Article
Thermodynamics
Galip Kaltakkiran, Halil Ibrahim Akolas, Kadir Bakirci
Summary: In this study, classical and electronically controlled external EGR cooling systems are designed to investigate the effect of EGR rates and EGRout gas temperatures on engine performance and energy efficiency. The results show that the EGR rate has a more dominant effect on combustion performance and efficiency, and recommended to select the optimum EGR rate and EGRout gas temperature for engine performance and energy efficiency.
ENERGY CONVERSION AND MANAGEMENT
(2023)
Article
Energy & Fuels
Kangmin Ju, Joonsuk Kim, Jungsoo Park
Summary: This study demonstrates the feasibility of using a diesel engine as a power generator for electric vehicles, and shows that downsized diesel engines have the potential to improve power output performance.
Article
Thermodynamics
Constantine D. Rakopoulos, Dimitrios C. Rakopoulos, Dimitrios C. Kyritsis, Eleftherios C. Andritsakis, George C. Mavropoulos
Summary: This study is based on a validated combustion model and predicts the performance and emissions of spark-ignition engines. The model is extended by considering exergy terms and applied to experimental test results. The study provides detailed information on chemical exergy, irreversibility, and exergy losses.
Article
Green & Sustainable Science & Technology
Samad Jafarmadar, Seyed Reza Amini Niaki
Summary: This study investigated the effect of EGR amounts and temperatures on diesel/biodiesel combustion in a turbocharged direct injection diesel engine from the perspective of Exergy analysis. Results showed that higher EGR implementation at higher temperatures reduced accumulative work and combustion exergies, while increasing fuel and heat loss exergies.
ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY
(2021)
Article
Engineering, Multidisciplinary
Huseyin Gurbuz, Tarkan Sandalci
Summary: The effects of methane intake port injection and direct diesel injection on emissions and combustion in a light-duty RCCI engine were investigated numerically. The study found that these parameters have significant impacts on performance and emissions.
ALEXANDRIA ENGINEERING JOURNAL
(2023)
Article
Thermodynamics
Qiang Guo, Jie Liu, Binyang Wu, Yize Liu
Summary: This paper focuses on the multi-objective optimization of fuel injection parameters, combustion chamber geometry parameters, and engine operating parameters of a double-layer combustion chamber. The NSGA-II genetic algorithm and the KIVA-3V program are combined to optimize three objectives, including indicated specific fuel consumption (ISFC) rate, NOx, and soot emissions. The optimization simultaneously considers 10 engine parameters. The results reveal the trade-off relationship between NOx and soot emissions and ISFC, and demonstrate the effectiveness of delayed injection timing and Exhaust Gas Recirculation (EGR) in reducing NOx emissions.
Article
Thermodynamics
Serhat Gunaydin, Ahmet Uyumaz, Tolga Kocakulak, Sertac Cosman, Hamit Solmaz, Fatih Aksoy
Summary: Diesel's ignition characteristics can be improved by using dibutyl maleate as an additive. Experimental results showed that the addition of dibutyl maleate increased in-cylinder pressure and ignition delay, while reducing combustion duration and thermal efficiency. The usage of dibutyl maleate also led to lower hydrocarbon and soot emissions, but increased carbon monoxide, carbon dioxide, and nitrogen oxides emissions.
APPLIED THERMAL ENGINEERING
(2024)
Article
Chemistry, Multidisciplinary
Diming Lou, Lulu Kang, Yunhua Zhang, Liang Fang, Chagen Luo
Summary: This paper studied the effect of EGR combined with SCR on the NOx emission characteristics of a heavy-duty diesel engine through engine bench testing. The results showed that the combination of EGR and SCR has a significant impact on NOx reduction rate, but has little effect on NO2 emission reduction. The study also found that the opening of the EGR valve and the ammonia NOx molar ratio have an influence on the NOx reduction rate, with different effects at different engine speeds.
Article
Energy & Fuels
Jichao Liang, Quanchang Zhang, Zheng Chen, Zunqing Zheng, Chao Yang, Qixin Ma
Summary: The use of Tetrahydrofuran (THF) and ethanol as co-solvents for diesel fuel can increase combustion efficiency and reduce emissions, especially at low EGR rates, in diesel engine tests.
Article
Chemistry, Applied
Ahmad O. Hasan, Ahmed I. Osman, Ala'a H. Al-Muhtaseb, Hani Al-Rawashdeh, Ahmad Abu-jrai, Riad Ahmad, Mohamed R. Gomaa, Tanmay J. Deka, David W. Rooney
Summary: The study found that blended methanol can reduce HC and CO emissions in tailpipe, but increase NOx emissions; smoke emissions significantly decrease as the percentage of methanol in blends increases. Pure diesel showed higher brake thermal efficiency and lower fuel consumption at all engine loads.
