Electrical Equivalent Circuit Parameter Estimation of Commercial Induction Machines Using an Enhanced Grey Wolf Optimization Algorithm.

This study assessed technical potentials for energy efficiency improvement in 2050 in a global context. The reference scenario is based on the World Energy Outlook of the International Energy Agency 2007 edition and assumptions regarding gross domestic product developments after 2030. In the reference scenario, worldwide final energy demand almost doubles from 293 EJ in 2005 to 571 EJ in 2050 and primary energy supply increases from 439 EJ in 2005 to 867 EJ in 2050 (excluding non-energy use). It is estimated that, by exploiting the technical potential for energy efficiency improvement in energy demand sectors, this growth can be limited to 8% or 317 EJ final energy demand and 473 EJ primary energy supply in 2050. This corresponds to a potential for demand-side energy efficiency improvement of 44% in 2050, in comparison to reference energy use. In addition, a potential exists for improving energy efficiency in the transformation sector. In 2005, as much as 33% of primary energy supply is lost in the transformation and distribution of primary energy. It is estimated that this share can be reduced to 19% in 2050 by, e.g. improving energy efficiency of fossil-fired power generation (assuming no changes in the fuel mix for power generation). Including the potential for energy efficiency improvement in energy demand sectors, total primary energy supply would then decrease by 10% from 439 EJ in 2005 to 393 EJ in 2050. This contributes to a total potential for energy efficiency improvement of 55% in 2050 in comparison to reference primary energy supply.

This paper analyzes the effects of voltage harmonic distortion on the losses and efficiency of energy efficient induction motors (EEIM). Preliminary studies show that when fed with distorted voltages the new EEIM have a greater impact on efficiency than standard induction motors. Therefore, in this work a more precise steady state equivalent circuit is used to quantify accurately the impact of the distorted voltage waveform on losses and efficiency of induction motor. The model is validated using two induction motors both of 5.5kW, 50Hz, four poles; one is class IE3 Premium efficiency and the other is class lE1 standard efficiency. The analysis of the results may lead to infer that the EEIM are a good alternative to reduce energy consumption, but the margin is lower under fed with distorted voltages compared with ideal supply conditions.

Monogroove heat pipe design: Insulated liquid channel with bridging wick

This study aims to highlight a methodology for implementing an energy audit plan within industries. Today, international competitiveness involves optimizing companies’ production costs. This necessarily requires the implementation of rigorous energy saving policies. These savings are measures taken to limit energy consumption or to avoid energy losses. The energy audit is a methodical review and analysis of the use and consumption of energy; which attempts to identify energy flows and information on all the company’s energy consumption patterns. According to the information obtained in audit potential improvements in energy efficiency are carried out. In this paper, we present the results of an energy audit conducted within a company operating in the agri-food sector in the eastern region of Morocco. It has been shown that, in this case, the database resulting from the energy audit has contributed significantly to the development of a systematic approach to decision-making and consequently to the improvement of the energy efficiency.

Improving Energy Efficiency in South Asia

The chapter provides a perspective on sustainable supply chains and energy with clear implications: profit must meet planet. The chapter begins with a brief explanation of the key concepts and explanatory logic of energy efficiency as a mechanism of sustainable supply chains. This is developed further through a systems-level perspective as a means of scoping the potential for energy efficiency improvements. A set of four types of logistics situations that cut through the supply chain illustrate how supply chains set conditions for energy consumption and improving energy efficiency.

The cement industry is one of the most energy and emission-intensive sectors, accounting for approximately 7% of total-industrial energy use and 7% of global CO2 emissions. This study investigates the potential energy savings and CO2 abatement in the cement plants of Ethiopia. A Benchmarking and Energy Saving Tool for Cement is used to compare the energy use performance of the individual cement plants to best practices. The study reveals that all the surveyed plants are less efficient, with an average energy saving potential of 36% indicating a significant potential for energy efficiency improvement. Then, twenty-eight energy efficiency measures are identified and analyzed using a bottom-up energy conservation supply curve model. The results show that the cost-effective electrical energy and fuel-saving potentials of these measures are estimated to be 99 Gigawatt hours per year which is about 11.5% of the plants’ annual electrical energy consumption and, 2.7 Petajoules per year which is to be 12.5% of the plants’ annual fuel consumption, respectively. The cost-effective fuel measures have an annual average CO2 emission reduction potential of 254 kilo-tonnes per year which covers about 5% of the total CO2 emission. Sensitivity analysis is conducted using the key parameters that show some discrepancy in the base case results. This study could be used as a reference for policymakers to understand the potential for energy savings and CO2 abatement. It could also be used to design policies in improving energy efficiency in the cement sector.

Currently, the main direction in increasing the energy efficiency of induction motor drive (IMD) is the implementation of control systems, which have the function of regulating technological processes in addition to reducing electricity consumption. However, about 70% of all induction motors (IM) are low and medium power motors being a part of uncontrolled electric drive systems. Therefore, significant savings of fuel and energy resources can be achieved only through the improvement of the energy efficiency of the induction motor itself. One of the most important areas for further improvement of the energy characteristics of the IM is the structure of the stator winding, which in turn will positively affect the conditions of electromechanical conversion. The principles of construction of asymmetric twelve-zone stator windings and possible variants of combination of separate sections are reviewed in the paper. A method for calculating the magnetomotive force (MMF) for a given connection scheme of individual coils of a stator winding and the values of phase currents is suggested. The suggested method for calculating the MMF is implemented in MATLAB. A decrease in the level of higher harmonics of MMF created by an asymmetric twelve-zone winding in comparison with a conventional stator winding design is substantiated, making it possible to predict an improvement in the operational characteristics of an IM with an asymmetric twelve-zone stator winding.

