Drives: Calculate the savings to visualize the impact

The savings analyses provided by energy savings calculators can offer a detailed breakdown explaining where, how, and what exactly you are spending and saving over time.
By Control Engineering Staff January 20, 2009

Just as important as finding ways to try and conserve energy and save money, is discovering exactly how much you could save with a particular technology and then determining if it is worth making the switch. Analysis documents such as an energy savings calculator, predictor or indicator—available from many vendors—can help out with this process.
For motors and drives, Yaskawa.com offers a free tool—the Energy Savings Predictor. “To get started you need to document all of the three-phase motors in the facility including equipment tag and nameplate data,” says Ron Koehler, Director of Next Generation Products for Yaskawa. “First concentrate on all the fans, pumps, and cooling towers, before documenting all of the three-phase motors not operated by variable frequency drives (VFDs). Using a payback analysis tool, you can determine the payback after the installation of a VFD. If the payback can be shown to be achieved in less than three years, send the recommendation onto the facility manager for approval. Many times the payback can be a year or less, and utility companies often offer rebates for installing VFDs.”
Bottom line: the savings analyses provided by such tools offer a detailed breakdown explaining where, how, and what exactly you are spending and saving over time.
To provide an idea of the savings calculable via these analysis tools, consider a 10 HP pump operating 3,120 hours per year (5 days a week, 12 hours a day, 52 weeks a year). The annual power savings achievable with this pump by adding a VFD would be $879 based on a cost of $.07cents per kWh. For a more detailed analysis example using data from Yaskawa’s Energy Savings Predictor, see the Energy Savings Report graphic below.

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