FUEL PROCESSING TECHNOLOGY
(2021)
Article
Thermodynamics
Xiongbo Duan, Zhengxin Xu, Xingyu Sun, Banglin Deng, Jingping Liu
Summary: This study investigated the effects of different ABE ratios and injection timings on the combustion and emissions behaviors of diesel engines fueled with ABE/diesel blended fuel. The results showed that the combustion process of diesel engines fueled with ABE/diesel fuel was strongly affected by injection timing and EGR.
Article
Thermodynamics
Donghui Qi, Li Ma, Ru Chen, Xiaoxuan Jin, Manyao Xie
Summary: The study found that increasing EGR rates led to higher BSFC and lower BTE, while ternary blends showed better performance in some aspects but also came with some trade-offs.
APPLIED THERMAL ENGINEERING
(2021)
Article
Energy & Fuels
M. Mourad, Khaled R. M. Mahmoud, El-Sadek H. Noureldeen
Summary: This research focuses on the impact of exhaust gas recirculation (EGR) on diesel engine performance and emissions fueled with preheated biodiesel fuel. The study finds that under certain conditions, EGR can help reduce pollutants emitted from the diesel engine, especially NOx emissions.
Article
Environmental Sciences
Bibin Chidambaranathan, Devan Ponnusamy Kumarasami, Sheeja Raghavan, Madhu Sundaram
Summary: The study investigates the effects of exhaust gas recirculation (EGR) on a diesel engine fueled with punnai oil biodiesel mixed with diesel (B20). The combination of punnai oil biodiesel with EGR enhances the maximum heat release rate and combustion pressure in the engine. The findings show that the premixed burning fractions are higher and diffusion combustion fractions are lower at all engine loads. The B20 blend with 10% EGR flow rate reduces CO and UHC emissions, increases CO2 emissions, decreases NOx emissions, and slightly increases smoke opacity compared to standard diesel fuel.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Thermodynamics
Hongqing Feng, Xiaofan Chen, Liangliang Sun, Ruixiu Ma, Xiuxia Zhang, Lijun Zhu, Chaohe Yang
Summary: This paper systematically examines the influences of methanol/n-butanol/biodiesel/diesel blend fuels on the performance of turbocharged diesel engines. The results show that the use of blended fuels increases cylinder peak pressure, prolongs ignition delay, and improves fuel consumption rate and brake thermal efficiency. Multi-blend fuels reduce soot emission while slightly increasing NOx emission. EGR and delayed injection timing are effective in reducing NOx emissions.
Article
Energy & Fuels
Dimitrios C. Rakopoulos, Constantine D. Rakopoulos, Evangelos G. Giakoumis, George M. Kosmadakis
Summary: This study developed a comprehensive, quasi-dimensional, two-zone combustion model to predict the combustion characteristics, performance, and emissions of high-speed spark-ignition engines. The validated model showed good agreement with experimental data, providing insights into engine performance and emission attributes. The results shed light on the underlying physical and chemical mechanisms influencing SI engine performance and emissions.
JOURNAL OF ENERGY ENGINEERING
(2021)
Review
Energy & Fuels
Theodoros C. Zannis, John S. Katsanis, Georgios P. Christopoulos, Elias A. Yfantis, Roussos G. Papagiannakis, Efthimios G. Pariotis, Dimitrios C. Rakopoulos, Constantine D. Rakopoulos, Athanasios G. Vallis
Summary: This paper reviews the contemporary exhaust gas treatment systems (EGTS) used in shipping for SOx, PM, and NOx emission control. Various after-treatment technologies are analyzed, and their operational principles, performance characteristics, and investment and operation details are thoroughly explained. The effectiveness of different technologies in reducing NOx emissions is compared, and actual data on the installation and cost of seawater scrubbers are provided. The study concludes that closed-loop wet scrubbers with NaOH solution are the most effective in reducing SOx emissions, while SCR systems can effectively reduce NOx emissions and comply with IMO Tier III limits.
Article
Thermodynamics
Constantine D. Rakopoulos, Dimitrios C. Rakopoulos, Dimitrios C. Kyritsis, Eleftherios C. Andritsakis, George C. Mavropoulos
Summary: This study is based on a validated combustion model and predicts the performance and emissions of spark-ignition engines. The model is extended by considering exergy terms and applied to experimental test results. The study provides detailed information on chemical exergy, irreversibility, and exergy losses.
Article
Energy & Fuels
Theodoros C. Zannis, Roussos G. Papagiannakis, Efthimios G. Pariotis, Dimitrios C. Rakopoulos, Athanasios G. Vallis
Summary: This theoretical study examines the impact of intake-air nitrogen enrichment on the performance and emissions of a high-speed direct injection diesel engine. The results show that increasing intake-air nitrogen content can achieve NO emissions-free operation, but it leads to higher levels of soot emissions. In addition, using biodiesel such as RME under certain conditions can reduce both soot and NO emissions.
