Comparative Study of Induction Motors of IE2, IE3 and IE4 Efficiency Classes in Pump Applications Taking into Account CO2 Emission Intensity  
[PERSON]  
1 Nizhniy Tagil Technological Institute, Ural Federal University, 622000 Nizhniy Tagil, Russia; [EMAIL_ADDRESS]  
Department of Electrical Engineering, Ural Federal University, 620002 Yekaterinburg, Russia; [EMAIL_ADDRESS] (V.K. ); [EMAIL_ADDRESS] (V.D.) 1  
[PERSON]  
2  
[PERSON]  
2 Correspondence: [EMAIL_ADDRESS]; Tel. : +7-909-028-49-25  
[PERSON]  
2  
[PERSON]  
2 Correspondence: [EMAIL_ADDRESS]; Tel. : +7-909-028-49-25  
[PERSON]  
2 Correspondence: [EMAIL_ADDRESS]; Tel. : +7-909-028-49-25
and VSD 2-, 4-, 6-, 8-pole motors with a rated output of 0.12-1000 kW shall not be less efficient than the IE3 level from 1 July 2021. In addition, from 1 July 2023, 2-, 4- and 6-pole motors with a rated output of 75-200 kW shall not be less efficient than IE4 level. In many countries outside the European Union, IE3 motors are also mandatory [6]: Switzerland and Turkey adopt the regulations of the European Union; USA (0.75-200 kW, from 2017); Canada (0.75-150 kW, from 2017); Mexico (0.75-375 kW, from 2010); South Korea (0.75-200 kW, from 2017); Singapore (0.75-375 kW, from 2013), Japan (0.75-375 kW, from 2014), Saudi Arabia (0.75-375 kW, from 2018), Brazil (0.75-185 kW, from 2017). All aforementioned measures are aimed at the reduction of carbon dioxide (CO\({}_{2}\)) emissions, since CO\({}_{2}\) is one of the most dangerous greenhouse gases. Besides energy saving on the consumer side, usage of the sources with high energy conversion efficiency and renewable energy sources are also very important and results in a significant reduction in greenhouse gas emissions [7; 8; 9]. Pumps of various types consume about 22% of all electricity produced worldwide [3]. Therefore, studying the opportunities for increasing the energy efficiency of pump units is of current interest. Centrifugal pumps often do not require their drives to provide a wide speed-range adjustment, a high starting torque, or enhanced dynamic performances. For this reason, induction motors (IMs) fed directly from the mains are commonly used in this application. In this case, the fluid flow is adjusted by throttling. It can be also noted that these IMs are the most common solution in most applications because of the high cost of frequency converters. Thus, the variable-speed drives account only for 22% of the market in Germany [1] and about 20% in Switzerland [10]. Improving the energy efficiency of a pump unit is possible by optimizing the hydraulic network in which the pump operates, applying VSD, optimizing the load distribution (in the case of parallel-running pumps), and by the proper selection of the elements of the pump unit. In particular, electric motors of a higher energy efficiency level can be applied [11]. A large number of works provide comparative studies on the feasibility of pump systems employing motors various of various types (induction motors, synchronous motors with rare-earth magnets on the rotor, synchronous reluctance motors without magnets) [12; 13; 14; 15]. However, all these works are dedicated to the analysis of pump units adjusted by VSD. In this paper, the use of electric motors with a higher energy efficiency class is discussed as the most relevant way to increase the energy efficiency of pumps with throttle control. It can be noted, that according to document [3], IE-levels depend only on the motor efficiency in the rated loading point. However, it is typical for motors in pump applications to operate at underload most of the time. For example, low-power (\(\leq\)2.5 kW) circulator pumps in variable-flow systems have the following typical flow-time profile [16; 17; 18]: 25%-flow for 44% of the time; 50%-flow for 35% of the time; 75%-flow for 15% of the time, and only for 6% of the time the pump operates at the rated flow.