January 11, 2021
The National Electrical Manufacturers Association (NEMA) partnered with the Northwest Energy Efficiency Alliance (NEEA) and the Cadeo Group to publish Power Drive Systems: Energy Savings and Non-Energy Benefits in Constant & Variable Load Applications, which examines the energy savings potential of using a power drive systems (PDS) with pumps. PDS is the combination of an electric motor, feedback sensors, and an adjustable speed drive that allows the equipment to manage the flow and reduce power usage. The group considered data from more than 400 in situ pumps located in the Pacific Northwest. It resulted in one of the first independent analyses to calculate the energy savings by adopting a PDS in commercial and industrial pumps compared to traditional fixed-speed motors.
The analysis results showed that energy savings were possible, with an estimated 43 percent reduction in energy demand for variable speed applications and more than 20 percent reduced energy use in constant speed applications.
“While using a PDS in a variable speed system is common, this analysis is the first research published showing the energy savings potential in constant load applications. The research showed that the estimated payback period could be under ten months in a constant load system. This was unexpected and exciting for the group,” said Cadeo Group Director Sara Widder. “The findings will hopefully address some of the questions related to using a PDS in constant load applications.”
“At a time when so many facilities are adapting to building usage from COVID-19, incorporating a PDS can optimize energy use until building occupancy returns to pre-COVID-19 levels,” added Nidec Motor Corp representative and Energy Management Committee Chair to the NEMA Motor and Generator Section Rob Boteler. “Since motor driven products use more than 40 percent of all energy in commercial and industrial processes, reducing energy consumption from motor systems is significant work.”
“NEMA has been promoting the benefits of looking at the entire system for energy savings over the last several years. The results of this paper support other work published by NEMA and shows the significant energy savings possible when shifting from component efficiency to system energy savings,” Boteler added.
Download Power Drive Systems: Energy Savings & Non-Energy Benefits in Constant & Variable Load Applications for free here. To learn more about the research process that went into the publication, watch this short video.
For more background information, NEMA wrote The Potential Impacts of Rebound Effects on Energy Efficiency Measures Forecasted for Power Drive Systems and High-Efficiency Electric Motors, highlighting the potential downsides from mandating higher efficiency motors (above Premium efficiency) into existing systems. The white paper on Reliable Short-term Operation and Safety Must Take Precedence over Efficiency highlights applications where increasing efficiency may compromise reliability or safety. NEMA has also published several guides and technical papers on how to use PDS with motor-driven systems, including Guide to IEC 61800-9-2—Determining Loss of Power Drive Systems (PDSs) in Extended Products and Adjustable Speed Electrical Power Drive Systems, Part 6: Guide for Determination of Types of Load Duty and Corresponding Current Ratings.