Article
Energy & Fuels
Fuqiang Xu, Tianshou Ma, Yijia Tang, Xianzhi Song, Yu Shi
Summary: Enhanced geothermal system with vertical multi-fractures has potential as a heat extraction method. A new analytical model for fluid flow and heat transfer in these systems was proposed and validated, with analysis on the impact of parameters on heat extraction efficiency.
ENERGY SOURCES PART A-RECOVERY UTILIZATION AND ENVIRONMENTAL EFFECTS
(2021)
Article
Thermodynamics
Kaixuan Wang, Zaobao Liu, Tao Zeng, Fei Wang, Wanqing Shen, Jianfu Shao
Summary: This paper investigates the heat extraction performance of an enhanced geothermal system (EGS) under the influence of injection-production parameters and reservoir properties. A thermal-hydro-mechanical (THM) coupled model is used to quantify the complicated heat extraction process, and three-dimensional geothermal reservoir models are established to study the impact of fracture numbers. The results show the importance of optimizing fractures and the dominance of injection mass flow rate, fracture permeability, and injection temperature in affecting heat extraction performance. The findings have practical implications for the efficient construction and operation of EGS.
APPLIED THERMAL ENGINEERING
(2022)
Article
Green & Sustainable Science & Technology
Chenghao Zhong, Tianfu Xu, Yilong Yuan, Bo Feng, Han Yu
Summary: This study investigates the feasibility and potential of constructing a geothermal power plant in the Gonghe Basin in China. Through the use of a multiple interacting continua approach, the transport of heat and fluid within a high-temperature fractured geothermal reservoir is accurately analyzed. The proposed enhanced geothermal system shows promising power production performance and can contribute to reducing greenhouse gas emissions.
JOURNAL OF CLEANER PRODUCTION
(2022)
Article
Engineering, Geological
Yuedu Chen, Zhihong Zhao, Huan Peng
Summary: This study investigates the impact of intersected fractures on heat transfer in geothermal systems, finding that rough dead-end fractures enhance heat transfer and increasing the intersected angle is beneficial for heat production, while enlarging the aperture has little effect.
JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING
(2022)
Article
Thermodynamics
M. Soltani, Pooya Farzanehkhameneh, Farshad Moradi Kashkooli, Armughan Al-Haq, Jatin Nathwani
Summary: The study optimized parameters of geothermal heat pump (GHP) system using genetic algorithm, reducing installation costs and improving energy efficiency over a ten-year simulation. Ethylene glycol was identified as the preferred circulating fluid for significant energy consumption reduction.
ENERGY CONVERSION AND MANAGEMENT
(2021)
Article
Thermodynamics
Xueling Liu, Yuanming Wang, Shuai Li, Jiansheng Wang
Summary: This study constructs a three-dimensional physical model of a single fracture with undulated surface morphology in hot dry rock to investigate the convection heat transfer characteristics of supercritical CO2. The results show that the local convection heat transfer coefficients at different positions in the fracture exhibit opposite variation trends, and increase with the decrease of flow rate, the increase of pressure and inlet temperature.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Green & Sustainable Science & Technology
Renhui He, Guan Rong, Jie Tan, Kok-Kwang Phoon, Junsong Quan
Summary: The roughness of fractured surfaces significantly affects fluid flow and heat transfer in fractured rocks. This study compares the role of rough-walled fractures with parallel plates in modeling Enhanced Geothermal Systems (EGS) and highlights the importance of fracture orientation in thermal recovery performance.
Article
Thermodynamics
Meng Cao, Mukul M. Sharma
Summary: In this paper, a computationally efficient model is proposed to simulate fracture propagation, fluid flow, and heat transfer in naturally fractured geothermal reservoirs. The integrated simulator combines the displacement discontinuity method (DDM) and a general Green's function solution, resulting in a faster and accurate solution. Validation and parametric studies show the importance of optimizing the connectivity and complexity of the fracture network.
