Open Access
ARTICLE
Saman Taheri1, Behnam Talebjedi2,*, Timo Laukkanen2
Energy Engineering, Vol.118, No.6, pp. 1577-1594, 2021, DOI:10.32604/EE.2021.017795
Abstract Load forecasting is critical for a variety of applications in modern energy systems. Nonetheless, forecasting is a difficult task because electricity load profiles are tied with uncertain, non-linear, and non-stationary signals. To address these issues, long short-term memory (LSTM), a machine learning algorithm capable of learning temporal dependencies, has been extensively integrated into load forecasting in recent years. To further increase the effectiveness of using LSTM for demand forecasting, this paper proposes a hybrid prediction model that incorporates LSTM with empirical mode decomposition (EMD). EMD algorithm breaks down a load time-series data into several sub-series called intrinsic mode functions (IMFs).… More >
Open Access
ARTICLE
Saif S. Hasan1, Ali Sh. Baqir1, Hameed B. Mahood2,*
Energy Engineering, Vol.118, No.6, pp. 1595-1609, 2021, DOI:10.32604/EE.2021.017433
Abstract In the present study, the effect of injecting air bubble size on the thermal performance of a vertical counter-current shell and coiled tube heat exchanger is experimentally investigated. The experiments were accomplished in a cylindrical shape heat exchanger with a 50 cm height and 15 cm outer diameter. Copper coil with 3.939 m equivalent length and 0.6 cm outer diameter was used to carry the hot fluid (water). Four different cold fluid (shell side) flow rates under laminar flow conditions (316 ≤ Re ≤ 1223), constant hot (coil side) flow rate fluid rates , four different injected air flow rates , invariant… More >
Open Access
REVIEW
Lei Wang1, Zekun Wang2,3,4,*, Yingjian Yang2, Shuni Zhou5, Yehong Dong5, Fanghong Zhang5
Energy Engineering, Vol.118, No.6, pp. 1611-1626, 2021, DOI:10.32604/EE.2021.016010
Abstract China has abundant wind energy resources and huge development potential among developing countries. Japan is a developed country that planned to increase the use of renewable energy, especially wind energy. This research is aimed at reviewing the development of wind power and relevant policies between China and Japan. Firstly, we introduced the current status of global wind power development, such as the global installed capacity of wind power. The annual development of wind power generation in China and Japan is compared, and the distribution characteristics of wind resources are compared. Furthermore, the market share in China and Japan is introduced.… More >
Open Access
ARTICLE
Zhen Liu1,3, Jianwen Wang1,2,*, Fuzhong Bai3, Caifeng Wen1,2, Yunchao Du1
Energy Engineering, Vol.118, No.6, pp. 1627-1640, 2021, DOI:10.32604/EE.2021.016357
（This article belongs to this Special Issue: Wind Energy Development and Utilization)
Abstract The yaw of the horizontal axis wind turbine results in the deflection of the wake flow field of the tower. The reasonable layout of wind farm can reduce the power loss of the downstream wind turbine generators due to the blocking effect of the upstream wake flow and increase the output power of the whole wind farm. However, there is still much space for further research. In this paper, experimental research is conducted on the near-wake deflection characteristics of wind turbine tower under yaw state, expecting the effect of throwing away a brick in order to get a gem. In… More >
Open Access
ARTICLE
Zekun Wang1,2,4, Yan Jia1,2,3,*, Yingjian Yang1, Chang Cai4,5, Yinpeng Chen1
Energy Engineering, Vol.118, No.6, pp. 1641-1658, 2021, DOI:10.32604/EE.2021.017464
（This article belongs to this Special Issue: Wind Energy Development and Utilization)
Abstract Due to the uncertainty of renewable energy power generation and the non-linearity of load demand, it becomes complicated to determine the capacity of each device in hybrid renewable energy power generation systems. This work aims to optimize the capacity of two types of the off-grid hybrid wind-hydrogen energy system. We considered the maximum profit of the system and the minimum loss of power supply probability as optimization goals. Firstly, we established steady-state models of the wind turbine, alkaline electrolyzer, lead-acid battery, and proton exchange membrane fuel cell in matrix laboratory software to optimize the capacity. Secondly, we analyzed the operating… More >
Open Access
ARTICLE
