $364,211 (49% of current use). Estimated costs for completing the recommended projects total $435,800. This figure represents a simple payback period of 14.4 months. The firm also reduced compressed air demand by 732 scfm allowing them to save $441,544 by down-sizing the back-up rental diesel air compressors.
This factory currently spends $735,757 annually on the electricity required to operate the compressed air system at its plant. The group of projects recommended in the system assessment will reduce these energy costs by an estimated $364,211 (49% of current use). Estimated costs for completing the recommended projects total $435,800. This figure represents a simple payback period of 14.4 months.
Compressed air leaks - every system has them.  Is a leak identification and control program economically rewarding and/or necessary? Upper management sometimes doesn’t recognize the true cost of not repairing air leaks.  Knowing the high cost of compressed air, why wouldn’t every facility with a compressed air piping system implement a continuous leak identification and repair program?
This commercial printing facility is located in the Northeastern part of the U.S.  Like most facilities, the plant has seen many changes over the years.