Home / Journals / ENERGY / Vol.118, No.3, 2021
  • Open Access

    REVIEW

    Industrial and Small-Scale Biomass Dryers: An Overview

    P. Murugan1, S. Dhanushkodi2,*, K. Sudhakar3,4,*, Vincent H. Wilson5
    Energy Engineering, Vol.118, No.3, pp. 435-446, 2021, DOI:10.32604/EE.2021.013491
    Abstract The quality of the drying process depends mainly on the efficient use of thermal energy. Sustainable systems based on solar energy takes a leading role in the drying of agro-products because of low operating cost. However, they are limited in use during off–sun periods. Biomass dryer is one of the simplest ways of drying because of its potential to dry products regardless of time and climate conditions. The other benefit is that crop residues could be used as fuel in these systems. However, the major limitation of the dryer is unequal drying because of poor airflow distribution in the drying… More >

  • Open Access

    ARTICLE

    Energy and Cost Analysis of Processing Flat Plate Solar Collectors

    Mamdouh El Haj Assad1,*, Ali Khosravi2, Mohammad AlShabi3, Bassam Khuwaileh3, Abdul-Kadir Hamid4
    Energy Engineering, Vol.118, No.3, pp. 447-458, 2021, DOI:10.32604/EE.2021.014590
    Abstract In this work, a life cycle analysis is accomplished for flat plate solar collectors. The purpose of this investigation is to predict the energy consumption during the manufacturing processes that results in carbon dioxide emissions. Energy consumption and system efficiency enhancement will be studied and predicted. CES EduPack software is used to perform the analysis of the currently commercial system, and the suggested changes are implemented to increase the efficiency and make the comparison. Even though cost analysis is done, the priority of selection is given to the most energy conserving and environmentally friendly alternative. However, if the compared alternatives… More >

  • Open Access

    ARTICLE

    Scavenging Effects of Kaolin on Fine Ash Formation during Zhundong Coal Combustion

    Fangqi Liu1, Xianpeng Zeng1,2, Yimin Xia1, Zihao Wang1, Dunxi Yu1,*
    Energy Engineering, Vol.118, No.3, pp. 459-471, 2021, DOI:10.32604/EE.2021.014240
    (This article belongs to this Special Issue: Advancement of Understanding of PM2.5 and Hg Emissions and Their Control Technologies for Cleaner Combustion)
    Abstract The previous work found that the additive kaolin could scavenge not only sodium (Na) but also calcium (Ca) and magnesium (Mg), which is the important ash fluxing agents in low rank coal combustion. Such scavenging effects of kaolin on fine ash formation were studied in the present work. A typical Zhundong coal and its blends with kaolin at dosages of 1, 2 and 4 wt% were combusted in an electrically heated drop tube furnace (DTF) at 1300°C. The fine ashes generated were collected and size segregated by a low pressure impactor (LPI). The morphology and chemical composition of fine ash… More >

  • Open Access

    ARTICLE

    Emission Behaviors of Submicron Particles (PM1) Generated by the Combustion of Sesame Stalk after Combined Water Washing and Carbonization Pretreatment

    Tianyu Liu1, Chang Wen1,2,3,*, Wenyu Wang1, Kai Yan3, Yongjun Xia4, Rui Li3, Juan Liu4, Yang Zhang1
    Energy Engineering, Vol.118, No.3, pp. 473-485, 2021, DOI:10.32604/EE.2021.014870
    (This article belongs to this Special Issue: Advancement of Understanding of PM2.5 and Hg Emissions and Their Control Technologies for Cleaner Combustion)
    Abstract Pretreatment before biomass combustion is significant for its efficient utilization and that combined water washing and carbonization can be efficient. An agricultural processing residues sesame stalk was selected and carried out two pretreatments separately, i.e., water washing-torrefaction (W-T) and torrefaction-water washing (T-W), to explore the effect on the fuel properties, combustion characteristics and particulate matter (PM) emission. The obtained biochar was also combusted under air and oxy50 (CO2:O2 = 50:50) conditions for the sake of investigating the effect of pretreatment and combustion atmosphere. The results indicate that, W-T and T-W both not only have great effect on the improvement of… More >

  • Open Access

    ARTICLE

    Transient Free Convection and Heat Transfer in a Partitioned Attic-Shaped Space under Diurnal Thermal Forcing

