Energy Engineering

ISSN: 0199-8595 (print)
ISSN: 1546-0118 (online) Publication Frequency: Bi-monthly

About the Journal

Energy Engineering is a bi-monthly peer-reviewed publication. The journal invites researchers, engineers, scientists, technologists, planners, and policy makers to present their original research results and findings on all important energy topics. The topics considered include energy generation, conversion, conservation, utilization, storage, transmission, system, technologies, management, and sustainability. The studies of the impacts of energy use and energy policy are also welcomed.

Indexing and Abstracting

Ei Compendex/Engineering Village (Elsevier); Scopus (Elsevier); WorldCat (OCLC); Google Scholar; ResearchGate; SCImago (SJR); Crossref; Sherpa/RoMEO; Letpub; Elektronische; Genamics JournalSeek; Dimensions; Portico, etc...

Current Issue - Vol.119, No.2, 2022 Most Viewed

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ARTICLE
Impacts of Rotation on Unsteady Fluid Flow and Energy Distribution through a Bending Duct with Rectangular Cross Section
Mohammad Zohurul Islam¹, Rabindra Nath Mondal², Suvash C. Saha^1,*
Energy Engineering, Vol.119, No.2, pp. 453-472, 2022, DOI:10.32604/ee.2022.018160
Abstract
A depth understanding of fluid flow past a curved duct having rectangular cross-section with different aspect ratios (l) are essential for various engineering applications such as in chemical, mechanical, bio-mechanical and bio-medical engineering. So highly ambitious researchers have given significant attention to study new characteristics of fluid flow in a curved duct. The flow characterization in the rectangular duct has been studied over a wide range of numerical and selective experimental studies. However, proper knowledge with the effects of Coriolis force for different aspect ratios is important for better understanding of the transitional behaviour and the subsequent heat generation, which… More
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Identification and Classification of Multiple Power Quality Disturbances Using a Parallel Algorithm and Decision Rules
Nagendra Kumar Swarnkar¹, Om Prakash Mahela², Baseem Khan^3,*, Mahendra Lalwani¹
Energy Engineering, Vol.119, No.2, pp. 473-497, 2022, DOI:10.32604/ee.2022.017703
Abstract A multiple power quality (MPQ) disturbance has two or more power quality (PQ) disturbances superimposed on a voltage signal. A compact and robust technique is required to identify and classify the MPQ disturbances. This manuscript investigated a hybrid algorithm which is designed using parallel processing of voltage with multiple power quality (MPQ) disturbance using stockwell transform (ST) and hilbert transform (HT). This will reduce the computational time to identify the MPQ disturbances, which makes the algorithm fast. A MPQ identification index (IPI) is computed using statistical features extracted from the voltage signal using the ST and HT. IPI has different… More
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HCl-Induced Hg⁰ Transformation over CuMn₂O₄ Sorbent
Aijia Zhang, Yingju Yang, Jing Liu^*, Junyan Ding
Energy Engineering, Vol.119, No.2, pp. 499-510, 2022, DOI:10.32604/ee.2022.015504
（This article belongs to this Special Issue: Advancement of Understanding of PM_2.5 and Hg Emissions and Their Control Technologies for Cleaner Combustion)
Abstract CuMn₂O₄ spinel has been regarded as a highly efficient sorbent for Hg⁰ capture from flue gas. The regenerability and recyclability of CuMn₂O₄ sorbent are mainly associated with the mercury speciation adsorbed on its surface. However, the effect mechanism of HCl on Hg⁰ transformation over CuMn₂O₄ sorbent is still elusive. Experiments were conducted to understand the effect of HCl on Hg⁰ transformation over CuMn₂O₄ sorbent. The results indicate that CuMn₂O₄ sorbent is a mesoporous material and possesses a good thermal stability. CuMn₂O₄ shows >95% Hg⁰ removal efficiency in a wide temperature window of 50–350°C. The favorable electron-transfer environment caused by the… More
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Angle Scattering Method for Soot Concentration Measurement under Ultra-Low Emissions Condition
Bin Yang^1,*, Xingchen Zhu¹, Jie Deng¹, Xiaoxu Guo¹, Jinke Han², Xiaowei Liu²
Energy Engineering, Vol.119, No.2, pp. 511-522, 2022, DOI:10.32604/ee.2022.016079
（This article belongs to this Special Issue: Advancement of Understanding of PM_2.5 and Hg Emissions and Their Control Technologies for Cleaner Combustion)