JOURNAL OF ENERGY ENGINEERING
(2022)
Article
Thermodynamics
George Kosmadakis, Panagiotis Neofytou
Summary: This article examines an alternative waste heat recovery solution for ships, which relies on a reversible unit that switches between electricity production and steam generation. By utilizing the waste heat from the engine's cooling water, the reversible unit is able to increase the capacity factor. The study shows that the reversible unit outperforms individual solutions and achieves significant fuel savings.
Review
Chemistry, Multidisciplinary
Maria Fotopoulou, Stefanos Petridis, Ioannis Karachalios, Dimitrios Rakopoulos
Summary: This paper reviews the algorithms for Distribution System State Estimation (DSSE), focusing on their specific requirements, mathematical formulation, existing model-based and data-driven approaches, and recommended solutions. The paper also highlights DSSE applications and future trends, emphasizing the business-related aspects.
APPLIED SCIENCES-BASEL
(2022)
Article
Energy & Fuels
George M. Kosmadakis, Dimitrios C. Rakopoulos, Constantine D. Rakopoulos
Summary: The effect of two mechanisms on the cyclic variability of a lean methane-hydrogen fueled SI engine was investigated using computational fluid dynamics (CFD) simulations. The first mechanism involves gas turbulent properties near the spark plug, while the second mechanism involves fuel mass variation per cycle. Linear regression and Monte Carlo-based approaches were used to analyze engine performance and emissions. The results showed that the first mechanism significantly affects the initial flame propagation, while the second mechanism affects the combustion process and CO emissions with high variability.
JOURNAL OF ENERGY ENGINEERING
(2023)
Article
Chemistry, Analytical
Maria Fotopoulou, Dimitrios Rakopoulos, Stefanos Petridis
Summary: This paper introduces an optimal Decision Support System (DSS) to assist microgrid operators in handling various emergencies and optimizing the autonomy of the microgrid while prioritizing renewable energy production. The DSS is aligned with the ongoing energy transition and considers multiple types of Distributed Energy Resources (DER), including Renewable Energy Sources (RES) and Battery Energy Storage Systems (BESS) that can only be charged with renewable energy.
Article
Green & Sustainable Science & Technology
Myrto Zeneli, Alessandro Bellucci, Gianfranco Sabbatella, Maria Fotopoulou, Vasilis Apostolopoulos, Panagiotis Stamatopoulos, Daniele M. M. Trucchi, Aristeidis Nikolopoulos, Dimitrios Rakopoulos
Summary: Dielectric microspacers (DMS) are used to achieve a fixed gap distance between the emitter and the PV cell of a near-field thermophotovoltaic converter. This study investigates the integration of DMS technology into a hybrid thermionic-photovoltaic converter operating at ultra-high temperatures without the risk of overheating and mechanical failure. A 3-D CFD model was developed to simulate the thermal behavior of the system under different conditions. Results show that DMS pattern does not affect thermal performance, but mechanical failure is possible at high cathode temperatures.
Article
Energy & Fuels
Marika Pilou, George Kosmadakis, George Meramveliotakis
Summary: This study describes an integrated numerical model for a renewable-energy-based system that meets a building's heating, cooling, and hot water needs. The model includes a vapor compression multi-source heat pump, PVT collectors, thermal energy storage, and water tanks. The model's performance is validated using measurements from a pilot operation in Athens and it has shown to accurately predict the building's energy system performance.
Article
Energy & Fuels
Renos Rotas, Maria Fotopoulou, Panagiotis Drosatos, Dimitrios Rakopoulos, Nikos Nikolopoulos
Summary: This study assesses the annual performance improvement of two actual building spaces retrofitted with Adaptive Dynamic Building Envelopes (ADBEs) and evaluates their potential to contribute to the electricity and heating load of the spaces. The results demonstrate that the ADBE system can significantly benefit the energy consumption of the buildings in Cardiff and Grevena.
Review
Computer Science, Information Systems
David Cervero, Maria Fotopoulou, Jesus Munoz-Cruzado, Dimitrios Rakopoulos, Fotis Stergiopoulos, Nikos Nikolopoulos, Spyros Voutetakis, Jose Francisco Sanz
Summary: The paper provides a practical review of the solid state transformer (SST), which is considered to be the dominant solution for the changing architecture of electricity networks. It presents the main functionalities and possible applications of SST, including smart grids, data centres, railways, and offshore wind farms. The analysis of SST prototypes and future trends and challenges in wider implementation of SST technology in the electrical grid are also discussed.
Article
Thermodynamics
Anastasios Skiadopoulos, George Kosmadakis, Steven Lecompte, Michel De Paepe, Dimitrios Manolakos
Summary: This paper presents a novel semi-empirical thermodynamic model for simulating two-phase expansion in twin-screw expanders. The model calculates the values of unknown parameters through a calibration-optimization process and performs simulations for various operating conditions. The results indicate that the vapor quality at the suction port of the expander is the main factor affecting its efficiency.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2023)
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.
