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Himanshu¹, Kunwar Pal², Sanjeev Jain³, S. K. Tyagi^1,*
Energy Engineering, Vol.118, No.5, pp. 1237-1251, 2021, DOI:10.32604/EE.2021.016489
Abstract A disruptive approach to a fundamental process has been applied in a biomass combustion device with two variable speed fans to supply air for gasification and another for combustion processes, separately. Besides, the preheating of secondary air, required for combustion process was also ensured through annulus chamber before being fed into the combustion chamber. The turbulent flow and homogenous mixing were also ensured by controlling the flow rate resulting in the reduced emissions of carbon monoxide (CO) and fine particulate matter (PM 2.5, particulate matter having aerodynamic diameter <2.5 micron). The design approach applied here has also ensured the homogeneous… More >

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I. Samylingam¹, Navid Aslfattahi², K. Kadirgama^1,*, Mahendran Samykano³, L. Samylingam⁴, R. Saidur^4,5
Energy Engineering, Vol.118, No.5, pp. 1253-1265, 2021, DOI:10.32604/EE.2021.016087
（This article belongs to the Special Issue: Advanced Materials and Technologies for Sustainable Energy)
Abstract In this study, nanocomposite of ternary nitrate molten salt induced with MXene is developed. LiNO₃-NaNO₃-KNO₃ with wt% of 35:12:53 and 35:10:55 are produced and doped with MXene in the wt% of 0.2, 0.5, 1.0, and 1.5. FTIR result indicates the composites had no chemical reaction occurred during the preparation. UV-VIS analysis shows the absorption enhancement with respect to the concentration of MXene. Thermogravimetric analysis (TGA) was used to measure the thermal stability of the LiNO₃-NaNO₃-KNO₃ induced with MXene. The ternary molten salts were stable at temperature range of 600–700°C. Thermal stability increases with the addition of MXene. 1.5 wt% of… More >

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Zihao Wang, Dunxi Yu^*, Jingkun Han, Jianqun Wu
Energy Engineering, Vol.118, No.5, pp. 1267-1276, 2021, DOI:10.32604/EE.2021.016107
（This article belongs to the Special Issue: Advancement of Understanding of PM_2.5 and Hg Emissions and Their Control Technologies for Cleaner Combustion)
Abstract Typical biomass torrefaction is a mild pyrolysis process under conditions of ordinary pressure, low temperature (200–300°C) and inert atmosphere. Torrefaction is considered to be a competitive technology for biomass pretreatment, but its impacts on the emissions of particulate matter from biomass combustion are worthy of further study. In this paper, three kinds of biomass, i.e., bagasse, wheat straw and sawdust were selected for torrefaction pretreatment and the impacts of torrefaction on the emission characteristics of PM₁₀ from biomass combustion were investigated. The combustion experiments were carried out on a drop tube furnace. The combustion-generated particulate and bulk ash samples were… More >

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Mingyu Yu¹, Mengyuan Liu¹, Guangqian Luo^1,2,*, Ruize Sun¹, Jingyuan Hu¹, Hailu Zhu¹, Li Zhong³, Lipeng Han³, Xian Li¹, Hong Yao¹
Energy Engineering, Vol.118, No.5, pp. 1277-1286, 2021, DOI:10.32604/EE.2021.014810
Abstract The application of forced mercury oxidation technology would lead to an increase of Hg²⁺ concentration in the flue gas. Although Hg²⁺ can be easily removed in the WFGD, the mercury re-emission in the WFGD can decrease the total removal of mercury from coal-fired power plants. Hence, it is necessary to control Hg²⁺ concentration in the devices before the WFGD. Fly ash adsorbent is considered as a potential alternative for commercial activated carbon adsorbent. However, the adsorption efficiency of the original fly ash is low. Modification procedure is needed to enhance the adsorption performance. In this study, the adsorption of Hg²⁺… More >

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Junxiang Jiang^1,2, Shaogang Liu^1,*, Lifeng Feng³
Energy Engineering, Vol.118, No.5, pp. 1287-1303, 2021, DOI:10.32604/EE.2021.015354
Abstract This paper presents a 2DOF nonlinear piezoelectric energy harvester for improving the efficiency of energy harvesting in low frequency range. The device consisted of an L-shaped piezoelectric cantilever with a magnet at the tip of the first beam and two external magnets on the pedestal. The distance between the magnets which generated nonlinear magnetic attraction was adjusted such that the system can exhibit monostable or bistable characteristics. First, the model of this piezoelectric energy harvester was established and the dynamic equation was derived based on the magnetic attractive force. Then, the nonlinear dynamic responses of the system subject to harmonic… More >

