Energy efficiency? There's an app for that

As the iPhone grows in popularity, useful applications — or apps — are proliferating. Here we present a few of our favorite engineering apps involving energy efficiency. Many are available for download free of charge through the Apple iTunes store and supplier websites, while others charge a nominal fee.

Determine electric motor operating costs

Engineers can use the Baldor Energy $avings Tool (BE$T) from Baldor Electric Co. to determine annual operating costs and kilowatt hour (kWh) usage of an electric motor. Users select from menus of existing motor data such as rpm, voltage, horsepower output, and number of phases. The program compares the efficiency of an existing motor to a comparable Baldor Super-E NEMA Premium efficient motor, shows results, and suggests a replacement Baldor motor. Test analysis for one motor slashed annual electricity costs by $120, enough for a 46-month payback. What's more, calculations in this case showed the Baldor motor to be 84% efficient as compared to the existing 50%-efficient motor. Visit iTunes and search for Baldor.

VFD energy estimator analyzes savings

A useful $avings Predictor application from Yaskawa Electric America Inc., available on iTunes, estimates energy savings when using variable frequency drives instead of conventional volume control methods. Variable frequency drives — which control the speed of three-phase electric motors — are used in building automation, industrial, and agriculture applications, among others. Yaskawa says the payback period for installing drives is usually less than three years, and sometimes less than a year. The application is also offered as a free download at

Global motor efficiency standards in a snap

Energy-efficient motors can be particularly helpful for increasing the efficiency of automation systems. Political activities reflect the same urgency and are making the use of energy-efficient motors obligatory on the basis of global energy efficiency regulations. The SEW IE Guide app from SEW-Eurodrive helps engineers find answers regarding which energy efficiency class will become mandatory when and in what country. Use the app to obtain information on new global energy efficiency regulations for energy-efficient motors quickly and easily. Find the application at iTunes and find more detailed information at

V-belt efficiency tool

Emerson Industrial Automation offers a Browning V-Belts Efficiency Calculator application at It allows users to calculate projected energy savings when upgrading from a wrapped to a notched V-belt. By entering key usage data points including geographic location, motor horsepower, and days/hours per week, users have the ability to calculate energy savings onsite. The application is also available through iTunes: Search for Browning V-belt.

Turn your phone into a solar panel

The Solar Panel Advisor app from Microtrend Technologies Inc. makes your iPhone behave like a solar panel: Keep it facing the sun and click “compute” to display how much power could be generated with any size solar panel. Users can also try various cloud scenarios and see how the solar output changes. You can also hold the phone in various orientations and tilt angles to see how the orientation changes the output. Finally, the result is compared to the U.S. national average. The app can also e-mail results if you wish to have them sent to your Inbox. Search for Microtrend at the iTunes store.

LED calculator predicts light bulb savings

The Philips LED Calculator assists users in calculating the potential savings from installing Philips LEDs. It specifically compares the efficiency of Philips LEDs to halogen lights so users can see the tradeoffs. Download the app free at the iTunes store by searching for Philips.

Convert engineering units efficiently

Efficiency isn't just about energy — it's also about getting your job done in a timely manner. To that end, Convert2 is a useful and efficient iPhone application (from a group called AppoTize) that makes the conversions commonly required by engineers and scientists. This app is the only one available that also ensures integrity through consistency with official values in NIST Special Publication 811 — Guide for the Use of the International System of Units. A few examples of useful conversions include acceleration; angle; angular acceleration; area or second moment of inertia; and capacitance. Accuracy is guaranteed to seven significant digits, and notation can be scientific or general. Visit iTunes and search Convert2.

Power transmission reference tool

Martin Sprocket & Gear now offers Martin's Engineering Tools of the Trade — a mechanical engineering reference app available for download at the iTunes store. The application allows quick access to power transmission information and contains more than 200 formulas and conversions used by industrial professionals. Areas covered include bearings, belts, gears, kinetic energy, metalworking, shafts, sprockets, engineering data, commonly used formulas and conversions, drive selection charts, and more. All formulas can be saved for easy access, and results can be e-mailed. The application is also available through

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Your friend Terry has his opinions (Nov-Dec, 2010), but where is the research to back him up. I was unable to find any official documentation of the claims made in your article about the percentages of glass going into landfills and the brittleness of recycled glass, but I found many sources making contrary claims. What gives? Are you maybe too willing to give your friend expert status because he agrees with you?
Paul Mathews
Langley, Wash.

If you haven't found official documentation about the amount of glass winding up in landfills you haven't looked very hard. One source of data is the Container Recycling Institute which found that single-stream collection of recyclables, the most common type of curbside system where all the recyclables go in one container, results in 40% of the glass from recycling bins eventually ending up in landfills. In the same report, you will find that only recycled glass sorted by color is practical for reuse in bottles of any sort. The rest has to go into lower-end uses such as fiberglass if it is used at all.

That report, by the way, can be found here:

Thanks for the article showing that recycling isn't always the best answer. I enjoy articles showing alternatives to the Green Madness in which I am increasingly engulfed.
Jerry Fox
San Diego

The problem isn't that smart meters (Nov-Dec, 2010) provide customers with too much information but that they have been designed to provide too little, at least by Southern California Edison. After I installed solar electric panels, I had to replace my old analog meter with a digital time-of-use meter to realize the full cost savings. With the analog meter, you could glance at the wheel and estimate how much electricity you were consuming or generating, based on direction and speed of motion. The fancy new digital meters have several complex displays that cycle automatically, but none of them includes any useful units or labels and no instructions are available. The description of my monthly bill is completely opaque. Why do I get the feeling that Socal Edison doesn't really want me to consume less of its product?
Gerald E. Loeb, M.D.
Los Angeles

Send letters to the editor to EE&T Magazine, 1300 East Ninth St., Cleveland, OH 44114, or to [email protected]. Letters we publish may be edited for length or grammatical issues.

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