Ting Chen¹, Oh Kyung Kwon^2,*

Energy Engineering, Vol.119, No.6, pp. 2231-2242, 2022, DOI:10.32604/ee.2022.021289

Abstract With the limited production and use of R245fa, environmentally friendly refrigerant has attracted the attention of researchers. Due to the similar thermal characteristics, R1233zd(E) is considered to be an ideal substitute for R245fa in heat pump systems. In this study, the performance and economic analysis of heat pump systems with R245fa and R1233zd(E) as refrigerants are carried out. The results show that the total cost of R1233zd(E) system is more than 10% higher than that of R245fa system under the same heating load. With the increase of condensation temperature, the heating capacity of both systems decreases, and with the increase… More >

Bing Wang^1,2,*, Zhongxun Li¹, Rui Shi¹, Yuzheng Zhang¹, Yao Yao¹

Energy Engineering, Vol.119, No.6, pp. 2469-2487, 2022, DOI:10.32604/ee.2022.021171

Abstract With policy incentives for the coalbed methane in energy industry, coalbed methane from coal production has been effectively improved by technology innovations in coalbed methane extraction and utilization. The progress of coalbed methane promotes the clean construction of energy system and contributes to carbon neutrality target. To quantitatively measure the contributions of the coalbed methane in energy industry, this paper builds a carbon emissions accounting system for coalbed methane in China and assesses the historical co-benefits of coalbed methane utilization from the aspects of emissions reduction, safety and economy. By using the parameters of gas content, raw coal production, gas… More >

Yangsheng Sun¹, Zhihua Wang¹, Gaoqin Wang², Beibei Wang^3,*

Energy Engineering, Vol.119, No.6, pp. 2193-2210, 2022, DOI:10.32604/ee.2022.020943

Abstract The market power mitigation method of the supply-side has become one of the key points affecting the stability of the electricity spot market. Different mitigation mechanisms are used in the current mature electricity markets of the world. However, the same market power mitigation mechanism shows different effects in different market environments. Every market operator in the world needs the most efficient way to mitigate market power. Considering that there is no relevant literature discussing the market power effects of different mitigation methods in detail, the mitigation effects need to be discussed and further researched. So, we analyze the effects of… More >

Rao Fu^1,*, Liming Wang², Xuesong Huo², Pei Pei², Haitao Jiang³, Zhongxing Fu⁴

Energy Engineering, Vol.119, No.6, pp. 2621-2636, 2022, DOI:10.32604/ee.2022.020873

Abstract The power infrastructure of the power system is massive in size and dispersed throughout the system. Therefore, how to protect the information security in the operation and maintenance of power equipment is a difficult problem. This paper proposes an improved time-stamped blockchain technology biometric fuzzy feature for electrical equipment maintenance. Compared with previous blockchain transactions, the time-stamped fuzzy biometric signature proposed in this paper overcomes the difficulty that the key is easy to be stolen by hackers and can protect the security of information during operation and maintenance. Finally, the effectiveness of the proposed method is verified by experiments. More >

Yuxia Han^1,2, Jianwen Wang^1,2,*, Xin Li³, Xueqing Dong^1,2, Caifeng Wen^1,2

Energy Engineering, Vol.119, No.6, pp. 2297-2317, 2022, DOI:10.32604/ee.2022.020858

Abstract The evolution laws of the large-eddy coherent structure of the wind turbine wake have been evaluated via wind tunnel experiments under uniform and turbulent inflow conditions. The spatial correlation coefficients, the turbulence integral scales and power spectrum are obtained at different tip speed ratios (TSRs) based on the time-resolved particle image velocity (TR-PIV) technique. The results indicate that the large-eddy coherent structures are more likely to dissipate with an increase in turbulence intensity and TSR. Furthermore, the spatial correlation of the longitudinal pulsation velocity is greater than its axial counterpart, resulting into a wake turbulence dominated by the longitudinal pulsation.… More >