Sheikh Hassan1, Didarul Ahasan Redwan1, Md. Mamun Molla1,2,*, Sharaban Thohura3, M. Abu Taher4, Sadia Siddiqa5
Energy Engineering, Vol.118, No.6, pp. 1659-1679, 2021, DOI:10.32604/EE.2021.017657
Abstract A two-dimensional (2D) laminar flow of nanofluids confined within a square cavity having localized heat source at the bottom wall has been investigated. The governing Navier–Stokes and energy equations have been non dimensionalized using the appropriate non dimensional variables and then numerically solved using finite volume method. The flow was controlled by a range of parameters such as Rayleigh number, length of heat source and nanoparticle volume fraction. The numerical results are represented in terms of isotherms, streamlines, velocity and temperature distribution as well as the local and average rate of heat transfer. A comparative study has been conducted for… More >
Open Access
ARTICLE
Ahmed Abubakar Elwan*, Mohammed Hafiz Habibuddin
Energy Engineering, Vol.118, No.6, pp. 1681-1701, 2021, DOI:10.32604/EE.2021.016291
Abstract With population growth around the world, municipal waste disposal and continued energy demand becomes some of the major challenges to deal with. In order to address these, an approach is required for an optimal waste management system that offers the population benefit with a lower environmental impact. This study evaluates the technical-economic and environmental impact analysis of a grid-connected waste to energy (WtE) plant to power a Univerisiti Teknologi Malaysia (UTM) community. The energy recovery potential of the waste stream was assessed using the life cycle assessment (LCA) method with GaBiTM software (version 4). A technical, economic and environmental analysis… More >
Open Access
ARTICLE
Fuyun Zhu, Guoqing Wu*
Energy Engineering, Vol.118, No.6, pp. 1703-1712, 2021, DOI:10.32604/EE.2021.015602
（This article belongs to this Special Issue: Advances in Modern Electric Power and Energy Systems)
Abstract Accurate power load forecasting plays an important role in the power dispatching and security of grid. In this paper, a mathematical model for power load forecasting based on the random forest regression (RFR) was established. The input parameters of RFR model were determined by means of the grid search algorithm. The prediction results for this model were compared with those for several other common machine learning methods. It was found that the coefficient of determination (R2) of test set based on the RFR model was the highest, reaching 0.514 while the corresponding mean absolute error (MAE) and the mean squared… More >
Open Access
ARTICLE
Bo Zeng*, Yixian Liu, Yangfan Luo
Energy Engineering, Vol.118, No.6, pp. 1713-1728, 2021, DOI:10.32604/EE.2021.016678
（This article belongs to this Special Issue: Advances in Modern Electric Power and Energy Systems)
Abstract In the future smart cities, parking lots (PLs) can accommodate hundreds of electric vehicles (EVs) at the same
time. This trend creates an opportunity for PLs to serve as a potential flexibility resource, considering growing
penetration of EVs and integration of distributed energy resources DER (such as photovoltaic and energy
storages). Given this background, this paper proposes a comprehensive evaluation framework to investigate
the potential role of DER-integrated PLs (DPL) with the capability of vehicle-to-grid (V2G) in improving the
reliability of the distribution network. For this aim, first, an overview for the distribution system with DPLs is
provided. Then, a… More >
Open Access
ARTICLE
Xiaojuan Lu, Qingbo Zhang*
Energy Engineering, Vol.118, No.6, pp. 1729-1740, 2021, DOI:10.32604/EE.2021.014938
Abstract In the process of grid-connected photovoltaic power generation, there are high requirements for the quality of the power that the inverter breaks into the grid. In this work, to improve the power quality of the grid-connected inverter into the grid, and the output of the system can meet the grid-connected requirements more quickly and accurately, we exhibit an approach toward establishing a mixed logical dynamical (MLD) model where logic variables were introduced to switch dynamics of the single-phase photovoltaic inverters. Besides, based on the model, our recent efforts in studying the finite control set model predictive control (FCS-MPC) and devising… More >
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