Abstract Aiming at the problem of soot concentration measurement under ultra-low emission conditions, a forward small angle soot concentration measurement method is proposed. Taking a typical boiler emission of 0.1 μm–3.0 μm bimodal distribution soot as an object, the particle scatter simulation calculation under different parameters is carried out, and the influence of detection angle and particle size on the angular scattering measurement of ultra-low emission soot is analyzed. The influence of detection angle and particle size on the angular scattering measurement of ultra-low emission soot is analyzed. Preferably, the wavelength of incident light is 650 nm, and the forward detection… More
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Protection of Zero-Sequence Power Variation in Mountain Wind Farm Collector Lines Based on Multi-Mode Grounding
Hongchun Shu^1,2, Yaqi Deng^1,2,*, Pulin Cao², Jun Dong², Hongjiang Rao², Zhiqian Bo²
Energy Engineering, Vol.119, No.2, pp. 523-538, 2022, DOI:10.32604/ee.2022.015570
（This article belongs to this Special Issue: Wind Energy Development and Utilization)
Abstract The arc-suppression coil (ASC) in parallel low resistance (LR) multi-mode grounding is adopted in the mountain wind farm to cope with the phenomenon that is misoperation or refusal of zero-sequence protection in LR grounding wind farm. If the fault disappears before LR is put into the system, it is judged as an instantaneous fault; while the fault does not disappear after LR is put into the system, it is judged as a permanent fault; the single-phase grounding fault (SLG) protection criterion based on zero-sequence power variation is proposed to identify the instantaneous-permanent fault. Firstly, the distribution characteristic of zero-sequence voltage… More
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Research on the Impacts of the Inertia and Droop Control Gains from a Variable-Speed Wind Turbine Generator on the Frequency Response
Dejian Yang¹, Yien Xu¹, Tong Zhu¹, Yang Wang¹, Qiuhan Cao¹, Yuang Ma¹, Enshu Jin², Xinsong Zhang^1,*, Haochen Sun^3,*
Energy Engineering, Vol.119, No.2, pp. 539-554, 2022, DOI:10.32604/ee.2022.015133
（This article belongs to this Special Issue: Wind Energy Development and Utilization)
Abstract System frequency must be kept very close to its nominal range to ensure the stability of an electric power grid. Excessive system frequency variations are able to result in load shedding, frequency instability, and even generator damage. With increasing wind power penetration, there is rising concern about the reduction in inertia response and primary frequency control in the electric power grid. Converter-based wind generation is capable of providing inertia response and primary frequency response; nevertheless, the primary frequency and inertia responses of wind generation are different from those of conventional synchronous fleets; it is not completely understood how the primary… More
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Thermogravimetric and Synergy Analysis of the Co-Pyrolysis of Coconut Husk and Laminated Plastic Packaging for Biofuel Production
Joselito Olalo^*
Energy Engineering, Vol.119, No.2, pp. 555-567, 2022, DOI:10.32604/EE.2022.018864
Abstract Unlike plastic, biomass can also be converted and produce high quality of biofuel. Co-pyrolysis of coconut husk (CH) and laminated plastic packaging (LPP) were done in this study. Synergy between these two feedstock was calculated by using thermogravimetric (TGA) and derivative thermogravimetry (DTG) analysis. Different activation energies of the reactions in the co-pyrolysis of CH and LPP were evaluated using the Coats-Redfern method. Results showed an activation energy ranging from 8 to 37 kJ/mol in the different percentage composition of the co-pyrolysis. Also, thermal degradation happens in two-stages in the copyrolysis of CH and LPP, in which CH degrades at… More
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Multifunction Battery Energy Storage System for Distribution Networks
Omar H. Abdalla^1,*, Gamal Abdel-Salam², Azza A. A. Mostafa³
Energy Engineering, Vol.119, No.2, pp. 569-589, 2022, DOI:10.32604/ee.2022.018693
（This article belongs to this Special Issue: Advances in Modern Electric Power and Energy Systems)