    Suvash C. Saha1,*, Ali M. Sefidan2, Atta Sojoudi3, Mohammad M. Molla4
    Energy Engineering, Vol.118, No.3, pp. 487-506, 2021, DOI:10.32604/EE.2021.014088
    Abstract One primordial consideration in residential ventilation standards is the comfort of provided to people living in those habitations. This is highly dependent on the thermal and fluid flow conditions, the space geometry and so on. Efficient designs may reduce the energy usage, making the buildings more sustainable over a longer period of time. This study aims to investigate the impact of whole day thermal conditions on the fluid flow structure and heat transfer phenomena, mainly natural convection, inside a partitioned attic-shaped configuration. The Finite Volume Method is applied to solve the governing equations. Sinusoidal thermal boundary condition is applied on… More >

  • Open Access

    ARTICLE

    A Novel Power Curve Prediction Method for Horizontal-Axis Wind Turbines Using Artificial Neural Networks

    Vin Cent Tai1,*, Yong Chai Tan1, Nor Faiza Abd Rahman1, Chee Ming Chia2, Mirzhakyp Zhakiya2, Lip Huat Saw3
    Energy Engineering, Vol.118, No.3, pp. 507-516, 2021, DOI:10.32604/EE.2021.014868
    (This article belongs to this Special Issue: The Role of Artificial Intelligence for Modeling and Optimizing the Energy Systems )
    Abstract Accurate prediction of wind turbine power curve is essential for wind farm planning as it influences the expected power production. Existing methods require detailed wind turbine geometry for performance evaluation, which most of the time unattainable and impractical in early stage of wind farm planning. While significant amount of work has been done on fitting of wind turbine power curve using parametric and non-parametric models, little to no attention has been paid for power curve modelling that relates the wind turbine design information. This paper presents a novel method that employs artificial neural network to learn the underlying relationships between… More >

  • Open Access

    ARTICLE

    Performance Characteristics of Geothermal Single Well for Building Heating

    Jingying Li1, Tiejun Zhu1, Fengming Li1, Dong Wang1, Xianbiao Bu2, Lingbao Wang2,*
    Energy Engineering, Vol.118, No.3, pp. 517-534, 2021, DOI:10.32604/EE.2021.014464
    (This article belongs to this Special Issue: Advanced Heat Pump Technologies for Renewable Energy Utilization)
    Abstract The single well geothermal heating (SWGH) technology has attracted extensive attention. To enhance heat extraction from SWGH, a mathematical model describing heat transfer is set up, and the key influence factor and heat transfer enhancement method are discussed by thermal resistance analysis. The numerical results show that the thermal resistance of rock is far greater than that of well wall and fluid. So, reducing rock thermal resistance is the most effective method for enhancing the heat extraction power. For geothermal well planning to drill: rock thermal resistance can be reduced by increasing well diameter and rock thermal conductivity; the temperature… More >

  • Open Access

    ARTICLE

    Research on Operation of Electrothermal Integrated Energy System Including Heat Pump and Thermal Storage Units Based on Capacity Planning

    Taihong Liu1, Dingchen Wu2,*, Fei Xu3, Panpan Song2, Mingshan Wei2, Jian Wu1, Xiaochun Bai1
    Energy Engineering, Vol.118, No.3, pp. 535-548, 2021, DOI:10.32604/EE.2021.014326
    Abstract In view of the Three North areas existing wind power absorption and environment pollution problems, the previous scholars have improved the wind abandon problem by adding electrothermal coupling equipment or optimizing power grid operation. In this paper, an electrothermal integrated energy system including heat pump and thermal storage units was proposed. The scheduling model was based on the load data and the output characteristics of power units, each power unit capacity was programmed without constraints, and the proposed scheduling model was compared with the traditional combined heat and power scheduling model. Results showed that the investment and pollutant discharge of… More >