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1013

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J. Kananathan^1,2, M. Samykano^2,*, K. Kadirgama³, D. Ramasamy², M. M. Rahman²
Energy Engineering, Vol.118, No.5, pp. 1305-1315, 2021, DOI:10.32604/EE.2021.016131
（This article belongs to the Special Issue: Advanced Materials and Technologies for Sustainable Energy)
Abstract Fused deposition modeling (FDM)-3D printing has been the favored technology to build functional components in various industries. The present study investigates infill percentage and infill pattern effects on the printed parts’ impact properties through the 3D printing technique using coconut wood-filled PLA composites. Mathematical models are also proposed in the present study with the aim for future property prediction. According to the ASTM standard, fifteen specimens with different parameter combinations were printed using a low-cost FDM 3D printer to evaluate their impact properties. Statistical analysis was performed using MINITAB to validate the experimental data and model development. The experimental outcomes… More >

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Vibhushit Gupta¹, Shubham K. Verma², Sanjeev Anand², Navin Gupta³, Yatheshth Anand^1,*
Energy Engineering, Vol.118, No.5, pp. 1317-1331, 2021, DOI:10.32604/EE.2021.016732
Abstract The utilization of energy in building sectors comprises 30–40% of the entire global energy consumption. Most of the energy is being utilized for cooling & heating the buildings. These cooling and heating depend on the nature of climate for different places. In this, the detailed analysis of the building envelope across five areas (viz. Srinagar, Jaisalmer, New Delhi, Thiruvananthapuram and Bangalore) representing different climatic zones had been carried out. Simulations are performed for these locations using eQUEST and ANSYS software. Three of the result output from the eQUEST simulation are used to assess the different cases. These outputs are: total… More >

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Bing Wang^1,2, Kailei Deng¹, Liting He¹, Zhenming Sun^1,*
Energy Engineering, Vol.118, No.5, pp. 1333-1351, 2021, DOI:10.32604/EE.2021.014258
（This article belongs to the Special Issue: Energy Systems Management and Climate Change)
Abstract China has implemented both quantitative and policy incentives for renewable energy development since 2019 and is currently in the policy transition stage. The implementation of renewable portfolio standards (RPSs) is difficult due to the interests of multiple stakeholders, including power generation enterprises, power grid companies, power users, local governments, and the central government. Based on China’s RPS policy and power system reform documents, this research sorted out the core game decision problems of China’s renewable energy industry and established a conceptual game decision model of the renewable energy industry from the perspective of local governments, power generation enterprises and power… More >

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1072

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Pinjie Xie^1,*, Ying Zhai¹, Fan Yang^1,2, Zhuowen Mu³, Chao Wang⁴
Energy Engineering, Vol.118, No.5, pp. 1353-1374, 2021, DOI:10.32604/EE.2021.014970
Abstract Electricity productivity is regarded as a major assessment indicator in the design of energy saving policies, given that China has entered a “New Normal” of economic development. In fact, enhancing electricity productivity in an all-round way, as is one of the binding indicators for energy and environmental issues, means that non-growth target of total electric energy consumption in the economic development is feasible. The Gini coefficient, Theil index, and Mean log deviation are utilized to measure regional differences in China’s electricity productivity from 1997 to 2016 in five regions, and conditional β convergence is empirically analyzed with the spatial Durbin… More >

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817

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Hui Wang, Haocheng Xu^*, Wenhui Zhao
Energy Engineering, Vol.118, No.5, pp. 1375-1394, 2021, DOI:10.32604/EE.2021.014641
Abstract Under the background of implementing renewable portfolio standards and the ever-improving tradable green certificate scheme, the increasingly environmentally-friendly preference of power users is leading to changes in electricity demand, which, in turn, is driving changes in the decision-making behaviors of various actors in the power supply chain. Based on this, with the goal of pursuing maximum profit, consumer-power-demand functions have been introduced with some consideration of the factors of consumer preference to establish an optimal profit model for each trading subject in non-cooperative states of the power supply chain, under the constraints of meeting renewable energy portfolio standards. Here, the… More >

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803

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Doudou Liu^1,*, Liang Qiao^2,3, Feng Zhang⁴, Xueliang Yuan²
Energy Engineering, Vol.118, No.5, pp. 1395-1409, 2021, DOI:10.32604/EE.2021.014697
Abstract The rapid development of urbanization has led to a rapid increase in total energy consumption. The proportion of domestic energy consumption to total energy consumption has gradually increased and has become the major driving force for energy consumption. With the pressure from urbanization and domestic energy consumption, it is necessary to study the impact of urbanization on domestic energy consumption of the regional level and to explore the function paths of these two factors. The findings are helpful to realize sustainable development based on the actual situation analysis, horizontal survey data and statistical yearbook panel data. The current situation and… More >

