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A review of developments, trends, and challenges in synthesis, design, and operation optimization of ship energy systems is presented in this article. For better understanding of the context of this review, pertinent terms are defined, including the three levels of optimization: synthesis, design, and operation (SDO). The static and dynamic optimization problems are stated mathematically in single- and multiobjective form. The need for intertemporal optimization is highlighted. The developments in ship energy systems optimization throughout the years is clearly presented by means of journal articles, giving the main characteristics of each article. After the review of what has been done up to now, ideas for future work are given. Further research needs for optimization of ship energy systems are mentioned: further development of methodology for synthesis optimization and SDO optimization, including transients, uncertainty, reliability, and maintenance scheduling. Hints are given for expansion of the system border in order to include aspects belonging to other disciplines, such as electrical and control engineering as well as hull and propulsor optimization, thus, opening a way to the holistic ship optimization.
Christos A. Frangopoulos. Developments, Trends, and Challenges in Optimization of Ship Energy Systems. Applied Sciences 2020, 10, 4639 .
AMA StyleChristos A. Frangopoulos. Developments, Trends, and Challenges in Optimization of Ship Energy Systems. Applied Sciences. 2020; 10 (13):4639.
Chicago/Turabian StyleChristos A. Frangopoulos. 2020. "Developments, Trends, and Challenges in Optimization of Ship Energy Systems." Applied Sciences 10, no. 13: 4639.
Christos A. Frangopoulos; Gerasimos Theotokatos; Francesco Baldi. Special issue dedicated to MOSES2019: 2nd international conference on modelling and optimisation of ship energy systems. Energy 2020, 198, 117363 .
AMA StyleChristos A. Frangopoulos, Gerasimos Theotokatos, Francesco Baldi. Special issue dedicated to MOSES2019: 2nd international conference on modelling and optimisation of ship energy systems. Energy. 2020; 198 ():117363.
Chicago/Turabian StyleChristos A. Frangopoulos; Gerasimos Theotokatos; Francesco Baldi. 2020. "Special issue dedicated to MOSES2019: 2nd international conference on modelling and optimisation of ship energy systems." Energy 198, no. : 117363.
Fuel expenses constitute the largest part of the operating cost of a merchant ship. Integrated energy systems that cover all energy loads with low fuel consumption, while being economically feasible, are increasingly studied and installed. Due to the large variety of possible configurations, design specifications, and operating conditions that change with time, the application of optimization methods is imperative. Designing the system for nominal conditions only is not sufficient. Instead, intertemporal optimization needs to be performed that can be static or dynamic. In the present article, intertemporal static and dynamic optimization problems for the synthesis, design, and operation (SDO) of integrated ship energy systems are stated mathematically and the solution methods are presented, while case studies demonstrate the applicability of the methods and also reveal that the optimal solution may defer significantly from the solutions suggested with the usual practice. While in other works, the SDO optimization problems are usually solved by two- or three-level algorithms; single-level algorithms are developed and applied here, which tackle all three aspects (S, D, and O) concurrently. The methods can also be applied on land installations, e.g., power plants, cogenerations systems, etc., with proper modifications.
George N. Sakalis; George J. Tzortzis; Christos A. Frangopoulos. Intertemporal Static and Dynamic Optimization of Synthesis, Design, and Operation of Integrated Energy Systems of Ships. Energies 2019, 12, 893 .
AMA StyleGeorge N. Sakalis, George J. Tzortzis, Christos A. Frangopoulos. Intertemporal Static and Dynamic Optimization of Synthesis, Design, and Operation of Integrated Energy Systems of Ships. Energies. 2019; 12 (5):893.
Chicago/Turabian StyleGeorge N. Sakalis; George J. Tzortzis; Christos A. Frangopoulos. 2019. "Intertemporal Static and Dynamic Optimization of Synthesis, Design, and Operation of Integrated Energy Systems of Ships." Energies 12, no. 5: 893.
An overview of recent developments, trends and challenges in the synthesis, design and operation optimization of energy systems is presented in this manuscript. The static and dynamic optimization problems are stated mathematically, solution methods are mentioned in brief and classification of optimization problems based on the presence and treatment of time is presented. Examples of objective functions in single-objective optimization are given and the need for multi-objective optimization is highlighted. Special reference is made to Prof. Szargut's early statement about the need for optimization with ecological concerns. Emphasis is given to optimal synthesis of energy systems, a subject that is still between (or combines) art and science/technology. Furthermore, it is interesting to note that optimization is applied also during the development of models of systems. Hints are given on further considerations and research needs in subjects such as global optimization, as well as optimization with uncertainty, reliability, maintenance and social aspects. Examples of algorithms appearing in recent publications are given as an indication of the related strong activity. The manuscript closes with general remarks and a rather comprehensive, even though not exhaustive, list of references.
Christos A. Frangopoulos. Recent developments and trends in optimization of energy systems. Energy 2018, 164, 1011 -1020.
AMA StyleChristos A. Frangopoulos. Recent developments and trends in optimization of energy systems. Energy. 2018; 164 ():1011-1020.
Chicago/Turabian StyleChristos A. Frangopoulos. 2018. "Recent developments and trends in optimization of energy systems." Energy 164, no. : 1011-1020.
A multi-criteria approach is presented for the assessment of alternative means for covering the energy needs (electricity and heat) of an industrial unit, taking into consideration sustainability aspects. The procedure is first described in general terms: proper indicators are defined; next they are grouped in order to form sub-indices, which are then used to determine the composite sustainability index. The procedure is applied for the evaluation of three alternative systems. The three systems are placed in order of preference, which depends on the criteria used. In addition to conclusions reached as a result of the particular case study, recommendations for future work are given.
Christos A. Frangopoulos; Despoina E. Keramioti. Multi-Criteria Evaluation of Energy Systems with Sustainability Considerations. Entropy 2010, 12, 1006 -1020.
AMA StyleChristos A. Frangopoulos, Despoina E. Keramioti. Multi-Criteria Evaluation of Energy Systems with Sustainability Considerations. Entropy. 2010; 12 (5):1006-1020.
Chicago/Turabian StyleChristos A. Frangopoulos; Despoina E. Keramioti. 2010. "Multi-Criteria Evaluation of Energy Systems with Sustainability Considerations." Entropy 12, no. 5: 1006-1020.
In a previous work by the authors, the performance of a plant based on solid oxide fuel cells (SOFC) which produces its own fuel by solar energy had been studied. The system consists not only of the fuel/electrolytic cell unit and the gas turbine but also of compressors, pumps, heat exchangers, etc. In the aforementioned work, a “workable” synthesis (structure) of the system had been considered, which is not necessarily the best one. In the meantime, an attempt has been made to improve on the structure and, if possible, to determine the one with the best performance under certain conditions. For this purpose, the Pinch method together with exergy analysis has been applied, while the performance of the system for any configuration has been determined by a simulation model. The results of this work are presented in this article.
Nectarios C Monanteras; Christos A Frangopoulos. Towards synthesis optimization of a fuel-cell based plant. Energy Conversion and Management 1999, 40, 1733 -1742.
AMA StyleNectarios C Monanteras, Christos A Frangopoulos. Towards synthesis optimization of a fuel-cell based plant. Energy Conversion and Management. 1999; 40 (15-16):1733-1742.
Chicago/Turabian StyleNectarios C Monanteras; Christos A Frangopoulos. 1999. "Towards synthesis optimization of a fuel-cell based plant." Energy Conversion and Management 40, no. 15-16: 1733-1742.