  • Open Access

    ARTICLE

    Power Data Preprocessing Method of Mountain Wind Farm Based on POT-DBSCAN

    Anfeng Zhu, Zhao Xiao, Qiancheng Zhao*
    Energy Engineering, Vol.118, No.3, pp. 549-563, 2021, DOI:10.32604/EE.2021.014177
    (This article belongs to this Special Issue: Wind Energy Development and Utilization)
    Abstract Due to the frequent changes of wind speed and wind direction, the accuracy of wind turbine (WT) power prediction using traditional data preprocessing method is low. This paper proposes a data preprocessing method which combines POT with DBSCAN (POT-DBSCAN) to improve the prediction efficiency of wind power prediction model. Firstly, according to the data of WT in the normal operation condition, the power prediction model of WT is established based on the Particle Swarm Optimization (PSO) Arithmetic which is combined with the BP Neural Network (PSO-BP). Secondly, the wind-power data obtained from the supervisory control and data acquisition (SCADA) system… More >

  • Open Access

    ARTICLE

    Probabilistic Load Flow Calculation of Power System Integrated with Wind Farm Based on Kriging Model

    Lu Li1, Yuzhen Fan2, Xinglang Su1,*, Gefei Qiu1
    Energy Engineering, Vol.118, No.3, pp. 565-580, 2021, DOI:10.32604/EE.2021.014627
    (This article belongs to this Special Issue: Wind Energy Development and Utilization)
    Abstract Because of the randomness and uncertainty, integration of large-scale wind farms in a power system will exert significant influences on the distribution of power flow. This paper uses polynomial normal transformation method to deal with non-normal random variable correlation, and solves probabilistic load flow based on Kriging method. This method is a kind of smallest unbiased variance estimation method which estimates unknown information via employing a point within the confidence scope of weighted linear combination. Compared with traditional approaches which need a greater number of calculation times, long simulation time, and large memory space, Kriging method can rapidly estimate node… More >

  • Open Access

    ARTICLE

    Optimization of Combustion Characteristics and Fuel Injection Timing of a New Type Dual-Pit Combustor Rotary Engine

    Zhongjia Li1, Jianfeng Pan1,*, Hongjun Liu1, Baowei Fan1, Wenming Yang2, Abiodun Oluwaleke Ojo1
    Energy Engineering, Vol.118, No.3, pp. 581-603, 2021, DOI:10.32604/EE.2021.014378
    Abstract In order to improve the performance of the rotary engine, this paper has designed a new type of dual-pit rotary engine combustion chamber structure, and compares the combustion and emission characteristics with the rotary engine with a traditional combustion chamber. The existence of the dual-pit combustion chamber strengthens the overall vortex intensity in the cylinder, effectively promotes the mixing process of fuel and air in the cylinder, the maximum combustion pressure in the cylinder increased by 8.6%, significantly increases the diffusion combustion speed, and significantly improves the dynamic performance of the rotary engine. On this basis, the effects of fuel… More >

  • Open Access

    ARTICLE

    Research on Reliability of Desorption Indexes of Drilling Cuttings (K1 and ∆h2): A Case-Based on Pingdingshan Mining Region, China

    Jianguo Zhang1, Biao Hu2,*, Xiyuan Li1, Hongxing Zhou2, Zhixu Dai3, Yanlei Lu3, Deyang Wang2
    Energy Engineering, Vol.118, No.3, pp. 605-614, 2021, DOI:10.32604/EE.2021.014655
    Abstract To accurately predict the risk of coal and gas outburst and evaluate the reliability of desorption indexes of drilling cuttings (K1 and ∆h2) in No. 16 coal seam of Pingmei No. 12 coal mine, two sets of coal samples were selected from the target coal seams for proximate analyses, methane adsorption/desorption tests, and desorption indexes of drilling cuttings tests. The results indicated that the desorption volume in the initial stage of desorption is large, and increases slowly in the later stage. The methane desorption volume of PMD1 and PMD2 coal samples accounts for 15.14%–18.09% and 15.72%–18.17% respectively in the first… More >

  • Open Access

    ARTICLE

    Qualitative Comparison between the Brazilian Labeling Program for Buildings and the Portuguese Energy Certification System for Buildings: Proposals for Improving Brazilian Regulations

    Jaime Francisco de Sousa Resende1,*, Andrea Lucia Teixeira Charbel2, Teresa Cristina Bessa Nogueira Assunção3
    Energy Engineering, Vol.118, No.3, pp. 615-629, 2021, DOI:10.32604/EE.2021.014588
    Abstract Buildings represent a significant share of the world’s energy consumption, and the sector has drawn the attention of governments, which have adopted policies to reduce energy expenditure. The Certifications of Energy Efficiency in Buildings stand out as one possible solution to achieve this goal, employed in several countries worldwide. The European Union presents advanced energy assessment programs for buildings, being a reference and model for several other regulations in the world. The Energy Certification System for Buildings (SCE) of Portugal is considered a success case, reflected in the significant number of energy certificates issued. The Brazilian Labeling Program for Building… More >