Abstract Battery Energy Storage System (BESS) is one of the potential solutions to increase energy system flexibility, as BESS is well suited to solve many challenges in transmission and distribution networks. Examples of distribution network’s challenges, which affect network performance, are: (i) Load disconnection or technical constraints violation, which may happen during reconfiguration after fault, (ii) Unpredictable power generation change due to Photovoltaic (PV) penetration, (iii) Undesirable PV reverse power, and (iv) Low Load Factor (LF) which may affect electricity price. In this paper, the BESS is used to support distribution networks in reconfiguration after a fault, increasing Photovoltaic (PV) penetration,… More
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A Dual Arm Complementary Hybrid Modulation Strategy Combining NL-SPWM for MMC Applications
Mingwan Mei¹, Ping Wang¹, Yanbo Che^1,*, Zihan Lv¹, Zmarrak Wali Khanand¹, Chao Xing^1,2
Energy Engineering, Vol.119, No.2, pp. 591-607, 2022, DOI:10.32604/ee.2022.016585
（This article belongs to this Special Issue: Advances in Modern Electric Power and Energy Systems)
Abstract
In the medium voltage direct current (MVDC) transmission system, a small number of MMC sub modules will reduce the power quality. In this paper, based on the research background of Photovoltaic Medium Voltage Direct Current (PV-MVDC) system, a Hybrid Modulation Strategy based on the Decoupled Double Synchronous Reference Frame (DDSRF) control strategy is proposed. The dual arm complementary hybrid modulation combining nearest-level-SPWM (NL-SPWM) can keep the number of SMs in the ON state constant. Then, the corresponding voltage sharing control algorithm of sub module (SM) is introduced. Through theoretical calculation, the modulation strategy can be found to stabilize the DC… More
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Coordinated Control Strategy for Harmonic Compensation of Multiple Active Power Filters
Jianfeng Yang^*, Rende Qi^*, Yang Liu, Yu Ding
Energy Engineering, Vol.119, No.2, pp. 609-620, 2022, DOI:10.32604/ee.2022.016969
（This article belongs to this Special Issue: Advances in Modern Electric Power and Energy Systems)
Abstract In order to minimize the harmonic distortion rate of the current at the common coupling point, this paper proposes a coordinated allocation strategy of harmonic compensation capacity considering the performance of active power filters (APF). On the premise of proportional distribution of harmonic compensation capacity, the harmonic compensation rate of each APF is considered, and the harmonic current value of each APF to be compensated is obtained. At the same time, the communication topology is introduced. Each APF takes into account the compensation ability of other APFs. Finally, three APFs with different capacity and performance are configured at the harmonic… More
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A Fault Current Limiting Hybrid DC Circuit Breaker
Lei Huang^*, Qian Zhang, Wenlei Liu, Ruixue Liu
Energy Engineering, Vol.119, No.2, pp. 621-636, 2022, DOI:10.32604/ee.2022.016769
（This article belongs to this Special Issue: Advances in Modern Electric Power and Energy Systems)
Abstract Due to the low impedance characteristic of the high voltage direct current (HVDC) grid, the fault current rises extremely fast after a DC-side fault occurs, and this phenomenon seriously endangers the safety of the HVDC grid. In order to suppress the rising speed of the fault current and reduce the current interruption requirements of the main breaker (MB), a fault current limiting hybrid DC circuit breaker (FCL-HCB) has been proposed in this paper, and it has the capability of bidirectional fault current limiting and fault current interruption. After the occurrence of the overcurrent in the HVDC grid, the current limiting… More
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Analysis of Power Quality Problems in Large-Scale Application of Air-Source Heat Pump
Zhihao Zheng¹, Yanbo Che^1,*, Hailian Bi¹, Dan Wu¹, Wei He²
Energy Engineering, Vol.119, No.2, pp. 637-651, 2022, DOI:10.32604/ee.2022.016661
（This article belongs to this Special Issue: Advanced Heat Pump Technologies for Renewable Energy Utilization)
Abstract With the implementation of electric energy alternatives, the large-scale application of electric energy substitution represented by air-source heat pumps has replaced traditional coal-fired heating, which is beneficial for the environment and alleviates air pollution. However, the large-scale application of air-source heat pumps has brought power quality problems such as voltage sags, harmonic pollution, and three-phase imbalance to the distribution network. This paper studies the fixed-frequency and variable-frequency air-source heat pump, introduces its working principle, analyzes the mechanism of its power quality problem. Moreover, the paper establishes a simulation model for the fixed-frequency heat pump and variable-frequency heat pump to connect… More
