Electric motor efficiency needs to extend to the system: Motor Summit 2010
Energy-efficiency conference presentations went well beyond electric motor topics to the system level. A meaningful approach to motor system efficiency must extend to associated equipment, such as pumps, fans, and drives.
Frank J. Bartos, P.E., is a Control Engineering contributing content specialist
The third edition of Motor Summit—an international forum dedicated to debating and promoting relevant motor system efficiency issues—presented a growing program on Oct. 26-28, 2010, in Zurich, Switzerland. This conference followed prior successful “summits” in 2007 and 2008 at the same locale. Motor Summit brings together experts from research, government, and the private sector to focus on the latest technological innovations, current state of market penetration, as well as strategies and actions needed to overcome barriers hindering widespread use of efficient motor systems.
Motor Summit supports various ongoing processes of the Electric Motor Systems Annex of the International Energy Agency’s Efficient Electrical End-Use Equipment program (IEA 4E EMSA), namely:
- European Union’s Energy-using Products Ecodesign Directive;
- Harmonized IEC (International Electrotechnical Commission) motor testing and energy classification standards; and
- NEMA Premium Motors minimum efficiency performance standard (MEPS), which became U.S. law in Dec. 19, 2010 (January 2011 in Canada).
Presentations at Motor Summit 2010 ranged widely from standards and regulations to market potential for new technologies, to testing and efficiency assessment of motor systems, and more. Summit segments consisted of “International strategy day” (Oct. 27), “Swiss implementation day” (Oct. 28), and two EMSA workshops: “IEA 4E: Testing Centers,” and “New Motor Technology” (on Oct. 26 and Oct. 28, respectively).
While electric motor efficiency was the Summit’s overall theme, a growing focus is expansion of efficiency concepts and regulations to the system level—that is, to include equipment connected to, or associated with, motors. Pumps, fans, and compressors comprise the most common examples of such equipment. Several Summit presentations addressed the system efficiency trend.
European efficiency regulation of pumps and fans received attention as part of the presentation “Current Status of Motor, Pump and Fan Regulations,” by Ismo Grönroos-Saikkala, of the European Commission’s Energy Efficiency of Products & Intelligent Energy Directorate. Regulation of fans in the 125 W-500 kW power range has been adopted by the European Commission (EC) in early 2011, with 1st tier efficiency requirements effective in Jan. 2013 and higher 2nd tier requirements in Jan. 2015, according to Grönroos-Saikkala. Regulation of clean water pumps is also planned for 2011. Further technical studies are planned for compressors and pumps used in pools and aquariums and for pumps applied in wastewater management.
Pump and fan (circulator) efficiency initiatives were discussed on three separate levels in “Product, Extended Product, and Systems Approach Developments within the Pump Industry across Europe,” by Steve Schofield, technical director of the British Pump Manufacturers Association Ltd. (BPMA).
Product approach comprises electric motors 1-150 kW together with water pumps (in commercial buildings, drinking water systems, food industry, and agriculture); circulators in buildings; and ventilation fans in non-residential buildings. Extended product approach consists of the combination of pump, motor, and variable-frequency drive (VFD)—either integral to the motor or as a separate unit. System approach adds piping and valves between consumers and a reservoir (including flow resistance) as well as the consumer/load to the above equipment.
The three approaches represent progressively more complex areas to implement, however they also provide higher potential energy savings. Schofield put energy savings potential of these approaches at 5, 59, and 59 terrawatt-hr (TWh), respectively.
Urs Steinemann, from the Swiss engineering consultancy Ingenieurbüro US, also covered this sector in “Energy Consumption of Fans, European Fan Efficiency Regulations.” Ecodesign requirements for fans driven by motors with input power between 125 W and 500 kW have been adopted by the EC. They will be introduced in three steps: first-tier efficiency values to apply by Jan. 2013, followed by higher second-tier values in Jan. 2015 (noted above), as specified in the regulation. The latter efficiency values are reportedly in line with so-called current best available technology (BAT). The third step is “an additional set of ‘target values’ given for a future benchmark that can become requirements in a later stage,” said Steinemann.
Fan types covered under the regulation include:
- Centrifugal, forward-curved and radial-bladed fan varieties;
- Centrifugal, backward-curved fan—with and without housing;
- Mixed flow; and
- Cross flow.
As expected in a meaningful standard, efficiency must be based on measurements. Both static and total efficiencies are specified, based on fan static and total pressure measurements, respectively, at specified inlet/outlet locations. Provision is made for the case where the fan includes a drive (VFD). Expected energy savings under this regulation are forecast to amount to 34 TWh of energy and 16 million metric tons of CO2 per year in 2020, according to Steinemann.
Permanent magnet motors
Most energy-efficiency standards for electric motors to date have involved ac induction motors due to the dominant role of that technology as the workhorse of industry. However, other motor technologies are coming under scrutiny because of concerns for overall energy savings potential, or to meet increasingly higher efficiency requirements. Permanent magnet (PM) motors comprise one such technology.
PM motors were the focus of the presentation, “IE4 Motors on the Horizon,” by John Malinowski and Michael Klein of Baldor Electric (now part of the ABB Group). “Dramatic improvements in magnetic and thermal properties plus present day cost advantages represent viable alternative today [for PM motors]”, said Klein, who was the topic presenter. “IE” refers to international energy efficiency class designation of motors by the IEC (see more in a related online article).
A case note compared a direct-driven, laminated frame internal PM motor with a two-speed induction motor powering a 45 hp (34 kW) fan load in a cooling tower application. The induction motor system included a gear reducer. Baldor’s results showed total PM motor system efficiency of 92% compared to 82.1% for the induction motor version—along with 6 hp less power input, lower noise level, and simpler installation for the PM motor system.
Insights about PM motors’ technological development in Switzerland were provided by Dr. Stefan Berchten, principal of MagnetDrives AG, in “Permanent Magnet Motors, Application and Efficiency Potential.” The presentation included historical perspective of PM motor technology as well as experiences with large PM machines in elevator, cable car, and wind power applications. Interestingly, all these apps involved direct-drive, “gearless” designs.
Berchten outlined design complexities associated with PM machines, which need to be minimized—for example, magnetic circuit design, load torque, pulsation, cogging torque, and noise. He explained that while investments are higher for PM motor technology there is an acceptable payback. Among Berchten’s conclusions were that PM production methods must be “reinvented,” which includes increasing the magnetic power of materials other than the highest rated rare-earth magnets.
Other Summit topics included VFD testing methods and various standards developments—including that for “small motors” (see related online article).
Organizers and sponsors of Motor Summit 2010 were The Swiss Agency for Efficient Energy Use (S.A.F.E.), in collaboration with the International Energy Agency’s 4E EMSA and the national SwissEnergy program. Control Engineering was a participant at Motor Summit 2008.
For full content of the Motor Summit 2010 program, visit http://www.motorsummit.ch
Frank J. Bartos, P.E., is a Control Engineering contributing content specialist. Reach him at braunbart(at)sbcglobal.net.
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