Home / Journals / ENERGY / Vol.120, No.2, 2023

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In this research, a single flash geothermal cycle and a trans-critical carbon dioxide cycle to recover the waste heat of the geothermal cycle, are investigated. After modeling the proposed system in EES software, the genetic algorithm and the Nelder-Mead simplex method are used to optimize the "exergy efficiency" parameter as one of the most important output parameters of the system. The output results show that the genetic algorithm provides a more optimal value for the exergy efficiency of the entire system. In the final step of the study, the exergy destruction of different components of the proposed system is calculated.
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  • Open Access

    ARTICLE

    Optimization of a Single Flash Geothermal Power Plant Powered by a Trans-Critical Carbon Dioxide Cycle Using Genetic Algorithm and Nelder-Mead Simplex Method

    Yashar Aryanfar1,*, Jorge Luis García Alcaraz2
    Energy Engineering, Vol.120, No.2, pp. 263-275, 2023, DOI:10.32604/ee.2023.022587
    (This article belongs to this Special Issue: Geothermal Power Generation: Energy, Exergy and Optimization)
    Abstract The usage of renewable energies, including geothermal energy, is expanding rapidly worldwide. The low efficiency of geothermal cycles has consistently highlighted the importance of recovering heat loss for these cycles. This paper proposes a combined power generation cycle (single flash geothermal cycle with trans-critical CO2 cycle) and simulates in the EES (Engineering Equation Solver) software. The results show that the design parameters of the proposed system are significantly improved compared to the BASIC single flash cycle. Then, the proposed approach is optimized using the genetic algorithm and the Nelder-Mead Simplex method. Separator pressure, steam turbine output pressure, and CO2 turbine… More >

    Graphic Abstract

    Optimization of a Single Flash Geothermal Power Plant Powered by a Trans-Critical Carbon Dioxide Cycle Using Genetic Algorithm and Nelder-Mead Simplex Method

  • Open Access

    ARTICLE

    The Non-Singular Fast Terminal Sliding Mode Control of Interior Permanent Magnet Synchronous Motor Based on Deep Flux Weakening Switching Point Tracking

    Xiangfei Li, Yang Yin, Yang Zhou, Wenchang Liu, Kaihui Zhao*
    Energy Engineering, Vol.120, No.2, pp. 277-297, 2023, DOI:10.32604/ee.2023.022461
    Abstract This paper presents a novel non-singular fast terminal sliding mode control (NFTSMC) based on the deep flux weakening switching point tracking method in order to improve the control performance of permanent interior magnet synchronous motor (IPMSM) drive systems. The mathematical model of flux weakening (FW) control is established, and the deep flux weakening switching point is calculated accurately by analyzing the relationship between the torque curve and voltage decline curve. Next, a second-order NFTSMC is designed for the speed loop controller to ensure that the system converges to the equilibrium state in finite time. Then, an extended sliding mode disturbance… More >

    Graphic Abstract

    The Non-Singular Fast Terminal Sliding Mode Control of Interior Permanent Magnet Synchronous Motor Based on Deep Flux Weakening Switching Point Tracking

  • Open Access

    ARTICLE

    A Double-Ended Protection Principle for an LCC-VSC-MTDC System with Strong Anti-Interference Ability

    Chuanjian Wu, Dahai Zhang*, Jinghan He
    Energy Engineering, Vol.120, No.2, pp. 299-316, 2023, DOI:10.32604/ee.2023.023532
    Abstract The DC grid technology of multi-power supply and multi-drop-point power reception is an effective solution for large-scale renewable energy integration into the power grid. Line-commutated converter-Voltage source converter (LCC-VSC) power grids are one of the more important developmental directions of the future power grid that have occured in recent years. But the multi-terminal high voltage direct current system has the problems of inconsistent boundary characteristics, inconsistent control, and fault response characteristics, which puts higher requirements on the protection scheme. Thus, a completely new protection principle is proposed in this paper. Firstly, the fault characteristics of distributed capacitance current are analyzed.… More >

  • Open Access

    ARTICLE

    Optimal Scheduling Method of Cogeneration System with Heat Storage Device Based on Memetic Algorithm

    Haibo Li1,*, Yibao Wang1, Xinfu Pang1, Wei Liu1, Xu Zhang2
    Energy Engineering, Vol.120, No.2, pp. 317-343, 2023, DOI:10.32604/ee.2023.023715
    Abstract Electric-heat coupling characteristics of a cogeneration system and the operating mode of fixing electricity with heat are the main reasons for wind abandonment during the heating season in the Three North area. To improve the wind-power absorption capacity and operating economy of the system, the structure of the system is improved by adding a heat storage device and an electric boiler. First, aiming at the minimum operating cost of the system, the optimal scheduling model of the cogeneration system, including a heat storage device and electric boiler, is constructed. Second, according to the characteristics of the problem, a cultural gene… More >

