Tianyu Zhou¹, Liang Hao¹, Xin Xu^2,3, Meng Si^2,3, Lian Zhang^2,3,*

Energy Engineering, Vol.121, No.1, pp. 145-168, 2024, DOI:10.32604/ee.2023.042798

Abstract This paper discussed the experimental results of the performance of an organic Rankine cycle (ORC) system with an ultra-low temperature heat source. The low boiling point working medium R134a was adopted in the system. The simulated heat source temperature (SHST) in this work was set from 39.51°C to 48.60°C by the simulated heat source module. The influence of load percentage of simulated heat source (LPSHS) between 50% and 70%, the rotary valve opening (RVO) between 20% and 100%, the resistive load between 36 Ω and 180 Ω or the no-load of the generator, as well as the autumn and winter… More >

Caixia Tao, Shize Yang^*, Taiguo Li

Energy Engineering, Vol.121, No.1, pp. 187-201, 2024, DOI:10.32604/ee.2023.042421

Abstract With the current integration of distributed energy resources into the grid, the structure of distribution networks is becoming more complex. This complexity significantly expands the solution space in the optimization process for network reconstruction using intelligent algorithms. Consequently, traditional intelligent algorithms frequently encounter insufficient search accuracy and become trapped in local optima. To tackle this issue, a more advanced particle swarm optimization algorithm is proposed. To address the varying emphases at different stages of the optimization process, a dynamic strategy is implemented to regulate the social and self-learning factors. The Metropolis criterion is introduced into the simulated annealing algorithm to… More >

Wen Sun¹, Meijing Li², Guoxiang Li¹, Ke Sun^1,*, Shuzhan Bai^1,*

Energy Engineering, Vol.121, No.1, pp. 95-110, 2024, DOI:10.32604/ee.2023.042096

Abstract Proton exchange membrane fuel cells are widely regarded as having the potential to replace internal combustion engines in vehicles. Since fuel cells cannot recover energy and have a slow dynamic response, they need to be used with different power sources. Developing efficient energy management strategies to achieve excellent fuel economy is the goal of research. This paper proposes an adaptive equivalent fuel minimum consumption strategy (AECMS) to solve the problem of the poor economy of the whole vehicle caused by the wrong selection of equivalent factors (EF) in traditional ECMS. In this method, the kinematics interval is used to update… More >

Yanbo Shen^1,2, Yang Gao³, Yueming Hu^1,2, Xin Yao⁴, Wenzheng Yu^4,*, Yubing Zhang⁴

Energy Engineering, Vol.121, No.1, pp. 43-57, 2024, DOI:10.32604/ee.2023.041921

Abstract The Tibet Plateau is one of the regions with the richest solar energy resources in the world. In the process of achieving carbon neutrality in China, the development and utilization of solar energy resources in the region will play an important role. In this study, the gridded solar resource data with 1 km resolution in Tibet were obtained by spatial correction and downscaling of SMARTS model. On this basis, the spatial and temporal distribution characteristics of solar energy resources in the region in the past 30 years (1991–2020) are finely evaluated, and the annual global horizontal radiation resource is calculated.… More >

Shuangshuang Zhang^1,*, Kangliang Guo¹, Xinchen Gao¹, Haoran Yang¹, Jinfeng Zhang², Xing Han³

Energy Engineering, Vol.121, No.1, pp. 59-75, 2024, DOI:10.32604/ee.2023.041709

Abstract To improve the productivity of oil wells, perforation technology is usually used to improve the productivity of horizontal wells in oilfield exploitation. After the perforation operation, the perforation channel around the wellbore will form a near-well high-permeability reservoir area with the penetration depth as the radius, that is, the formation has different permeability characteristics with the perforation depth as the dividing line. Generally, the permeability is measured by the permeability tester, but this approach has a high workload and limited application. In this paper, according to the reservoir characteristics of perforated horizontal wells, the reservoir is divided into two areas:… More >