Article
Thermodynamics
Xiaotian Wu, Yingchun Li, Tianjiao Li, Chun'an Tang
Summary: Fixed-plane-perforation fracturing (PFFP) has been introduced to enhance geothermal system (EGS) and has shown potential to stimulate longer fractures and achieve higher heat extraction compared to single-perforation fracturing (SPF). By using an improved sensitivity indicator, the injection rate is found to significantly affect the fracture network area, while the in-situ stress difference has the greatest impact on heat extraction.
APPLIED THERMAL ENGINEERING
(2023)
Article
Engineering, Chemical
Yuchao Zeng, Fangdi Sun, Haizhen Zhai
Summary: The vertical permeability heterogeneity in stratified formations significantly influences the electricity generation performance of enhanced geothermal systems, affecting water production rate, electric power, reservoir impedance, and pump power. However, vertical permeability heterogeneity is not the main factor affecting injection pressure and energy efficiency in the system.
Article
Thermodynamics
Ling Wang, Zhenjiao Jiang, Chengying Li
Summary: The spatial arrangement of fractures in geothermal systems plays a crucial role in determining the efficiency of heat production. However, characterizing complex fracture structures is challenging due to limited information in deep geothermal reservoirs. This study explores the macroscopic and microscopic characteristics of fractures and evaluates their impact on flow, heat transport, and heat production. The findings suggest that the macroscopic structure influences heat production through density-driven flow, while the microscopic structure affects flow paths, cross-sectional flow area, and density-driven flow. A sensitivity analysis highlights the importance of characterizing the macroscopic structure followed by estimating the mean and correlation length of fracture apertures in enhanced geothermal systems.
Article
Mechanics
Jiaqi Chen, Xikun Wang, Hongbo Shi, Jin-Hua Si
Summary: The present study experimentally investigates the flow characteristics of a fully developed circular water jet over a wide range of Reynolds numbers, impinging heights, and impinging angles. The study focuses on the velocity distribution along the jet centerline and the flow structure in the uphill and downhill regions. The results reveal that the velocity profiles of the impinging jet maintain self-similarity before impingement on the bottom plate. A semi-empirical equation has been developed for the jet centerline velocity based on the obtained experimental data and theoretical analysis. For the oblique impinging jet, the position of the stagnation point highly depends on the jet height and impinging angle, but it is insensitive to the Reynolds number. The existence of a recirculation zone in the uphill direction is influenced by pressure gradients and shear forces, whose size and position depend on the impinging height, impinging angle, and Reynolds number. Different flow states are observed for relatively small impinging heights near the geometric center in the downhill region. The flow patterns for various Reynolds numbers and impinging heights are self-similar in the downhill region at a/d = 6.
Article
Engineering, Geological
Chuanyin Jiang, Xiaoguang Wang, Fengshou Zhang, Kai Deng, Qinghua Lei
Summary: This study investigates the impact of in situ stresses, injection pressure, and temperature on fracture activation and induced seismicity in fractured geothermal reservoirs. The results reveal that the in situ stress state plays a fundamental role in controlling seismicity occurrence, while injection-induced fluid pressurization and thermal perturbation act as triggering factors. Seismic events mainly occur near the injection well and along the main streamlines of fluid flow. Additionally, the injection pressure and temperature strongly affect the long-term thermal energy output of the reservoir.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Green & Sustainable Science & Technology
Guojun Yu, Huyu Li, Cong Liu, Wan Cheng, Huijin Xu
Summary: In this paper, a flyover-crossing fracture (FCF) configuration was proposed to enhance the efficiency of enhanced geothermal systems (EGS). A 3D transient thermal-hydraulic model was used to analyze the heat extraction of the FCF-EGS and examine the effects of intersection angles on heat and mass transfer. The results showed that the FCF-EGS had higher production temperature and thermal power output than the conventional double-horizontal-well EGS, and the heat extraction capacity increased with the intersection angle. The study also found that a 90-degree cross-angle FCF had the best heat extraction performance.
