Vol.119, No.3, 2022-Table of Contents

On the Cover

Phase change materials (PCM) have great latent heat but suffer from low thermal conductivity. Then, in recent years, nano particles have been added to PCM to improve their thermophysical properties such as thermal conductivity. Effect of this nano particles on thermophysical properties of PCM has been a question and many experimental and numerical studies have been done to investigate them. Artificial intelligence-based approach can be a good candidate to predict thermophysical properties of nano enhance PCM (NEPCM). Then, in this study an artificial neural network (ANN) has been developed to predict the latent heat of the NEPCM.
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  • Latent Heat Prediction of Nano Enhanced Phase Change Material by ANN Method
  • Abstract Thermal characteristics of phase change material (PCM) are important in design and utilization of thermal energy storage or other applications. PCMs have great latent heat but suffer from low thermal conductivity. Then, in recent years, nano particles have been added to PCM to improve their thermophysical properties such as thermal conductivity. Effect of this nano particles on thermophysical properties of PCM has been a question and many experimental and numerical studies have been done to investigate them. Artificial intelligence-based approach can be a good candidate to predict thermophysical properties of nano enhance PCM (NEPCM). Then, in this study an artificial… More
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  • Effect of Varying Temperature and Oxygen on Particulate Matter Formation in Oxy-Biomass Combustion
  • Abstract Offsetting particulate matter emissions has become a critical global aim as there are concerted efforts to deal with environmental and energy poverty challenges. This study consists of investigations of computing emissions of particulate matter from biomass fuels in various atmospheres and temperatures. The laboratory setup included a fixed bed electric reactor and a particulate matter (PM) measuring machine interfaced with the flue gas from the fixed bed reactor combustion chamber. The experiments were conducted at seven different temperatures (600°C–1200°C) and six incremental oxygen concentrations (21%–100%). Five biomass types were studied; A-cornstalk, B-wood, C-wheat straw, D-Rice husk, E-Peanut shell, each pulverized… More
  • Graphical Abstract