Hao Zhang¹, Yan Zhang^1,*, Wei Liu², Ximin Zhang³, Xiang Liu²

Energy Engineering, Vol.121, No.1, pp. 27-42, 2024, DOI:10.32604/ee.2023.041410

Abstract The microscopic characteristics and mechanical properties of rocks change after the action of acid on deep shale, which affects the fracturing effect. Accordingly, we designed and conducted indoor experiments related to the changes in macro and microscopic characteristics after the interaction of acid with the shale of Wujiaping Formation, based on which the characteristic law of fracture volume modification after acid fracturing was studied using numerical simulation. The results demonstrate that the pores and fractures are enlarged and the structure is significantly loosened after the acid immersion. And a 15% concentration of hydrochloric acid can effectively dissolve shale. Furthermore, the… More >

Qin Yao, Yida Zeng^*, Qingui Jia

Energy Engineering, Vol.121, No.1, pp. 221-241, 2024, DOI:10.32604/ee.2023.041028

Abstract In recent years, switched inductor (SL) technology, switched capacitor (SC) technology, and switched inductor-capacitor (SL-SC) technology have been widely applied to optimize and improve DC-DC boost converters, which can effectively enhance voltage gain and reduce device stress. To address the issue of low output voltage in current renewable energy power generation systems, this study proposes a novel non-isolated cubic high-gain DC-DC converter based on the traditional quadratic DC-DC boost converter by incorporating a SC and a SL-SC unit. Firstly, the proposed converter’s details are elaborated, including its topology structure, operating mode, voltage gain, device stress, and power loss. Subsequently, a… More >

Huaiyin He¹, Longqing Zou¹, Yanchao Li¹, Yixuan Wang¹, Junxiang Li¹, Huan Wen¹, Bei Chang¹, Lijun Liu^2,*

Energy Engineering, Vol.121, No.1, pp. 111-123, 2024, DOI:10.32604/ee.2023.041010

Abstract Multistage multi-cluster hydraulic fracturing has enabled the economic exploitation of shale reservoirs, but the interpretation of hydraulic fracture parameters is challenging. The pressure signals after pump shutdown are influenced by hydraulic fractures, which can reflect the geometric features of hydraulic fracture. The shutdown pressure can be used to interpret the hydraulic fracture parameters in a real-time and cost-effective manner. In this paper, a mathematical model for shutdown pressure evolution is developed considering the effects of wellbore friction, perforation friction and fluid loss in fractures. An efficient numerical simulation method is established by using the method of characteristics. Based on this… More >

Xiangqun Li^1,*, Jiawen Liang², Jinyu Zhu², Shengping Shi², Fangyu Ding², Jianpeng Sun², Bo Liu²

Energy Engineering, Vol.121, No.1, pp. 203-219, 2024, DOI:10.32604/ee.2023.029295

Abstract To solve the problems of a few optical fibre line fault samples and the inefficiency of manual communication optical fibre fault diagnosis, this paper proposes a communication optical fibre fault diagnosis model based on variational modal decomposition (VMD), fuzzy entropy (FE) and fuzzy clustering (FC). Firstly, based on the OTDR curve data collected in the field, VMD is used to extract the different modal components (IMF) of the original signal and calculate the fuzzy entropy (FE) values of different components to characterize the subtle differences between them. The fuzzy entropy of each curve is used as the feature vector, which… More >

Hua Leng¹, Silin He², Jian Qiu³, Feng Liu^4,*, Xinfei Huang⁴, Jiran Zhu²

Energy Engineering, Vol.121, No.1, pp. 77-94, 2024, DOI:10.32604/ee.2023.028340

Abstract The distribution network exhibits complex structural characteristics, which makes fault localization a challenging task. Especially when a branch of the multi-branch distribution network fails, the traditional multi-branch fault location algorithm makes it difficult to meet the demands of high-precision fault localization in the multi-branch distribution network system. In this paper, the multi-branch mainline is decomposed into single branch lines, transforming the complex multi-branch fault location problem into a double-ended fault location problem. Based on the different transmission characteristics of the fault-traveling wave in fault lines and non-fault lines, the endpoint reference time difference matrix S and the fault time difference… More >