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Two Phase Flow Simulation of Fractal Oil Reservoir Based on Meshless Method
Xian Zhou¹, Fei Wang², Ziyu Wang³, Yunfeng Xu^1,*
Energy Engineering, Vol.119, No.2, pp. 653-664, 2022, DOI:10.32604/ee.2022.019072
（This article belongs to this Special Issue: Simulation of Flow and Transport Problems in Petroleum Engineering)
Abstract The reservoir is the networked rock skeleton of an oil and gas trap, as well as the generic term for the fluid contained within pore fractures and karst caves. Heterogeneity and a complex internal pore structure characterize the reservoir rock. By introducing the fractal permeability formula, this paper establishes a fractal mathematical model of oil-water two-phase flow in an oil reservoir with heterogeneity characteristics and numerically solves the mathematical model using the weighted least squares meshless method. Additionally, the method’s correctness is verified by comparison to the exact solution. The numerical results demonstrate that the fractal oil-water two-phase flow mathematical… More
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Bearing Fault Diagnosis Method of Wind Turbine Based on Improved Anti-Noise Residual Shrinkage Network
Xiaolei Li^*
Energy Engineering, Vol.119, No.2, pp. 665-680, 2022, DOI:10.32604/ee.2022.019292
（This article belongs to this Special Issue: Advancements in Renewable Energy Systems with AI, Big Data, BlockChain, IoT, and Machine Learning Applications)
Abstract Aiming at the difficulty of rolling bearing fault diagnosis of wind turbine under noise environment, a new bearing fault identification method based on the Improved Anti-noise Residual Shrinkage Network (IADRSN) is proposed. Firstly, the vibration signals of wind turbine rolling bearings were preprocessed to obtain data samples divided into training and test sets. Then, a bearing fault diagnosis model based on the improved anti-noise residual shrinkage network was established. To improve the ability of fault feature extraction of the model, the convolution layer in the deep residual shrinkage network was replaced with a Dense-Net layer. To further improve the anti-noise… More
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Assessment Framework of Green Intelligent Transformation of Small Hydropower in China
Jun Shi^*
Energy Engineering, Vol.119, No.2, pp. 681-697, 2022, DOI:10.32604/ee.2022.014942
（This article belongs to this Special Issue: Energy Systems Management and Climate Change)
Abstract With the comprehensive promoted construction of the establishment of green small hydropower, the defects of existing small hydropower station are gradually emerging, and it is necessary to implement green intelligent transformation to promote the construction of energy internet in China. This study focuses on constructing a green intelligent planning and transforming assessment framework, and assists management department to filtrate the small hydropower stations which can be transformed reasonably. Firstly, power station economy, ecological environment, technical safety management and social benefits are involved in the assessment index system. Secondly, multi-expert judgment aggregation based on fuzzed comparison scale is put forward to… More
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Research on Phase-Shifted Full-Bridge Circuit Based on Frequency and Phase-Shift Synthesis Modulation Strategy
Mingda Jiang¹, Yanbo Che¹, Hongfeng Li^1,*, Muhammad Ishaq¹, Chao Xing^1,2
Energy Engineering, Vol.119, No.2, pp. 699-721, 2022, DOI:10.32604/ee.2022.017556
Abstract The full-bridge converters usually use transformer leakage inductance and parallel resonant capacitors to achieve smooth current commutation and soft switching functions, which can easily cause problems such as energy leakage and significant duty cycle loss. This paper designs a novel full-bridge zero-current (FB-ZCS) converter with series resonant capacitors and proposes a frequency and phase-shift synthesis modulation (FPSSM) control strategy based on this topology. Compared with the traditional parallel resonant capacitor circuit, the passive components used are significantly reduced, the structure is simple, and there is only a slight energy loss. By controlling the charging time of the capacitor, it can… More
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Dynamic Simulation and Performance Analysis on Multi-Energy Coupled CCHP System