    Effect of Varying Temperature and Oxygen on Particulate Matter Formation in Oxy-Biomass Combustion
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  • Power Quality Assessment Based on Rough AHP and Extension Analysis
  • Abstract Due to the increasing power consumption of whole society and widely using of new non-linear and asymmetric electrical equipment, power quality assessment problem in the new period has attracted more and more attention. The mathematical essence of comprehensive assessment of power quality is a multi-attribute optimal decision-making problem. In order to solve the key problem of determining the indicator weight in the process of power quality assessment, a rough analytic hierarchy process (AHP) is proposed to aggregate the judgment opinions of multiple experts and eliminate the subjective effects of single expert judgment. Based on the advantage of extension analysis for… More
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  • A New Proximity Indicator for Assessment of Voltage Stability and Critical Loadability Point
  • Abstract This paper presents a newly developed proximity indicator for voltage stability assessment which can be used to predict critical real system load and voltages at various load buses at critical loading point. The proximity indicator varies almost parabolic with total real load demand and reaches orthogonally to real load axis. This relation has been utilized to predict critical loading point. It has been shown that two operating points are needed for estimating critical point and proper selection of operating points and variation of proximity indicator near collapse point highly affect the accuracy of estimation. Simulation is based on load flow… More
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  • Bi-Level Energy Management Model of Grid-Connected Microgrid Community
  • Abstract As the proportion of renewable energy power generation continues to increase, the number of grid-connected microgrids is gradually increasing, and geographically adjacent microgrids can be interconnected to form a Micro-Grid Community (MGC). In order to reduce the operation and maintenance costs of a single micro grid and reduce the adverse effects caused by unnecessary energy interaction between the micro grid and the main grid while improving the overall economic benefits of the micro grid community, this paper proposes a bi-level energy management model with the optimization goal of maximizing the social welfare of the micro grid community and minimizing the… More
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  • A New Approach for Structural Optimization with Application to Wind Turbine Tower
  • Abstract This work takes the bionic bamboo tower (BBT) of 2 MW wind turbine as the target, and the non-dominated sorting genetic algorithm (NSGA-II) is utilized to optimize its structural parameters. Specifically, the objective functions are deformation and mass. Based on the correlation analysis, the target optimization parameters were determined. Furthermore, the Kriging model of the BBT was established through the Latin Hypercube Sampling Design (LHSD). Finally, the BBT structure is optimized with multiple objectives under the constraints of strength, natural frequency, and size. The comparison shows that the optimized BBT has an advantage in the Design Load Case (DLC). This… More
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  • Transient Simulation and Optimization of Regional Integrated Energy System
  • Abstract A modeling method of regional integrated energy system based on bus method and transient simulation is proposed, and the system optimization is based on the dynamic balance of supply and demand in the whole year energy supply cycle. A CCHP system of gas turbine coupled with ground source heat pump and electric refrigeration unit is constructed. The energy relationship of the system is described by bus structure, and the transient calculation model is built on TRNSYS platform. The weighted sum of annual total cost saving rate, primary energy saving rate and environmental pollutant shadow cost saving rate is taken as… More
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  • Comprehensive Energy-Saving Optimization Model of Asynchronous Motor for Voltage Regulation Based on Static Synchronous Compensator
  • Abstract There are several problems existing in the direct starting of asynchronous motor such as large starting current, reactive power absorption from network side and weak interference-resistance, etc. Aiming at this, a comprehensive energy-saving optimization model of asynchronous motor for voltage regulation based on static synchronous compensator (STATCOM) is put forward. By analyzing the working principle and operation performance of static synchronous compensator regulating voltage, a new energy-efficient optimization method for asynchronous motor is proposed based on the voltage regulator model to achieve soft start, continuous dynamic reactive power compensation and the terminal voltage stability control. The multi-objective optimal operation of… More
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  • Distribution Network Equipment Location and Capacity Planning Method Considering Energy Internet Attribute from the Perspective of Life Cycle Cost
  • Abstract For facing the challenges brought by large-scale renewable energy having access to the system and considering the key technologies of energy Internet, it is very necessary to put forward the location method of distribution network equipment and capacity from the perspective of life cycle cost. Compared with the traditional energy network, the equipment capacity problem of energy interconnected distribution network which involves in electricity network, thermal energy network and natural gas network is comprehensively considered in this paper. On this basis, firstly, the operation architecture of energy interconnected distribution network is designed. Secondly, taking the grid connection location and configuration… More
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  • Establishment of a Coupling Model for the Prediction of Heat Dissipation of the Internal Combustion Engine Based on Finite Element
  • Abstract The aerodynamics and heat transfer performance in the rear-mounted automobile cabin have an important influence on the engine's safety and the operational stability of the automobile. The article uses STAR-CCM and GT-COOL software to establish the 3D wind tunnel model and engine cooling system model of the internal combustion engine. At the same time, we established a 3D artificial coupling model through parameter transfer. The research results show that the heat transfer coefficient decreases with the increase of the comprehensive drag coefficient of the nacelle. This shows that the cabin flow field has an important influence on the heat transfer… More
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  • Optimization Scheme of Integrated Community Energy Utilization System Based on Improved Sine-Cosine Algorithm
  • Abstract China consumes significant amount of natural gas in winter. The integrated community energy utilization system (ICEUS) cannot stabilize the output of electricity and heat if there is a shortage of natural gas. The operation cost of the system still needs improvement. An energy supply structure using garbage power as the core of ICEUS was established in the study. The optimal dispatching model of ICEUS was established using the regulating characteristic of the community load. The sine-cosine algorithm (SCA) based on nonlinear factors and segmented weight was presented to solve the optimal dispatching model of ICEUS. From the simulation results, compared… More
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  • Optimal Decision-Making of Trans-Provincial Electricity Market Subjects with Risks under Renewable Portfolio Standards
  • Abstract

