Compressed Air Best Practices - May 2008 - (Page 44)

| 05/08 Compressed Air Industry AUTOMOTIVE ASSEMBLY | A PASSION FOR SAVING ENERGY process in “nailing the numbers” has really been refined. We have gone to this focus in the last couple of years. We used to just measure flow and pressure. The people who just measure amperage can provide misleading information. On a modulating control rotary screw compressor, amperage can read nearly the same — no matter what the load is. Measuring amperage also relies on accurate horsepower ratings (and flow outputs) from manufacturers. Amps can also mislead you if something is wrong with the compressor like a malfunctioning inlet valve. The Level 3 Audit examines the demand-side (as well as the supply-side) of the compressed air system. It involves static dynamic testing. What is the actual delivered pressure at the point of use? Sometimes there are choke points where pipes are restricting flows. The Audit examines storage, air leaks and inappropriate uses (like opening boxes with open blowing). Power Supply Industries Headquarters in Fenton, Missouri The Level 2 and Level 3 Audits provide the customer with a CEO/CFO level document which outlines the energy saving opportunity, the capital required and the actions required. We work nationwide for some large corporations and our emphasis is on getting the numbers right! What observations do you have on auditing practices out there? We think it is great that “energy management” has become popular. We are, however, concerned that some “auditors” may unwittingly provide customers with inaccurate information on their systems. The main problem out there is a lack of knowledge on how to measure and how to interpret the data. Flow should be measured with a hot wire anemometer flow meters. We’ve used many types of flow meters over the years and we like these. They can be faulty if you have moisture in the air. Droplets of water will increase the flow measurement artificially. You can cross-check that with amperage readings. The flow meters measure how quickly the flow of air strips heat from the probe. If liquid water hits it, the evaporative cooling distorts the reading. Pressure measurement is done with 0–150 psig, pressure transducers with 4–20 milliamp outputs. We recommend measuring dew point and ppm with devices using chilled mirror technology. A full-blown audit needs to involve more than just measuring flow or just measuring amperage. Otherwise, the audit is just a sales tool for those trying to sell a new air compressor. We have seen audits where only pressure was measured and a VSD compressor was purchased. The solution should have been to fix the intermittent demand with storage. “Our emphasis . is on getting the numbers right!” What are some other new trends you are seeing? We installed an unmanned compressor station two years ago. The customer asked us to take over their compressed air system. We were to supply their process air to ensure 99% uptime. We have 2 x 200 hp compressors with two desiccant dryers and two boosters to go to 650 psi. If there is a system glitch, the system dials a cell phone and we can dial back in and see what is going on with the system. We can remote monitor the system and see what the alarms were or view when the routine maintenance needs to be done. Slowly but surely, we see a growth trend here. Thank you, PSI, for your insights. For more information please contact Jack Bertelsmeyer, Power Supply Industries, tel: 636-343-5252, email: powersupply@psiind.com, www.psiind.com 44 www.airbestpractices.com http://www.psiind.com http://www.airbestpractices.com

Table of Contents Feed for the Digital Edition of Compressed Air Best Practices - May 2008

Compressed Air Best Practices - May 2008 Contents From the Editor Utility-Air News The Compressed Air Audit of the Month Pneumatics Real World Best Practices Delta Industries: Doing What is Right for Customers Delta Industries: Six Truths You Need to Know about Really Putting the Customer First Power Supply Industries Resources for Energy Engineers Wall Street Watch Advertiser Index Job Market

Compressed Air Best Practices - May 2008

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