  • Open Access

    ARTICLE

    Simulation of Electric Field Distribution along Insulator Surface in Polluted Environments

    Yukun Lv, Yuechi Wang*, Jiawen Wang, Jing Wang, Jiaxi Yang
    Energy Engineering, Vol.118, No.3, pp. 631-642, 2021, DOI:10.32604/EE.2021.014578
    Abstract In recent years, more than 50% of the cities in the inland area of our country have suffered from moderate pollution. It can affect the distribution of electric field along the surface of insulator and the pollution characteristics of its surface area, even endanger the safe operation of transmission lines. This paper takes the XSP-160 porcelain three umbrella insulator under the action of 0–±30 kV DC voltage as the research object, and establishes the physical model of the insulator; uses COMSOL software to simulate the electric field of the insulator. The comparison with the results of the wind tunnel test… More >

  • Open Access

    ARTICLE

    Research on 48 V Super Capacitor Micro Hybrid System with 12 V Power Supply Multiplexing Function

    Wei Shi1, Shusheng Xiong1,*, Wei Li2, Bohao Zhang3
    Energy Engineering, Vol.118, No.3, pp. 643-654, 2021, DOI:10.32604/EE.2021.014643
    Abstract 48 V lithium battery micro hybrid system is the most fuel economy vehicle which can be mass produced at present. However, with the irreversible internal resistance increase of the key component 48 V lithium battery, and the capacity continues to decline, the system performance deteriorate. Worst case could be the system not functional in the middle and later age of vehicle life cycle. This paper studies the feasibility of using 48 V super capacitor as the replacement to 48 V lithium battery, and uses a 12 V module of 48 V super capacitor as the traditional 12 V power supply,… More >

  • Open Access

    ARTICLE

    The Non-Linear Effect of China’s Energy Consumption on Eco-Environment Pollution

    Chunhua Jin, Hanqing Hu*
    Energy Engineering, Vol.118, No.3, pp. 655-665, 2021, DOI:10.32604/EE.2021.014281
    Abstract With the increase of total energy consumption, eco-environmental quality drops sharply, which has attracted concerns from all circles. It has become the top priority of construction of socialist ecological civilization to clarify the influences of energy consumption on the level of eco-environmental pollution. Ecological environmental pollution control cannot be one size fits all. It can avoid resource depletion and environmental deterioration via adjusting measures to local conditions to coordinate ecological environmental pollution and energy consumption problems. In this essay, entropy method is adopted to measure the composite indexes of eco-environmental pollution of 30 provinces and cities in China, based on… More >

  • Open Access

    ARTICLE

    Design and Analysis of a Small Sewage Source Heat Pump Triple Supply System

    Chunxue Gao1,*, Yu Hao1, Qiuxin Liu1,2
    Energy Engineering, Vol.118, No.3, pp. 667-678, 2021, DOI:10.32604/EE.2021.014703
    Abstract Based on the characteristics of sewage from beauty salons, a simulation model of a small sewage source heat pump triple supply system that can be applied to such places is established to optimize the operating conditions of the system. The results show that with the increase of sewage temperature and flow, the performance of the system also increases. In summer conditions, the system provides cooling, recovers waste heat and condensed heat from sewage, with a COP value of 8.97; in winter conditions, the system heats and produces hot water, with a COP value of 2.44; in transitional seasons, only hot… More >

  • Open Access

    ARTICLE

    Prediction Model for Gas Outburst Intensity of Coal Mining Face Based on Improved PSO and LSSVM