Xueqin Tian¹, Jinfei Sun², Tong Xu¹, Mengran Cui², Xinlei Wang¹, Jianxiang Guo², De-gejirifu^1,*, Na Wang¹
Energy Engineering, Vol.119, No.2, pp. 723-737, 2022, DOI:10.32604/ee.2022.015982
Abstract Although the Combined Cooing, Heating and Power System (hereinafter referred to as “CCHP”) improves the capacity utilization rate and energy utilization efficiency, single use of CCHP system cannot realize dynamic matching between supply and demand loads due to the unbalance features of the user’s cooling and heating loads. On the basis of user convenience and wide applicability of clean air energy, this paper tries to put forward a coupled CCHP system with combustion gas turbine and ASHP ordered power by heat, analyze trends of such parameters as gas consumption and power consumption of heat pump in line with adjustment of… More
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Kalman Filter Estimation of Lithium Battery SOC Based on Model Capacity Updating
Min Deng¹, Quan Min¹, Ge Yang¹, Man Yu^2,3,*
Energy Engineering, Vol.119, No.2, pp. 739-754, 2022, DOI:10.32604/ee.2022.018025
（This article belongs to this Special Issue: Sustainable energy for transport)
Abstract High-precision estimation of lithium battery SOC can effectively optimize vehicle energy management, improve lithium battery safety protection, extend lithium battery cycle life, and reduce new energy vehicle costs. Based on the forgetting factor recursive least square method (FFRLS), Thevenin equivalent circuit model and Singular Value Decomposition-Unscented Kalman Filter (SVD-UKF), the SVD-UKF combined lithium battery SOC estimation algorithm with model capacity update is proposed, aiming at further improving the SOC estimation accuracy of lithium battery. The parameter identification of Thevenin model is studied by using the forgetting factor recursive least square method. To overcoming the shortcomings of Kalman filter linearization error… More
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Research on Power Consumption Anomaly Detection Based on Fuzzy Clustering and Trend Judgment
Wei Xiong^1,2, Xianshan Li^1,2,*, Yu Zou³, Shiwei Su^1,2, Li Zhi^1,2
Energy Engineering, Vol.119, No.2, pp. 755-765, 2022, DOI:10.32604/ee.2022.018009
Abstract Among the end-users of the power grid, especially in the rural power grid, there are a large number of users and the situation is complex. In this complex situation, there are more leakage caused by insulation damage and a small number of users stealing electricity. Maintenance staff will take a long time to determine the location of the abnormal user meter box. In view of this situation, the method of subjective fuzzy clustering and quartile difference is adopted to determine the partition threshold. The power consumption data of end-users are divided into three regions: high, normal and low, which can… More
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Model-Free Sliding Mode Control for PMSM Drive System Based on Ultra-Local Model
Kaihui Zhao^1,2, Wenchang Liu¹, Tonghuan Yin³, Ruirui Zhou⁴, Wangke Dai¹ and Gang Huang^5,*
Energy Engineering, Vol.119, No.2, pp. 767-780, 2022, DOI:10.32604/EE.2021.018617
Abstract This paper presents a novel model-free sliding mode control (MFSMC) method to improve the speed response of permanent magnet synchronous machine (PMSM) drive system. The ultra-local model (ULM) is first derived based on the input and the output of the PMSM. Then, the novel MFSMC method is presented, and the controller is designed based on ULM and MFSMC. A sliding mode observer (SMO) is constructed to estimate the unknown part of the ULM. The estimated unknown part is feedbacked to MFSMC controller to perform compensation for parameter perturbations and external disturbances. Compared with the sliding mode control (SMC) method, the… More
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A Value-at-Risk Based Approach for PMU Placement in Distribution Systems
Min Liu^*
Energy Engineering, Vol.119, No.2, pp. 781-800, 2022, DOI:10.32604/ee.2022.016657
Abstract With the application of phasor measurement units (PMU) in the distribution system, it is expected that the performance of the distribution system state estimation can be improved obviously with the PMU measurements into consideration. How to appropriately place the PMUs in the distribution is therefore become an important issue due to the economical consideration. According to the concept of efficient frontier, a value-at-risk based approach is proposed to make optimal placement of PMU taking account of the uncertainty of measure errors, statistical characteristics of the pseudo measurements, and reliability of the measurement instrument. The reasonability and feasibility of the proposed… More
