Industrial Utility Efficiency    

Leaks

One of the best ways to reduce compressed air costs is to look for ways to reduce leakage flow, an unnecessary load that is a constant demand on the compressed air system. This flow is never-ending and occurs during production periods, and during quiet times at night or on weekends. Reducing the flow in a well-controlled compressed air system will result in the reduction of compressor energy consumption, usually by about $1,750 per every 10 cfm, and often reduces pressure loss, allowing your machines to run better. This article discusses some recent experiences in using an acoustical imaging leak detector.
Why are compressed air leak programs often ignored or even discouraged by management, in addition to some energy recovery minded third parties? This problem can be summed up as “Over Promise” and “Lack of Delivery”. In the 1990’s, the basic compressed air inefficiency energy transfer became a prime target for energy reduction programs promising great results with many low investments. Good payback programs, which they are indeed.
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?