    Haibo Liu1,*, Yujie Dong2, Fuzhong Wang1
    Energy Engineering, Vol.118, No.3, pp. 679-689, 2021, DOI: 10.32604/EE.2021.014630
    Abstract For the problems of nonlinearity, uncertainty and low prediction accuracy in the gas outburst prediction of coal mining face, the least squares support vector machine (LSSVM) is proposed to establish the prediction model. Firstly, considering the inertia coefficients as global parameters lacks the ability to improve the solution for the traditional particle swarm optimization (PSO), an improved PSO (IPSO) algorithm is introduced to adjust different inertia weights in updating the particle swarm and solve the fitness to stagnate. Secondly, the penalty factor and kernel function parameter of LSSVM are searched automatically, and the regression accuracy and generalization performance is enhanced… More >

  • Open Access

    ARTICLE

    Cloud Based Monitoring and Diagnosis of Gas Turbine Generator Based on Unsupervised Learning

    Xian Ma1, Tingyan Lv2,*, Yingqiang Jin2, Rongmin Chen2, Dengxian Dong2, Yingtao Jia2
    Energy Engineering, Vol.118, No.3, pp. 691-705, 2021, DOI:10.32604/EE.2021.012701
    Abstract The large number of gas turbines in large power companies is difficult to manage. A large amount of the data from the generating units is not mined and utilized for fault analysis. This study focuses on F-class (9F.05) gas turbine generators and uses unsupervised learning and cloud computing technologies to analyse the faults for the gas turbines. Remote monitoring of the operational status are conducted. The study proposes a cloud computing service architecture for large gas turbine objects, which uses unsupervised learning models to monitor the operational state of the gas turbine. Faults such as chamber seal failure, load abnormality… More >

  • Open Access

    ARTICLE

    Optimum Calculation of Coal Pillars in Inclined Weathered Oxidation Zone

    Yingbo Zhang1, Shi Chen1,2,*
    Energy Engineering, Vol.118, No.3, pp. 707-714, 2021, DOI:10.32604/EE.2021.013888
    Abstract In the mining process of coal mine, waterproof coal pillars should be set between the weathered oxidation zone and the first mining face. In order to determine the reasonable upper limit of the first mining face of Hongyi Coal Mine, the waterproof coal pillar needs to be wide enough to resist the lateral hydrostatic pressure of the oxidation zone, and to ensure that the top plate aquifer does not run through the water guide crack zone, while also liberating as much stagnant coal as possible. In this paper, the first coal mine face’s waterproof coal pillar was calculated using conventional… More >

  • Open Access

    ARTICLE

    Long-Term Electricity Demand Forecasting for Malaysia Using Artificial Neural Networks in the Presence of Input and Model Uncertainties

    Vin Cent Tai1,*, Yong Chai Tan1, Nor Faiza Abd Rahman1, Hui Xin Che2, Chee Ming Chia2, Lip Huat Saw3, Mohd Fozi Ali4
    Energy Engineering, Vol.118, No.3, pp. 715-725, 2021, DOI:10.32604/EE.2021.014865
    (This article belongs to this Special Issue: The Role of Artificial Intelligence for Modeling and Optimizing the Energy Systems )
    Abstract Electricity demand is also known as load in electric power system. This article presents a Long-Term Load Forecasting (LTLF) approach for Malaysia. An Artificial Neural Network (ANN) of 5-layer Multi-Layered Perceptron (MLP) structure has been designed and tested for this purpose. Uncertainties of input variables and ANN model were introduced to obtain the prediction for years 2022 to 2030. Pearson correlation was used to examine the input variables for model construction. The analysis indicates that Primary Energy Supply (PES), population, Gross Domestic Product (GDP) and temperature are strongly correlated. The forecast results by the proposed method (henceforth referred to as… More >

  • Open Access

    ARTICLE

    Evaluation of Environmental Quality for Abandoned Coal Mine Based on Environmental Vulnerability Index

    Peng Qi1,*, Yu Shang2,*
    Energy Engineering, Vol.118, No.3, pp. 727-736, 2021, DOI:10.32604/EE.2021.014203
    Abstract With the increasingly prominent environmental problems of abandoned coal mines, this paper discussed the significance of environmental vulnerability assessment of abandoned coal mines. Environmental vulnerability assessment is essentially an assessment of environmental quality. At present, the research object of environmental impact assessment method and program of mine is mostly single factor. However, the impact of abandoned coal mine on the environment is multifaceted, which was summarized into nine prominent common problems. Based on these nine factors, the environmental vulnerability assessment model of abandoned coal mine based on multifactor evaluation was established by using the analytic hierarchy process (AHP) method, the… More >

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