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Yashar Aryanfar^1,*, Jorge Luis García Alcaraz²
Energy Engineering, Vol.120, No.2, pp. 263-275, 2023, DOI:10.32604/ee.2023.022587
（This article belongs to the 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 >

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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 >

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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 >

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411

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Haibo Li^1,*, 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 >

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377

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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 >

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Jiulong Sun¹, Yanbo Che^1,*, 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 >

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Xing Deng^1,2, Feipeng Da^1,*, 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 >

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Ahmed Al-Abri¹, Kenneth E. Okedu^1,2,*
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 >

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Anfeng Zhu¹, Qiancheng Zhao^1,*, 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 the 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 >

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376

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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 >

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Baodong Li^*
Energy Engineering, Vol.120, No.2, pp. 461-481, 2023, DOI:10.32604/ee.2022.021877
（This article belongs to the 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 >

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355

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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 >

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Yajing Zhang¹, Chaoyang Song², Zhiguo Li^2,*
Energy Engineering, Vol.120, No.2, pp. 501-510, 2023, DOI:10.32604/ee.2022.021423
（This article belongs to the 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 >

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Yu Xiao^1,2, Kai Li^1,2, Hongqiao Huang^1,2, Haibo Tan^1,2, Hua Li^3,*
Energy Engineering, Vol.120, No.2, pp. 511-527, 2023, DOI:10.32604/ee.2023.022750
（This article belongs to the Special Issue: Key Technologies of Renewable Energy Consumption and Optimal Operation under )
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 >

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Yong Zheng¹, Lei Zhao¹, Yujiang Wang¹, Feng Chang¹, Weijia Dong^2,*, 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 the 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 >

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Chang Liu¹, Bo Luo¹, Wei Wang¹, Hongyuan Gao¹, Zhixun Wang², Hongfa Ding^3,*, Mengqi Yu⁴, Yongquan Peng⁵
Energy Engineering, Vol.120, No.2, pp. 541-559, 2023, DOI:10.32604/ee.2022.022610
（This article belongs to the 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 >

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Vivash Karki¹, Roseline Mostafa², Bhaskaran Gopalakrishnan^2,*, 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 >

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