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1649

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808

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Mahmoud Abdo Tantawy¹, Ahmed A. M. Elgibaly¹, Ahmed Mohamed Farag^2,*
Energy Engineering, Vol.118, No.5, pp. 1411-1423, 2021, DOI:10.32604/EE.2021.016192
Abstract In recent years, many trials have been made to use the Rate Transient Analysis (RTA) techniques as a method to describe the gas condensate reservoirs. The problem with using these techniques is the multi-phase behavior of the gas condensate reservoirs. Therefore, the Pressure Transient Analysis (PTA) is commonly used in this case to analyze the reservoir parameters. In this paper, we are going to compare the results of both PTA and RTA of three wells in gas condensate reservoirs. The comparison showed a great match between the results of the two mentioned techniques for the first time using a reference… More >

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Manar B. AL-Hajji^1,*, Nabeel Abu Shaban², Shahnaz Al Khalil², Ayat Al-Jarrah³
Energy Engineering, Vol.118, No.5, pp. 1425-1438, 2021, DOI:10.32604/EE.2021.016413
Abstract Solar energy is regarded as one of the promising renewable energy sources in the world.The main aim of this study is to use the Taguchi-Grey relational grade analysis to optimize the performance of two Solar Air Heaters (SAHs). A typical Grey–Taguchi method was applied. The Orthogonal Array, Signal-to-Noise ratio, Grey Relational Grade, and Analysis of Variance were employed to investigate the performance characteristics of SAH. Experimental observations were made in agreement with Jordanian climate 32°00′ N latitude and 36°00′ E longitude with a solar intensity of 500 W\m². The operating factors selected for optimization are the tilt angle (T) with… More >

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Dandan Song^1,*, Lianjun Zhou¹, Ziqi Peng², Senhua Luo², Jun Zhu³
Energy Engineering, Vol.118, No.5, pp. 1439-1452, 2021, DOI:10.32604/EE.2021.015011
（This article belongs to the Special Issue: Wind Energy Development and Utilization)
Abstract The axial flux permanent magnet (AFPM) generator with double-sided internal stator structure is highly suitable for vertical axis wind turbines due to its high power density. The performance of the AFPM generator with double-sided internal stator structure can be improved by the reasonable design of electromagnetic parameters. To further improve the overall performance of the AFPM generator with double-sided internal stator structure, multivariable (coil width ω_c, permanent magnet thickness h, pole arc coefficient α_p and working air gap l_g) and multi-objective (generator efficiency η, total harmonic distortion of the voltage THD and induced electromotive force amplitude EMF) functional relationships are… More >

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1115

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Xing Zhang^*
Energy Engineering, Vol.118, No.5, pp. 1453-1467, 2021, DOI:10.32604/EE.2021.015032
Abstract Polymer has been successfully used to enhance crude oil recovery at high water cut stage. However, the application of polymer flooding is limited by the heterogeneity of reservoir. In this work, the role of polymer flooding in heterogeneous reservoir was explored by nuclear magnetic resonance (NMR) spectroscopy. Parallel core displacement experiments were carried out to study polymer flooding in heterogeneous formation. The results showed that the polymer flooding area was related to permeability and pore connectivity. At the end of the water flooding stage, the residual oil was not evenly distributed in porous media. The percent crude oil recovery increased… More >

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978

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Ang Li^1,2, Peng Lei^1,*, Changkun Chen¹, Tong Xu¹
Energy Engineering, Vol.118, No.5, pp. 1469-1482, 2021, DOI:10.32604/EE.2021.015413
Abstract A simplified model for SO₂ generation during spontaneous combustion of coal gangue was put forward and validated using the measured data. Using the proposed model, the effects of initial temperature inside the gangue and fresh air supply on SO₂ generation were discussed. The results showed that, higher initial temperature inside the gangue could accelerate the oxidation rate of FeS₂ and increase the maximum concentration of SO₂. If initial temperature inside the gangue increased by about 37%, the total SO₂ generation increased by 166%. Fresh air supply had less significant effect on the oxidation rate of FeS₂. However, the higher the… More >