  • Open Access

    ARTICLE

    Evaluation of Process and Economic Feasibility of Implementing a Topping Cycle Cogeneration

    Unique Karki*, Bhaskaran Gopalakrishnan
    Energy Engineering, Vol.120, No.2, pp. 345-365, 2023, DOI:10.32604/ee.2023.025600
    Abstract Industrial applications that require steam for their end-use generally utilize steam boilers that are typically oversized, citing operations flexibility. Similarly, gas turbine-based power plants corroborate a gas turbine system that may eventually relieve the usable exhaust into the atmosphere. This study explores the economic and technical feasibility of a topping cycle combined heat and power (CHP) system. It does so by leveraging a partially loaded boiler or gas turbine by increasing its unused load to generate steam and heat for subsequent usage. To this end, a decision support tool (COGENTEC) was developed, which emulates a given facility’s boiler or gas-turbine… More >

    Graphic Abstract

    Evaluation of Process and Economic Feasibility of Implementing a Topping Cycle Cogeneration

  • Open Access

    ARTICLE

    Location and Capacity Determination Method of Electric Vehicle Charging Station Based on Simulated Annealing Immune Particle Swarm Optimization

    Jiulong Sun1, Yanbo Che1,*, Ting Yang1, Jian Zhang2, Yibin Cai1
    Energy Engineering, Vol.120, No.2, pp. 367-384, 2023, DOI:10.32604/ee.2023.023661
    Abstract As the number of electric vehicles (EVs) continues to grow and the demand for charging infrastructure is also increasing, how to improve the charging infrastructure has become a bottleneck restricting the development of EVs. In other words, reasonably planning the location and capacity of charging stations is important for development of the EV industry and the safe and stable operation of the power system. Considering the construction and maintenance of the charging station, the distribution network loss of the charging station, and the economic loss on the user side of the EV, this paper takes the node and capacity of… More >

    Graphic Abstract

    Location and Capacity Determination Method of Electric Vehicle Charging Station Based on Simulated Annealing Immune Particle Swarm Optimization

  • Open Access

    REVIEW

    A Survey of the Researches on Grid-Connected Solar Power Generation Systems and Power Forecasting Methods Based on Ground-Based Cloud Atlas

    Xing Deng1,2, Feipeng Da1,*, Haijian Shao2, Xia Wang3
    Energy Engineering, Vol.120, No.2, pp. 385-408, 2023, DOI:10.32604/ee.2023.023480
    Abstract Photovoltaic power generating is one of the primary methods of utilizing solar energy resources, with large-scale photovoltaic grid-connected power generation being the most efficient way to fully utilize solar energy. In order to provide reference strategies for pertinent researchers as well as potential implementation, this paper tries to provide a survey investigation and technical analysis of machine learning-related approaches, statistical approaches and optimization techniques for solar power generation and forecasting. Deep learning-related methods, in particular, can theoretically handle arbitrary nonlinear transformations through proper model structural design, such as hidden layer topology optimization and objective function analysis to save information that… More >

    Graphic Abstract

    A Survey of the Researches on Grid-Connected Solar Power Generation Systems and Power Forecasting Methods Based on Ground-Based Cloud Atlas

  • Open Access

    REVIEW

    Overview of the Global Electricity System in Oman Considering Energy Demand Model Forecast

    Ahmed Al-Abri1, Kenneth E. Okedu1,2,*
    Energy Engineering, Vol.120, No.2, pp. 409-423, 2023, DOI:10.32604/ee.2023.020375
    Abstract Lately, in modern smart power grids, energy demand for accurate forecast of electricity is gaining attention, with increased interest of research. This is due to the fact that a good energy demand forecast would lead to proper responses for electricity demand. In addition, proper energy demand forecast would ensure efficient planning of the electricity industry and is critical in the scheduling of the power grid capacity and management of the entire power network. As most power systems are been deregulated and with the rapid introduction and development of smart-metering technologies in Oman, new opportunities may arise considering the efficiency and… More >

    Graphic Abstract

    Overview of the Global Electricity System in Oman Considering Energy Demand Model Forecast

  • Open Access

    ARTICLE

    Operation State of the Wind Turbine Pitch System Based on Fuzzy Comprehensive Evaluation