Review
Green & Sustainable Science & Technology
S. Li, S. Wang, H. Tang
Summary: This work provides a comprehensive review of fracture stimulation in enhanced geothermal systems, including hydraulic stimulation mechanisms, design strategies, and measurement tools. It compares the impacts of different hydraulic stimulation mechanisms on the performance of enhanced geothermal systems and analyzes the hydraulic stimulation design strategies in 19 representative projects worldwide. The difference between hydraulic stimulation operations in geothermal reservoirs and those in oil/gas fields is clarified, aiming to provide useful guidelines for both theoretical research and field operations.
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2022)
Article
Thermodynamics
Yong Cheng, Fukai Song, Lei Fu, Saishuai Dai, Zhiming Yuan, Atilla Incecik
Summary: This paper investigates the accessibility of wave energy absorption by a dual-pontoon floating breakwater integrated with hybrid-type wave energy converters (WECs) and proposes a hydraulic-pneumatic complementary energy extraction method. The performance of the system is validated through experiments and comparative analysis.
Article
Thermodynamics
Jing Gao, Chao Wang, Zhanwu Wang, Jin Lin, Runkai Zhang, Xin Wu, Guangyin Xu, Zhenfeng Wang
Summary: This study aims to establish a new integrated method for biomass cogeneration project site selection, with a focus on the application of the model in Henan Province. By integrating Geographic Information System and Multiple Criterion Decision Making methods, the study conducts site selection in two stages, providing a theoretical reference for the construction of biomass cogeneration projects.
Article
Thermodynamics
Mert Temiz, Ibrahim Dincer
Summary: The current study presents a hybrid small modular nuclear reactor and solar-based system for sustainable communities, integrating floating and bifacial photovoltaic arrays with a small modular reactor. The system efficiently generates power, hydrogen, ammonia, freshwater, and heat for residential, agricultural, and aquaculture facilities. Thermodynamic analysis shows high energy and exergy efficiencies, as well as large-scale ammonia production meeting the needs of metropolitan areas. The hybridization of nuclear and solar technologies offers advantages of reliability, environmental friendliness, and cost efficiency compared to renewable-alone and fossil-based systems.
Editorial Material
Thermodynamics
Wojciech Stanek, Wojciech Adamczyk
Article
Thermodynamics
Desheng Xu, Yanfeng Li, Tianmei Du, Hua Zhong, Youbo Huang, Lei Li, Xiangling Duanmu
Summary: This study investigates the optimization of hybrid mechanical-natural ventilation for smoke control in complex metro stations. The results show that atrium fires are more significantly impacted by outdoor temperature variations compared to concourse/platform fires. The gathered high-temperature smoke inside the atrium can reach up to 900 K under a 5 MW train fire energy release. The findings provide crucial engineering insights into integrating weather data and adaptable ventilation protocols for smoke prevention/mitigation.
Article
Thermodynamics
Da Guo, Heping Xie, Mingzhong Gao, Jianan Li, Zhiqiang He, Ling Chen, Cong Li, Le Zhao, Dingming Wang, Yiwei Zhang, Xin Fang, Guikang Liu, Zhongya Zhou, Lin Dai
Summary: This study proposes a new in-situ pressure-preserved coring tool and elaborates its pressure-preserving mechanism. The experimental and field test results demonstrate that this tool has a high pressure-preservation capability and can maintain a stable pressure in deep wells. This study provides a theoretical framework and design standards for the development of similar technologies.
Article
Thermodynamics
Aolin Lai, Qunwei Wang
Summary: This study assesses the impact of China's de-capacity policy on renewable energy development efficiency (REDE) using the Global-MSBM model and the difference-in-differences method. The findings indicate that the policy significantly enhances REDE, promoting technological advancements and marketization. Moreover, regions with stricter environmental regulations experience a higher impact.