Xiyang Li¹, Yuhao Jia², Hui Zhang^1,*, Bin Cheng¹

Energy Engineering, Vol.119, No.6, pp. 2549-2567, 2022, DOI:10.32604/ee.2022.020854

Abstract Icing can significantly change the geometric parameters of wind turbine blades, which in turn, can reduce the aerodynamic characteristics of the airfoil. In-depth research is conducted in this study to identify the reasons for the decline of wind power equipment performance through the icing process. An accurate experimental test method is proposed in a natural environment that examines the growth and distribution of ice formation over the airfoil profile. The mathematical models of the airfoil chord length, camber, and thickness are established in order to investigate the variation of geometric airfoil parameters under different icing states. The results show that… More >

Ruoqiong Li^1,*, Linrun Xiao¹, Jingtao Lu², Xin Li²

Energy Engineering, Vol.119, No.6, pp. 2533-2548, 2022, DOI:10.32604/ee.2022.020803

Abstract In electrified railways, traction load not only fluctuates between peaks and valleys, but also has a situation of low utilization rate of average load throughout the day and short overload. The traction transformer selects the capacity with the peak load as the demand boundary, which will cause the capacity utilization rate to be low and even lead to the economic decline of the traction power supply system. This article summarizes the existing configuration methods for capacity optimization of traction transformer. Then under the conditions of energy storage and new energy access to traction power supply system, the three aspects are… More >

Jiageng Zhang¹, Zhengfeng Wang², Jiguang Huang¹, Chao Cheng¹, Heng Zhang¹, Dan Gao^1,*

Energy Engineering, Vol.119, No.6, pp. 2277-2296, 2022, DOI:10.32604/ee.2022.020795

Abstract

Nowadays, the zero liquid discharge of flue gas desulfurization (FGD) wastewater from coal-fired units has attracted the attention of all countries in the world. The pretreatment methods generally have the problems of high operation cost, small treatment capacity, and poor flexibility. However, the membrane method can avoid the above problems. In the current research, it has not been found that someone directly uses submerged ultrafiltration to pretreat FGD wastewater. Therefore, this paper innovatively proposed to directly use ceramic ultrafiltration membrane to treat FGD wastewater, which can ensure effluent quality and improve the flexibility of the pretreatment system. In this paper,… More >

Sihua Wang^1,2, Wenhui Zhang^1,2,*, Gaofei Zheng^1,2, Xujie Li^1,2, Yougeng Zhao^1,2

Energy Engineering, Vol.119, No.6, pp. 2431-2445, 2022, DOI:10.32604/ee.2022.020779

Abstract In order to improve the condition monitoring and fault diagnosis of wind turbines, a stacked noise reduction autoencoding network based on group normalization is proposed in this paper. The network is based on SCADA data of wind turbine operation, firstly, the group normalization (GN) algorithm is added to solve the problems of stack noise reduction autoencoding network training and slow convergence speed, and the RMSProp algorithm is used to update the weight and the bias of the autoenccoder, which further optimizes the problem that the loss function swings too much during the update process. Finally, in the last layer of… More >

Zhao Wang¹, Su Yan¹, Mingfeng Zhu¹, Wen Zhu¹, Han Zhang², Xiang Gou^2,*

Energy Engineering, Vol.119, No.6, pp. 2569-2584, 2022, DOI:10.32604/ee.2022.020644

Abstract Aiming at improving the performance of Organic Rankine Cycle (ORC) system with low-grade steam as heat source, this work studied and optimized the main operating parameters of the ORC system. The effects of evaporation temperature, superheat degree, condensation temperature and regenerator pinch temperature difference on the system performance were obtained. The optimization for the operating parameters is based on the indicators of specific net power output, waste heat pollution, cycle exergy efficiency, and total UA value (the product of overall heat transfer coefficient and heat transfer area of heat exchanger). The results show that the increase of the evaporation temperature… More >