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 >

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 >

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 >

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

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 >

Zihao Wang, Dunxi Yu^*, Jingkun Han, Jianqun Wu

Energy Engineering, Vol.118, No.5, pp. 1267-1276, 2021, DOI:10.32604/EE.2021.016107

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 >

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

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 >

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 >

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 >

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 >

Bingbing Chen^*, Zhengyi Zhu, Xuyan Wang, Can Zhang

Energy Engineering, Vol.118, No.5, pp. 1499-1514, 2021, DOI:10.32604/EE.2021.015145

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 >