Advanced technologies and energy efficiency in the iron and steel industry in China

This paper deals with load extrapolation methods and algorithms for the estimation of the energy efficiency of induction motors, starting from the electrical data generally available after parameter identification. The main aim of this paper is to help the readers move from the theoretical analysis to the experimental verification, which is suitable to be included in its own testing. For this reason, step‐by‐step algorithms are included in this paper. The first part deals with the determination of energy efficiency based on an original load extrapolation. Finally, experimental verification of the high‐power and high‐voltage induction motors is provided. Comparison between the values of the in–out method and load extrapolation method confirms the validity of the proposed algorithms. Compared to the direct in–out method, the error of the load extrapolation proposed in this paper is less than 1%.The load extrapolation method is mainly used for the high‐voltage and high‐power asynchronous motor. The high‐voltage and high‐power motor can be used to drive a low‐power motor to achieve coaxial twin trawling in the absence of a suitable power supply and matched load. The energy efficiency of a high‐power motor under different loads are measured and estimated using a mathematical fitting method. The estimated energy efficiency curves in the whole load range can be used to evaluate the high‐power and high‐voltage induction motor. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

The authors describe the modeling of squirrel cage induction motors and the derivation of steady-state and dynamic models that can be utilized in harmonic penetration studies. They present the results of laboratory testing of three-phase and single-phase induction motors to estimate these static and dynamic models. Such models are extremely useful in: identifying effective control strategies to enhance efficiency of variable voltage/variable frequency motor drives; assessing machine performance with excitation voltage and frequency variations; and identifying nonlinear load impedance models of induction motor loads in harmonic penetration programs such as Cyme and Harmflo software. These models were utilized in deriving efficient open-loop control strategies based on optimized volt/hertz (V/sub m//f/sub s/) ratio characteristics for minimum input power, minimum losses, and maximum efficiency. >

Energy efficiency improvement is the main target of many recent studies in various domains, especially for electrical drives which constitute the core of industrial applications. The simulation of induction motors is based on static and dynamic models that allow the study of their mechanical performances, as well as their power consumption and losses. However, the commonly used dynamic model doesn't take into consideration the core losses in the motor, which have a significant impact on its energy efficiency. The purpose of this paper is to present two methods for including core losses in the dynamic model of squirrel-cage induction motors (IM) in addition to the copper and mechanical losses that are already taken into consideration in the commonly used model. Core losses are introduced as an equivalent torque reduction in the mechanical equation, or as an equivalent resistor in the model's equations. The proposed model is essential for future studies aiming to improve the energy efficiency of the motor. Both methods are analyzed and simulated using Matlab/Simulink and the obtained results are experimentally validated. The performances of these proposed methods are compared in order to find the best suitable method for future applications and induction motor studies.

The share of equipment and power use in smaller data centers (DCs) is comparable with that of more massive counterparts. However, they grabbed less attention in the literature despite being less energy-efficient. This study highlights the challenges of setting up a computational fluid dynamics (CFD) model of a 180-m2 small-size high-performance computing (HPC) DC and the validation procedure leading to a reasonably accurate model for the investigation of the thermal environment and potential energy efficiency improvements. Leaky floors, uneven placement of computing equipment and perforated tiles preventing separation of hot and cold air, low-temperature operation, and excessive cooling capacity and fan power were identified sources of energy inefficiency in the DC. Computational fluid dynamics model predictions were gradually improved by using experimental measurements for various boundary conditions (BCs) and detailed geometrical representation of large leakage openings. Eventually, the model led to predictions with an error of less than 1 °C at the rack inlet and less than 5 °C at the rack outlet. The ultimate objective was to use the validated CFD model to test various energy efficiency measures in the form of operational or design changes in line with the best practices. Impact of leakage between the raised floor and the room, reduced airflow rate, cold-aisle and hot-aisle separation, workload consolidation, and higher temperature operation were among the phenomena tested by using the validated CFD model. The estimated power usage effectiveness (PUE) value reduced from 1.95 to 1.40 with the proposed energy efficiency measures.

Distortion of the supply voltage undoubtedly reduces the overall energy efficiency of induction motors. The goal of this paper is to evaluate additional harmonic losses in relation to the machine's initial efficiency rating. However, due to the relatively small amount of additional loss, the main drawback when evaluating the effect of supply voltage distortion on the machines' overall efficiency is the measurement accuracy of the current methods. In order to validate the effect of motor efficiency rating in relation to supply voltage distortion, the use of the parameter "harmonic active power" is suggested. This new strategy is subsequently validated by measurements and compared to current methods such as the NEMA MG1, or the procedure according to the IEC60034-2-3. Although this strategy is only valid under certain constraints, this new method enables a fast and highly accurate measurement of the additional loss. Consequently, this parameter is used to validate the effect of efficiency rating of induction motors in relation to the additional loss related supply voltage distortion.

A model of an induction motor with an asymmetric stator winding is developed; it may be represented as two phases connected in parallel or in series and displaced is space by some angle.