    Anfeng Zhu1, Qiancheng Zhao1,*, Lin Gui1, Tianlong Yang1, Xuebing Yang2
    Energy Engineering, Vol.120, No.2, pp. 425-444, 2023, DOI:10.32604/ee.2023.023049
    (This article belongs to this Special Issue: Wind Energy Development and Utilization)
    Abstract To ensure wind turbine (WT) safe operations and improve the utilization rate of wind energy, effective evaluation of the operation state of the pitch system is critical. Therefore, a new method was proposed to evaluate the operation state of the pitch system of WT based on fuzzy comprehensive evaluation. Firstly, based on SCADA data, the working state of the pitch system under rated power state and power state of WT were analyzed. Secondly, through the analysis of characteristic parameters and physical mechanism of the pitch system, the consistency principle of characteristic parameters, the stability principle of power under rated state,… More >

  • Open Access

    ARTICLE

    Displacement Field Variable Modeling Method for Heterogeneous Materials in Wind Power Blade Core Plates

    Ying He, Yongshuang Wen*, Xuemei Huang, Leian Zhang, Rujun Song, Chang Li
    Energy Engineering, Vol.120, No.2, pp. 445-459, 2023, DOI:10.32604/ee.2022.022223
    Abstract In order to study the mechanical properties of the heterogeneous core plate of the wind turbine blade, a modeling method of the core plate based on displacement field variables is proposed. Firstly, the wind turbine blade core plate was modeled according to the theory of modeling heterogeneous material characteristics. Secondly, the three-point bending finite element model of the wind turbine blade core plate was solved by the display dynamic equation to obtain the deformation pattern and force-deformation relationship of the core plate. Finally, the three-point bending static test was conducted to compare with the finite element analysis. The test results… More >

  • Open Access

    ARTICLE

    Modeling Energy Consumption in the Production Processes of Industrial Units Based on Load Response Programs in the Energy Market

    Baodong Li*
    Energy Engineering, Vol.120, No.2, pp. 461-481, 2023, DOI:10.32604/ee.2022.021877
    (This article belongs to this Special Issue: Application of Artificial Intelligence for Energy and City Environmental Sustainability)
    Abstract The optimal operation of microgrids is of great significance for the sake of efficient and economical management of its energy resources. The microgrid energy management system should plan to operate the microgrid while simultaneously considering the electric and thermal load. The present study proposes energy management to minimize the costs of operating an industrial microgrid. In fact, planning for energy supply is among the critical issues that distribution companies deal with daily in the competitive environment. A distribution company usually meets customer (end customer) demands by purchasing energy from a wholesale market. Given the load curtailment, distribution companies have more… More >

  • Open Access

    ARTICLE

    Numerical Simulation of Contamination Accumulation Characteristics of Composite Insulators in Salt Fog Environment

    Yukun Lv, Zeze Chen*, Quanzhi Ge, Qian Wang, Yazhao Zhang
    Energy Engineering, Vol.120, No.2, pp. 483-499, 2023, DOI:10.32604/ee.2023.023649
    Abstract To investigate the fouling characteristics of the composite insulator surface under the salt fog environment, the FXBW-110/120-2 composite insulator was taken as the research object. Based on the field-induced charge mechanism, the multi-physical field coupling software COMSOL was used to numerically simulate the fouling characteristics, explored the calculation method of ESDD, and demonstrated its rationality. Based on this method, the pollution characteristics of the composite insulator under the pollution fog environment were studied, and the influence of wind speed, droplet size, and voltage type on the pollution characteristics of the composite insulator was analyzed. The results showed that: with the… More >

    Graphic Abstract

    Numerical Simulation of Contamination Accumulation Characteristics of Composite Insulators in Salt Fog Environment

  • Open Access

    ARTICLE

    Influence of Wind Turbine Structural Parameters on Wind Shear and Tower Shadow Effect

    Yajing Zhang1, Chaoyang Song2, Zhiguo Li2,*
    Energy Engineering, Vol.120, No.2, pp. 501-510, 2023, DOI:10.32604/ee.2022.021423
    (This article belongs to this Special Issue: Wind Energy Development and Utilization)
    Abstract To overcome the problems of natural decreases in power quality, and to eliminate wind speed fluctuation due to wind shear and tower shadow effect arising from wind turbine structural parameters, an improved prediction model accounting for the dual effect of wind shear and tower shadow is, in this paper, built. Compared to the conventional prediction model, the proposed model contains a new constraint condition, which makes the disturbance term caused by the tower shadow effect always negative so that the prediction result is closer to the actual situation. Furthermore, wind turbine structural parameters such as hub height, rotor diameter, the… More >

