José María Esbrí^*, Alba Martinez-Coronado, Sofía Rivera Jurado, Eva García-Noguero, Pablo Higueras

Energy Engineering, Vol.118, No.4, pp. 1223-1235, 2021, DOI:10.32604/EE.2021.015781

Abstract Mercury (Hg) is a global pollutant that is subject to strict regulations to reduce anthropogenic emissions. The production of energy represents an important activity that leads to Hg emissions into the atmosphere. Of all the systems used, IGCC plants are the most promising for reducing Hg emissions, since it is possible to remove Hg from syngas prior to combustion. The aim of the present work was to evaluate the presence of Hg in the main streams of an experimental IGCC plant (ELCOGAS, Puertollano) in order to quantify Hg emissions and investigate the possibility of reducing them. The main streams of… More >

Dieudonné Kaoga Kidmo^1,*, Bachirou Bogno^1,2,3, Kodji Deli¹, Michel Aillerie^2,3

Energy Engineering, Vol.118, No.4, pp. 931-945, 2021, DOI:10.32604/EE.2021.015574

Abstract In the present work, an assessment of the rural water supply potential by mechanical wind pumping around the floodplains of Lake Chad has been considered. Inside the floodplains around Lake Chad, available surface water is largely contaminated and represents health hazards to populations. Access to underground and clean water has increasingly become rare. Moreover, clean water scarcity has led to conflict and territorial pressures, which are contributing factors to poverty in the considered area. Four localities, Baga, Baga-Sola, Makari and Nguigmi, respectively, in Nigeria, Chad, Cameroon and Niger have been selected inside the floodplains around Lake Chad, to evaluate the… More >

Ruichao Zhang^1,*, Liqiang Wang¹, Dechun Chen²

Energy Engineering, Vol.118, No.4, pp. 1069-1082, 2021, DOI:10.32604/EE.2021.014961

Abstract In recent years, deep learning models represented by convolutional neural networks have shown incomparable advantages in image recognition and have been widely used in various fields. In the diagnosis of sucker-rod pump working conditions, due to the lack of a large-scale dynamometer card data set, the advantages of a deep convolutional neural network are not well reflected, and its application is limited. Therefore, this paper proposes an intelligent diagnosis method of the working conditions in sucker-rod pump wells based on transfer learning, which is used to solve the problem of too few samples in a dynamometer card data set. Based… More >

Sakarias Paaso^*, Ali Khosravi

Energy Engineering, Vol.118, No.4, pp. 1111-1133, 2021, DOI:10.32604/EE.2021.014949

Abstract Potential revenue from wind power generation is an important factor to be considered when planning a wind power investment. In the future, that may become even more important because it is known that wind power generation tends to push electricity wholesale prices lower. Consequently, it is possible that if a region has plenty of installed wind power capacity, revenue per generated unit of electricity is lower there than could be assumed by looking at the mean electricity wholesale price. In this paper, we compare 17 different locations in Finland in terms of revenue from wind power generation. That is done… More >

Vin Cent Tai^1,*, Yong Chai Tan¹, Nor Faiza Abd Rahman¹, Yaw Yoong Sia², Chan Chin Wang², Lip Huat Saw³

Energy Engineering, Vol.118, No.4, pp. 1057-1068, 2021, DOI:10.32604/EE.2021.014866

Abstract Aircraft engine design is a complicated process, as it involves huge number of components. The design process begins with parametric cycle analysis. It is crucial to determine the optimum values of the cycle parameters that would give a robust design in the early phase of engine development, to shorten the design cycle for cost saving and man-hour reduction. To obtain a robust solution, optimisation program is often being executed more than once, especially in Reliability Based Design Optimisations (RBDO) with Monte-Carlo Simulation (MCS) scheme for complex systems which require thousands to millions of optimisation loops to be executed. This paper… More >

Cong Qi^*, Yuxing Wang, Zi Ding, Jianglin Tu, Mengxin Zhu

Energy Engineering, Vol.118, No.4, pp. 825-852, 2021, DOI:10.32604/EE.2021.014806

Abstract Boiling heat transfer is a mode using the phase change of working medium to strengthen the heat exchange due to its good heat exchange capability, and it is widely used in heat exchange engineering. Nanofluids have been used in the direction of enhanced heat transfer for their superior thermophysical property. The wetting, spreading and ripple phenomena of superhydrophobic surfaces widely exist in nature and daily life. It has great application value for engineering technology. In this article, the boiling heat exchange characteristics of nanofluids on superhydrophobic surface are numerically studied. It was found that with the increase of superheating degree,… More >

Yilin Hu¹, Yan Xie², Bo Li^3,*, Yiqiang Jiang¹, Fu Bao¹

Energy Engineering, Vol.118, No.4, pp. 911-929, 2021, DOI:10.32604/EE.2021.014759

Abstract Wind turbine employs pitch angle control to maintain captured power at its rated value when the wind speed is higher than rated value. This work adopts a perturbation observer based sliding-mode control (POSMC) strategy to realize robust variable-pitch control of permanent magnet synchronous generator (PMSG). POSMC combines system nonlinearities, parametric uncertainties, unmodelled dynamics, and time-varying external disturbances into a perturbation, which aims to estimate the perturbation via a perturbation observer without an accurate system model. Subsequently, sliding mode control (SMC) is designed to completely compensate perturbation estimation in real-time for the sake of achieving a global consistent control performance and… More >

Xiaojuan Lu, Zeping Liang^*

Energy Engineering, Vol.118, No.4, pp. 1171-1183, 2021, DOI:10.32604/EE.2021.014724

Abstract There are two prominent features in the process of temperature control in solar collector field. Firstly, the dynamic model of solar collector field is nonlinear and complex, which needs to be simplified. Secondly, there are a lot of random and uncontrollable, measurable and unmeasurable disturbances in solar collector field. This paper uses Taylor formula and difference approximation method to design a dynamic matrix predictive control (DMC) by linearizing and discretizing the dynamic model of the solar collector field. In addition, the purpose of controlling the stability of the outlet solar field salt temperature is achieved by adjusting the mass flow… More >

Wenhui Zhao¹, Yibo Yin^1,*, Lu Mao², Konglu Zhong³, Guanghui Yuan⁴, Hai Huang⁵, Yige Yang⁶

Energy Engineering, Vol.118, No.4, pp. 1009-1026, 2021, DOI:10.32604/EE.2021.014650

Abstract Changes in the energy price system will determine the direction of evolution of the energy industry structure. As a country where coal is the dominant energy source, what is the effect of coal price fluctuations on China’s industry development costs and energy consumption structure? To investigate this problem, this paper utilized an economy–energy–environment computable general equilibrium model. In this study, four aspects were analyzed: Energy supply side, proportion of renewable energy consumption, macroeconomy, and changes in CO₂ emissions. The results of this study show that an increase of 10%–20% in coal prices contributes to a shift into using renewable energy,… More >

Xinhong Xue¹, Zhongcheng Wang^2,*

Energy Engineering, Vol.118, No.4, pp. 995-1008, 2021, DOI:10.32604/EE.2021.014613

Abstract Electricity shortages present a significant constraint on manufacturers, who rely on electricity as an important input into production. In China, electricity supply has been growing rapidly. However, the rapid industrialization sometimes makes the power supply still unable to meet the demand. Using a survey of 1673 Chinese manufacturing firms, this paper explores how firms response to electricity shortages and its impact on productivity. We find that self-generation of electricity and investment in Research and Development (R&D) have significant positive relationships with electricity shortages. Further investigations reveal that self-generation is the most common way to deal with electricity shortages. However, it… More >