    The randomness and uncertainty of renewable energy generation are expected to significantly change the optimal decision-making of trans-provincial electricity market subjects. Therefore, it is beneficial to optimize the interests of each of these subjects, considering the unpredictable risks of renewable energy under the renewable portfolio standards (RPS) and researching their effects on the optimal decision-making of trans-provincial electricity market multi-subjects. First, we develop a trans-provincial trading market mechanism for renewable energy and clarify the electricity supply and demand relation and the green certificates supply and demand relation of trans-provincial electricity market multi-subjects. Then, under the RPS, we construct a multi-subject… More

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  • Stepwise Pyrolysis by LBCR Downstream to Enhance of Gasoline Fraction of Liquid Fuel from MMSW
  • Abstract Pyrolysis is one of the thermal cracking methods to convert hydrocarbon to liquid fuel. The quantity and quality of the process are dependent on several condition including temperature, reaction time, catalyst, and the type of reactor. Meanwhile, a gasoline fraction was maximum product to be considered in the pyrolisis process. Therefore, this study aims to increase the gasoline fraction in liquid fuel using stepwise pyrolysis with a long bed catalytic reactor downstream (LBCR). The LBCR downstream was equipped with the top and bottom outlet and the fed source was mixed municipal solid waste (MMSW). The activated natural dolomite at 500°C… More
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  • An Insight into the Second-Harmonic Current Reduction Control Strategies in Two-Stage Converters
  • Abstract Due to the components at twice the fundamental frequency of output voltage in the instantaneous output power of a two-stage single-phase inverter (TSI), the second harmonic current (SHC) is generated in the front-end dc-dc converter (FDC). To reduce the SHC, optimizing the control strategy of the FDC is an effective and costless approach. From the view of visual impedance, this paper conducts an intensive study on the SHC reduction strategies. Origin of the SHC is illustrated first. Then, the equivalent circuit models of the FDC under different control strategies are proposed to analyse the SHC propagation characteristic. The derived model… More
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  • A STA Current-Constrained Control for PMSM Speed Regulation System with Function Disturbance Observer
  • Abstract The non-cascade permanent magnet synchronous motor control system has the advantages of simple structure and less adjustable parameters, but the non-cascade structure needs to solve the problem of over-current protection. In this paper, a current constrained control method is used to limit the starting current to a safe range. At the same time, to ensure the robustness and rapidity of the system, a super twist current constraint controller (CCSTA) is generated by combining super twist algorithm (STA) with current constraint control; Considering the diversity of internal and external disturbances, a functional disturbance observer (FDOB) is proposed to compensate the matched… More
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  • A New Diagnostic Method Applied to Gearbox Missing Gear Faults ——LOD-ICA
  • Abstract With the increasingly stringent requirements for carbon emissions, countries have increased the scale of clean energy use in recent years. As an important new clean energy source, the ratio of wind power in energy utilization has been increasing. The horizontal axis wind turbine is the main form of wind power generation, which is subject to random wind loads during operation and is prone to various failures after a long period of operation, resulting in reduced power generation efficiency or even shutdown. In order to ensure stable external power transmission, it is necessary to perform fault diagnosis for wind turbines. However,… More
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  • Characteristics of Diesel/N-Butanol Blend on a Common Rail Diesel Engine with Exhaust Gas Recirculation
  • Abstract 20% n-butanol is blended in diesel by volume (noted as D80B20) and experiment has been carried out to study the effect on the combustion and emission characteristics based on a common rail diesel engine with exhaust gas recirculation (EGR) system. The results reveal that D80B20 has longer ignition delay, shorter combustion duration and higher maximum in-cylinder temperature than pure diesel (noted as D100). Further, the number concentration and volume concentration of ultrafine particles decrease significantly while NOX emissions increase a little with the addition of n-butanol. When the exhaust gas is induced into cylinder, NOX emissions significantly decrease and ultrafine… More
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