Compressed Air Best Practices-August 2008

Focus Industry COMPRESSED AIR AUDITS | 08/08 | Data Logging Key to our efficiency effor are site scoping efforts studies, which are basica enhanced basically plant walk through audits, where brief site audits observations are done an nameplate data and collected. During these s studies data loggers are placed on the compr compressed air system to determine the air system profile. The duration of this data logging is nor normally 7 days, where the concept is to catch a full plant production cycle and get a general idea of how the system is operating. These scoping studies are not intended to be as accurate as full system audits and therefore only consist of basic pressure logging at a few strategic points to determine system stability and pressure differentials; and amp logging to determine the response of compressor amp input to changes in pressure. If the data is plotted on a graph using a time scale, a system profile will be created that will reveal key system characteristics. An experienced eye can use these graphs like a doctor uses an EKG and diagnose a number of system issues very quickly. An example of such a chart appears in Figure 1. After calibrating the amp data to measured power at various compressor loading levels, a power consumption estimate can be calculated. If the load profile captured during the data logging represents the average loading throughout the year, a projected annual system energy consumption total can be fairly accurately estimated. Further to this, the approximate flows produced by each compressor can be estimated by observing the average amp characteristics at various times. The average amp loading versus percent loading, for reciprocating and screw compressors, follows certain characteristic curves, with each curve depending on the applicable compressor control mode. Example curves for various control modes are shown in Figure 2. A commonly used method of determining the flow output of screw www.airbestpractices.com Figure 2 — Comparison of typical compressor operating modes. Note these curves have been simplified for illustration purposes and may differ from actual curves depending on individual compressor characteristics. 21 http://www.numatics.com http://www.numatics.com http://www.airbestpractices.com

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

Compressed Air Best Practices- August 2008 Contents From the Editor Utility-Air News The August Audit of the Month: A Vacuum System Audit Energized for Savings at Seattle City Light and Tacoma Power Know Your System CASE: Compressed Air Supply Efficiency Ecos Air: Managing Incentive Programs Kaeser Compressors: Loyalty, Energy and Growth Building Relationships at Cummins-Wagner McIntire is Moving Forward The 2008 A.I.C.D. Conference & Exhibition Tuthill Vacuum and Blower Systems Resources for Energy Engineers: Training Calendar & Product Picks Wall Street Watch Advertiser Index Job Market

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