    Graphic Abstract

    Influence of Wind Turbine Structural Parameters on Wind Shear and Tower Shadow Effect

  • Open Access

    ARTICLE

    Energy Loss Analysis of Distributed Rooftop Photovoltaics in Industrial Parks

    Yu Xiao1,2, Kai Li1,2, Hongqiao Huang1,2, Haibo Tan1,2, Hua Li3,*
    Energy Engineering, Vol.120, No.2, pp. 511-527, 2023, DOI:10.32604/ee.2023.022750
    (This article belongs to this Special Issue: Key Technologies of Renewable Energy Consumption and Optimal Operation under "Dual Carbon Targets")
    Abstract The analysis of the loss of distributed photovoltaic power generation systems involves the interests of energy users, energy-saving service companies, and power grid companies, so it has always been the focus of the industry and society in some manner or another. However, the related analysis for an actual case that considers different cooperative corporations’ benefits is lacking in the presently available literature. This paper takes the distributed rooftop photovoltaic power generation project in an industrial park as the object, studies the analysis and calculation methods of line loss and transformer loss, analyzes the change of transformer loss under different temperatures… More >

  • Open Access

    ARTICLE

    Title Supersonic Condensation and Separation Characteristics of CO2-Rich Natural Gas under Different Pressures

    Yong Zheng1, Lei Zhao1, Yujiang Wang1, Feng Chang1, Weijia Dong2,*, Xinying Liu2, Yunfei Li2, Xiaohan Zhang2, Ziyuan Zhao3
    Energy Engineering, Vol.120, No.2, pp. 529-540, 2023, DOI:10.32604/ee.2023.022765
    (This article belongs to this Special Issue: Multiphase Flow Theory in Oil and Gas Gathering and Transportation Process)
    Abstract Supersonic separation technology is a new natural gas sweetening method for the treatment of natural gas with high CO2 (carbon dioxide) content. The structures of the Laval nozzle and the supersonic separator were designed, and the mathematical models of supersonic condensation and swirling separation for CO2-CH4 mixture gas were established. The supersonic condensation characteristics of CO2 in natural gas and the separation characteristics of condensed droplets under different inlet pressures were studied. The results show that higher inlet pressure results in a larger droplet radius and higher liquid phase mass fraction; additionally, the influence of centrifugal force is more pronounced,… More >

  • Open Access

    ARTICLE

    Energy Management and Capacity Optimization of Photovoltaic, Energy Storage System, Flexible Building Power System Considering Combined Benefit

    Chang Liu1, Bo Luo1, Wei Wang1, Hongyuan Gao1, Zhixun Wang2, Hongfa Ding3,*, Mengqi Yu4, Yongquan Peng5
    Energy Engineering, Vol.120, No.2, pp. 541-559, 2023, DOI:10.32604/ee.2022.022610
    (This article belongs to this Special Issue: Energy Systems Management and Climate Change)
    Abstract Building structures themselves are one of the key areas of urban energy consumption, therefore, are a major source of greenhouse gas emissions. With this understood, the carbon trading market is gradually expanding to the building sector to control greenhouse gas emissions. Hence, to balance the interests of the environment and the building users, this paper proposes an optimal operation scheme for the photovoltaic, energy storage system, and flexible building power system (PEFB), considering the combined benefit of building. Based on the model of conventional photovoltaic (PV) and energy storage system (ESS), the mathematical optimization model of the system is proposed… More >

  • Open Access

    ARTICLE

    Determination of Effectiveness of Energy Management System in Buildings

    Vivash Karki1, Roseline Mostafa2, Bhaskaran Gopalakrishnan2,*, Derek R. Johnson3
    Energy Engineering, Vol.120, No.2, pp. 561-586, 2023, DOI:10.32604/ee.2023.025218
    Abstract Building Energy Management Systems (BEMS) are computer-based systems that aid in managing, controlling, and monitoring the building technical services and energy consumption by equipment used in the building. The effectiveness of BEMS is dependent upon numerous factors, among which the operational characteristics of the building and the BEMS control parameters also play an essential role. This research develops a user-driven simulation tool where users can input the building parameters and BEMS controls to determine the effectiveness of their BEMS. The simulation tool gives the user the flexibility to understand the potential energy savings by employing specific BEMS control and help… More >

    Graphic Abstract

    Determination of Effectiveness of Energy Management System in Buildings

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