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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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 >
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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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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 >
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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 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 >
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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 >
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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 >
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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 >
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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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