Compressed Air Best Practices - February 2009 - (Page 32)

| 02/09 Focus Industry POWER PLANTS | SEVEN SUSTAINABILITY PROJECTS FOR INDUSTRIAL ENERGY SAVINGS Step #3: Reduce Peak Demand by Peak Shaving and/or Load Shifting Reducing the peak demand is often referred to as Peak Shaving or Load Shifting. The next step is to determine which pieces of equipment are causing this peak to occur. I have found that using electronic data loggers is a good way to find the guilty equipment and to have measured data to support the project. Identify major electric-using equipment that does not run 24 hours per day. Install a data logger on the devices and record the energy usage for a period of one week. Especially look for “batch” type processes. They may only be run a few times per day or week. These are often the guilty components in causing extra peak demand charges. Figure 3: The data logger is installed in the equipment power cabinet Once data loggers are installed, one can get a picture of when different pieces of equipment are operating and how it relates to overall demand charges. Figure 4 shows the results of four pieces of equipment and the results are aligned with the total electric profile for the plant. The shaded bar shows the peak period when electricity is most expensive. In this example, we found a few pieces of equipment that with only a few hour changes in the operating schedule could reduce the demand charge significantly. The idea is to operate equipment outside of the peak demand period. In the beginning, the operations manager did not want to consider changing equipment schedules. After being presented with a clear graph and the dollar value, he changed the equipment schedules. Step #4: Demand Shaving Another method is referred to as Demand Shaving. The idea is to find equipment that could be shut off or slowed down for a short period of time when a peak period is approaching. The type of equipment that is usually shut down or slowed down includes hot water heaters, cooling tower fans, electric ovens and air conditioning systems. The chart in Figure 5 shows the change in the electric profile that can be accomplished by using a Demand Shaving control system. The left side of the chart shows the load profile with the control system off, and the right side shows the control system on. Figure 4: Equipment Load Profiles Demand Shaving often requires that some automatic equipment be installed, which monitors the actual energy usage and is programmed with a set of rules to determine which equipment can be shut down or slowed down and for how long. An example of a company to review is Powerit Solutions, www.poweritsolutions.com. 32 www.airbestpractices.com http://www.poweritsolutions.com http://www.airbestpractices.com

Table of Contents Feed for the Digital Edition of Compressed Air Best Practices - February 2009

Compressed Air Best Practices - February 2009 Contents From the Editor Utility-Air News Compressed Air Audit of the Month Air Standards Instrument Air in Nuclear Power Plants Seven Sustainability Projects for Industrial Energy Savings The Pneumatic Advantage Personal Productivity Resources for Energy Engineers Wall Street Watch Advertiser Index Classifieds

Compressed Air Best Practices - February 2009

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