Article
Thermodynamics
Mostafa Ghasemi, Hegazy Rezk
Summary: This study utilizes fuzzy modeling and optimization to enhance the performance of microbial fuel cells (MFCs). By simulating and analyzing experimental data sets, the ideal parameter values for increasing power density, COD elimination, and coulombic efficiency were determined. The results demonstrate that the fuzzy model and optimization methods can significantly improve the performance of MFCs.
Article
Thermodynamics
Zhang Ruan, Lianzhong Huang, Kai Wang, Ranqi Ma, Zhongyi Wang, Rui Zhang, Haoyang Zhao, Cong Wang
Summary: This paper proposes a grey box model for fuel consumption prediction of wing-diesel hybrid vessels based on feature construction. By using both parallel and series grey box modeling methods and six machine learning algorithms, twelve combinations of prediction models are established. A feature construction method based on the aerodynamic performance of the wing and the energy relationship of the hybrid system is introduced. The best combination is obtained by considering the root mean square error, and it shows improved accuracy compared to the white box model. The proposed grey box model can accurately predict the daily fuel consumption of wing-diesel hybrid vessels, contributing to operational optimization and the greenization and decarbonization of the shipping industry.
Article
Thermodynamics
Huayi Chang, Nico Heerink, Junbiao Zhang, Ke He
Summary: This study examines the interaction between off-farm employment decisions between couples and household clean energy consumption in rural China, and finds that two-paycheck households are more likely to consume clean energy. The off-farm employment of women is a key factor driving household clean energy consumption to a higher level, with wage-employed wives having a stronger influence on these decisions than self-employed ones.
Article
Thermodynamics
Hanguan Wen, Xiufeng Liu, Ming Yang, Bo Lei, Xu Cheng, Zhe Chen
Summary: Demand-side management is crucial to smart energy systems. This paper proposes a data-driven approach to understand the relationship between energy consumption patterns and household characteristics for better DSM services. The proposed method uses a clustering algorithm to generate optimal customer groups for DSM and a deep learning model for training. The model can predict the possibility of DSM membership for a given household. The results demonstrate the usefulness of weekly energy consumption data and household socio-demographic information for distinguishing consumer groups and the potential for targeted DSM strategies.
Article
Thermodynamics
Xinglan Hou, Xiuping Zhong, Shuaishuai Nie, Yafei Wang, Guigang Tu, Yingrui Ma, Kunyan Liu, Chen Chen
Summary: This study explores the feasibility of utilizing a multi-level horizontal branch well heat recovery system in the Qiabuqia geothermal field. The research systematically investigates the effects of various engineering parameters on production temperature, establishes mathematical models to describe their relationships, and evaluates the economic viability of the system. The findings demonstrate the significant economic feasibility of the multi-level branch well system.
Article
Thermodynamics
Longxin Zhang, Songtao Wang, Site Hu
Summary: This investigation reveals the influence of tip leakage flow on the modern transonic rotor and finds that the increase of tip clearance size leads to a decline in rotor performance. However, an optimal tip clearance size can extend the rotor's stall margin.
Article
Thermodynamics
Kristian Gjoka, Behzad Rismanchi, Robert H. Crawford
Summary: This paper proposes a framework for assessing the performance of 5GDHC systems and demonstrates it through a case study in a university campus in Melbourne, Australia. The results show that 5GDHC systems are a cost-effective and environmentally viable solution in mild climates, and their successful implementation in Australia can create new market opportunities and potential adoption in other countries with similar climatic conditions.
Article
Thermodynamics
Jianwei Li, Guotai Wang, Panpan Yang, Yongshuang Wen, Leian Zhang, Rujun Song, Chengwei Hou
Summary: This study proposes an orientation-adaptive electromagnetic energy harvester by introducing a rotatable bluff body, which allows for self-regulation to cater for changing wind flow direction. Experimental results show that the output power of the energy harvester can be greatly enhanced with increased rotatory inertia of the rotating bluff body, providing a promising solution for harnessing wind-induced vibration energy.