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Ahmed J. Hamad^*, Fawziea M. Hussien, Johain J. Faraj
Energy Engineering, Vol.118, No.5, pp. 1483-1497, 2021, DOI:10.32604/EE.2021.016867
（This article belongs to the Special Issue: Advanced Materials and Technologies for Sustainable Energy)
Abstract The fluctuation in drying temperature influences the food products’ quality and drying time significantly during the drying process using an indirect solar dryer. One of the effective methods to reduce these variations in the temperature is based on thermal storage materials to control the drying temperature. An experimental investigation is presented in this study to evaluate the performance of an indirect solar dryer with air double pass using multiple phase change materials (PCM) as thermal storage materials. Two PCMs with different melting points are used to store the available heat energy during peak sunshine periods and reduce the drying temperature… More >

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Bingbing Chen^*, Zhengyi Zhu, Xuyan Wang, Can Zhang
Energy Engineering, Vol.118, No.5, pp. 1499-1514, 2021, DOI:10.32604/EE.2021.015145
（This article belongs to the Special Issue: Advances in Modern Electric Power and Energy Systems)
Abstract To solve the medium and long term power load forecasting problem, the combination forecasting method is further expanded and a weighted combination forecasting model for power load is put forward. This model is divided into two stages which are forecasting model selection and weighted combination forecasting. Based on Markov chain conversion and cloud model, the forecasting model selection is implanted and several outstanding models are selected for the combination forecasting. For the weighted combination forecasting, a fuzzy scale joint evaluation method is proposed to determine the weight of selected forecasting model. The percentage error and mean absolute percentage error of… More >

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Wei Zhang^1,2, Qihui Ling^1,2,*, Qiancheng Zhao^1,2, Hushu Wu³
Energy Engineering, Vol.118, No.5, pp. 1515-1535, 2021, DOI:10.32604/EE.2021.014162
（This article belongs to the Special Issue: Advances in Modern Electric Power and Energy Systems)
Abstract The condition monitoring and fault diagnosis have been identified as the key to achieving higher availabilities of wind turbines. Numerous studies show that the open-circuit fault is a significant contributor to the failures of wind turbine converter. However, the multiple faults combinations and the influence of wind speed changes abruptly, grid voltage sags and noise interference have brought great challenges to fault diagnosis. Accordingly, concerning the open-circuit fault of converters in direct-driven PMSG wind turbine, a diagnostic method for multiple open-circuit faults is proposed in this paper, which is divided into two tasks: The first one is the fault detection… More >

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954

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Jie Chen¹, Wei Zhang¹, Man Ding^2,*, Libin Hu¹, Jinpeng Wang², Chenying Li¹, Jingying Cao¹
Energy Engineering, Vol.118, No.5, pp. 1537-1548, 2021, DOI:10.32604/EE.2021.015439
Abstract The aging characteristics of the XLPE insulation of 110 kV power cables in the initial stage of operation are studied in this paper. The XLPE insulation from cables with different running time was tested by using electrical and physicochemical methods, from which the degradation state of XLPE under multiple stresses during operation was derived. The broadband dielectric spectrum test taken from 10^–1 to 10⁶ Hz showed that the dielectric constant and dielectric loss of the XLPE insulation first decrease and then increase with the increase of cable running time, which show obvious variation until 10 years of operation. The AC… More >

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Dan Wu¹, Yanbo Che¹, Wei Li^2,*, Wei He³, Dongyi Li⁴
Energy Engineering, Vol.118, No.5, pp. 1549-1564, 2021, DOI:10.32604/EE.2021.014818
Abstract With the significant progress of the “coal to electricity” project, the electric kiln equipment began to be connected to the distribution network on a large scale, which caused power quality problems such as low voltage, high harmonic distortion rate, and high reactive power loss. This paper proposes a two-stage power grid comprehensive resource optimization configuration model. A multi-objective optimization solution based on the joint simulation platform of Matlab and OpenDSS is developed. The solution aims to control harmonics and optimize reactive power. In the first stage, a multi-objective optimization model is established to minimize the active network loss, voltage deviation,… More >

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817

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Nugroho Agung Pambudi^1,*, Santiko Wibowo¹, Ranto¹, Lip Huat Saw²
Energy Engineering, Vol.118, No.5, pp. 1565-1576, 2021, DOI:10.32604/EE.2021.016642
Abstract Organic Rankine Cycle (ORC) is one of the solutions to utilize a low temperature geothermal fluid for power generation. The ORC system can be placed at the exit of the separator to extract energy from brine. Furthermore, one of the main components of the system and very important is the pump. Therefore, in this research, the pump rotation is examined to investigate the effect on power output and energy efficiency for low temperature geothermal fluid. The rotation is determined by using an inverter with the following frequencies: 7.5, 10, 12.5, 15 and 17.5 Hz, respectively. R-134 working fluid is employed… More >

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