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Performance Evaluation of Small-channel Pulsating Heat Pipe Based on Dimensional Analysis and ANN Model
Xuehui Wang¹, Edward Wright¹, Zeyu Liu¹, Neng Gao^2,*, Ying Li³
Energy Engineering, Vol.119, No.2, pp. 801-814, 2022, DOI:10.32604/ee.2022.018241
（This article belongs to this Special Issue: Micro-nano scale heat transfer enhancement technology)
Abstract The pulsating heat pipe is a very promising heat dissipation device to address the challenge of higher heat-flux electronic chips, as it is characterised by excellent heat transfer ability and flexibility for miniaturisation. To boost the application of PHP, reliable heat transfer performance evaluation models are especially important. In this paper, a heat transfer correlation was firstly proposed for closed PHP with various working fluids (water, ethanol, methanol, R123, acetone) based on collected experimental data. Dimensional analysis was used to group the parameters. It was shown that the average absolute deviation (AAD) and correlation coefficient (r) of the correlation were… More
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Effect of Thermal Conductivity of Tube-Wall on Blow-Off Limit of a Micro-Jet Methane Diffusion Flame
Bing Liu¹, Yikun Chen¹, Huachen Liu¹, Qiao Wu¹, Minghui Wang¹, Jianlong Wan^2,*
Energy Engineering, Vol.119, No.2, pp. 815-826, 2022, DOI:10.32604/ee.2022.017988
（This article belongs to this Special Issue: Advanced Materials and Technologies for Sustainable Energy)
Abstract The operating range of the flow rate or flow velocity for the micro-jet flame is quite wide, which can be used as the heat source. In order to optimize the micro-jet tube combustor in terms of the solid material, the present paper numerically investigates the impact of thermal conductivity (λ_s) on the operating limit of micro-jet flame. Unexpectedly, the non-monotonic blow-off limits with the increase of λ_s is found, and the corresponding generation mechanisms are analyzed in terms of the thermal coupling effect, flow field, and strain effect. At first, the lower preheating temperature of the fuel and larger heat… More
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Energy and Life Cycle Assessment of Zinc/Water Nanofluid Based Photovoltaic Thermal System
Junaid Khan, Rashid Ali, Muzammil Zubair, Syed Mohd Yahya^*
Energy Engineering, Vol.119, No.2, pp. 827-846, 2022, DOI:10.32604/ee.2022.016344
（This article belongs to this Special Issue: Advanced Materials and Technologies for Sustainable Energy)
Abstract Cooling the PV surface in a Photovoltaic Thermal system is a pivotal operational aspect to be taken into account to achieve optimized values of performance parameters in a Photovoltaic Thermal System. The experimental design used in this study facilitates the flow of varying concentrations of Zn-water nanofluid in serpentine copper tubing installed at the rear of the PV panel thereby preventing the PV surface temperature from increasing beyond the threshold value at which a decrease in electrical efficiency starts to occur. This fusion of solar thermal with PV devices leads to better electrical and thermal efficiency values resulting in decreased… More
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Experimental Study on Flow and Heat Transfer Characteristics of Nanofluids in a Triangular Tube at Different Rotation Angles
Cong Qi^1,2,*, Chengchao Wang^1,2, Jinghua Tang^1,2, Dongtai Han²
Energy Engineering, Vol.117, No.2, pp. 63-78, 2020, DOI:10.32604/EE.2020.010433
Abstract Because of the poor thermal performance of ordinary tubes, a triangular tube was used to replace the smooth channel in the heat transfer system, and nanofluids were used to take the place of ordinary fluids as the heat transfer medium. High stability nanofluids were prepared, and an experimental set on flow and heat exchange was established. Effects of triangular tube rotation angles (α = 0°, 30°, 60°) as well as mass fractions of nanofluids (ω = 0.1%, 0.3%, 0.5%) on heat exchange and flow performance were experimentally considered at Reynolds numbers (Re = 800–8000). It was shown that the triangular… More
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Performance and Cost Analysis of Energy Production from Offshore Wind Turbines
Haytham Ayoub, Ehab Hussein Bani-Hani^*
Energy Engineering, Vol.117, No.1, pp. 41-47, 2020, DOI:10.32604/EE.2020.010412
Abstract Offshore wind turbine is analyzed theoretically and experimentally for improving wind energy harvesting. The energy produced is calculated at different wind speeds. The wind speed curve is generated by measuring the wind speed on daily base for one year. Curves that show the power extraction for experimental study and from the theoretical calculations are generated. The energy production investigation is expanded over a period of 15 years after comparing the annual energy production in theory and practice. The study shows the cost of electricity over the same time period assuming different interest rates. Three time intervals are shown that are… More
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Experimental Study on Modal and Harmonic Analysis of Small Wind Turbine Blades Using NACA 63-415 Aerofoil Cross-Section
Ajay Veludurthi¹, Venkateshwarlu Bolleddu^2,*
Energy Engineering, Vol.117, No.2, pp. 49-61, 2020, DOI:10.32604/EE.2020.010666
Abstract This work focused on modal and harmonic analysis of small wind turbine blades taken from the NACA 63415 series. The sandwich structure type composite blade is fabricated from GFRP and epoxy with Uni-vinyl hard foams of different alignments as stiffeners. In this work, the modal and harmonic analysis of different varieties of blades like solid, hallow and rectangular alignment blades is carried out by the finite element method using ANSYS 18.1 software. From Finite Element Analysis, the natural frequencies, amplitudes and mode shapes are obtained. Based on the working principle of wind turbine blades, the boundary conditions are applied. The… More
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Research on the Measurement and Countermeasure of Coal Overcapacity in China: Based on Panel Data of 25 Provinces in China
Rijia Ding¹, Xingyao Zhou^1,*, Rui Zhang¹, Wanqiu Lu²
Energy Engineering, Vol.117, No.1, pp. 27-39, 2020, DOI:10.32604/EE.2020.010372
Abstract Coal is the main energy source in China. At present, the coal overcapacity is still serious in China. Accurately measuring the degree of China’s coal overcapacity can scientifically resolve the overcapacity, and is the premise of guiding the healthy development of coal industry and energy system. Using the translog cost function and the panel data of coal industry in all provinces of China from 2002 to 2011 and from 2012 to 2016, the research measures and compares the coal production capacity of “golden decade” and “cold winter” in China. The results show that: (1) The change of coal production capacity… More
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Energy Efficiency Effectiveness of Smart Thermostat Based BEMS
Koushik Mandlem, Bhaskaran Gopalakrishnan^*, Ashish Nimbarte, Roseline Mostafa, Rupa Das
Energy Engineering, Vol.117, No.4, pp. 165-183, 2020, DOI:10.32604/EE.2020.011406
Abstract The research details the design and development of a spreadsheet based software system that has been built using the principles of Monte Carlo simulation. The simulation has been applied to a residential building with a certain number of rooms, each with specific characteristics pertaining to volume, occupancy, and thermostat set point. The consideration of variables related to the building envelope and weather, and the HVAC system have provided a realistic view that enables the accurate estimation of annual energy usage and costs. The main findings of the research are reflected in the sensitivity analysis that estimates energy use and cost… More
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Unsteady Natural Convection within an Attic-Shaped Space Subject to Sinusoidal Heat Flux on Inclined Walls
Suvash C. Saha^1,*, Ali M. Sefidan², Atta Sojoudi³
Energy Engineering, Vol.117, No.1, pp. 1-17, 2020, DOI:10.32604/EE.2020.010418
Abstract Free convection inside an attic enclosure in which sinusoidal heat flux applied on the inclined walls and a constant temperature applied on the base wall has been investigated numerically to demonstrate the primary flow characteristics and heat transfer within the attic enclosure over daily routine cycles. To solve the governing equations, the finite volume technique has been utilized. After performing the grid independency and time step size tests, the roles of Rayleigh number (Ra) and the attic aspect ratio (AR) on the unsteady flow structure and heat transfer phenomenon are explained for a constant Prandtl number (0.72) for the air.… More
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