scholarly journals Intertemporal Static and Dynamic Optimization of Synthesis, Design, and Operation of Integrated Energy Systems of Ships

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 893 ◽  
Author(s):  
George Sakalis ◽  
George Tzortzis ◽  
Christos Frangopoulos
Keyword(s):  
Dynamic Optimization ◽  
Power Plants ◽  
Optimization Problems ◽  
Operating Cost ◽  
Optimal Solution ◽  
Energy Systems ◽  
Operating Conditions ◽  
Usual Practice ◽  
Integrated Energy Systems ◽  
Synthesis Design

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.

scholarly journals Development of a method for dynamic optimization of integrated energy systems of ships

2018 ◽  
Author(s):  
Γεώργιος Τζώρτζης
Keyword(s):  
Dynamic Optimization ◽  
Energy Systems ◽  
Integrated Energy Systems ◽  
Synthesis Design

Το αντικείμενο αυτής της Διατριβής είναι η ανάπτυξη μιας μεθόδου για τη δυναμική βελτιστοποίηση σύνθεσης, σχεδιασμού και λειτουργίας (Synthesis, Design and Operation, SDO) ολοκληρωμένων ενεργειακών συστημάτων πλοίων. Η συνήθης πρακτική της σύνθεσης, του σχεδιασμού και της λειτουργίας των ενεργειακών συστημάτων, ειδικά στη ναυτιλία, βασίζεται συνήθως σε συγκεκριμένους κανόνες καθώς και στην εμπειρία του σχεδιαστή. Επιπλέον, το σύστημα συχνά σχεδιάζεται σε πλήρες φορτίο υπό τη θεώρηση λειτουργίας σταθερής κατάστασης, ενώ η ‒εκτός σημείου σχεδιασμού‒ δυναμική συμπεριφορά του λαμβάνεται υπόψη μόνο αφότου το σύστημα έχει ήδη σχεδιαστεί. Στόχος αυτής της ερευνητικής δραστηριότητας είναι ο καθορισμός των τεχνο‒οικονομικά βέλτιστων λύσεων για τη σύνθεση, τον σχεδιασμό και τη λειτουργία ενεργειακών συστημάτων πλοίων, προκειμένου να καλυφθούν πλήρως οι διάφορες απαιτήσεις πρόωσης, ηλεκτρικής ενέργειας και θερμικής ενέργειας. Πραγματικά δυναμικά χαρακτηριστικά, όπως οι χρόνο‒ και χώρο‒μεταβαλλόμενες λειτουργικές απαιτήσεις σε σχέση με τις καιρικές συνθήκες και τα χρόνο‒μεταβαλλόμενα φορτία, ενσωματώνονται στα μοντέλα απόδοσης των συνιστωσών του συστήματος και κατά συνέπεια στη συνολική απόδοση του ολοκληρωμένου ενεργειακού συστήματος πλοίου, δημιουργώντας έτσι ένα καθαρά δυναμικό πρόβλημα βελτιστοποίησης.Για την ανάπτυξη της απαιτούμενης μεθοδολογίας ιδιαίτερη προσοχή δόθηκε στην κατασκευή κατάλληλων υπερδομών που απεικονίζουν όλες τις διαθέσιμες επιλογές σύνθεσης καθώς και όλες τις πιθανές διασυνδέσεις των συνιστωσών του ενεργειακού συστήματος. Για τη μοντελοποίηση του συστήματος στο σύνολό του χρησιμοποιείται μια μοντελοποιητική διαδικασία μεικτού ακεραίου προγραμματισμού, ενώ ακέραιες, στατικές και συνεχείς μεταβλητές χρησιμοποιούνται για τη μοντελοποίηση των επιπέδων της σύνθεσης του σχεδιασμού και της λειτουργίας, αντίστοιχα. Το γενικό πρόβλημα διατυπώνεται με χρήση ενός μαθηματικού φορμαλισμού Αλγεβρικό‒Διαφορικών Εξισώσεων ενώ κατάλληλες μέθοδοι δυναμικής βελτιστοποίησης, συνδυασμένες με μεθόδους μεικτού ακεραίου μαθηματικού προγραμματισμού, αναπτύσσονται και εφαρμόζονται. Όλα τα παραπάνω οδηγούν στην ανάπτυξη μιας μεθοδολογίας, η οποία, σε αντίθεση με τις συνήθεις μεθόδους που προτείνονται στη βιβλιογραφία, μπορεί να χαρακτηριστεί ως μια μέθοδος ενός επιπέδου που βελτιστοποιεί τα επίπεδα της σύνθεσης, του σχεδιασμού και της λειτουργίας ταυτόχρονα και δεν απαιτεί την πλήρωση ειδικών συνθηκών αποσύζευξης των επιπέδων του προβλήματος για την εφαρμογή της. Συνεπώς η μεθοδολογία αυτή μπορεί να χαρακτηριστεί ως γενικευμένη, υπό την έννοια ότι μπορεί να εφαρμοστεί σε κάθε πρόβλημα δυναμικής βελτιστοποίησης σύνθεσης, σχεδιασμού και λειτουργίας.Τέλος, η προσαρμοστικότητα και εφαρμοσιμότητα της προτεινόμενης μεθοδολογίας αναδεικνύονται με την επίλυση πλήθους ρεαλιστικών αριθμητικών παραδειγμάτων. Σε κάθε παράδειγμα μελετάται η επίδραση συγκεκριμένων τεχνικών και οικονομικών παραμέτρων πάνω στη βέλτιστη λύση μέσω κατάλληλης παραμετρικής μελέτης. Τα αποτελέσματα παρέχουν ενδιαφέρουσες ιδέες σχετικά με τη βέλτιστη σύνθεση,τον σχεδιασμό και τη λειτουργία των ενεργειακών συστημάτων πλοίων και αποδεικνύουν την καταλληλότητα της προτεινόμενης διαδικασίας μοντελοποίησης και βελτιστοποίησης για αυτό το είδος των προβλημάτων.

Developing an Integrated Energy System Interface for Electricity-Hydrogen Hybrid Nuclear Operations

2020 ◽  
Vol 64 (1) ◽  
pp. 92-96
Author(s):  
Thomas A. Ulrich ◽  
Roger Lew ◽  
Ronald L. Boring ◽  
Torrey Mortenson ◽  
Jooyoung Park ◽  
...  
Keyword(s):  
Human Factors ◽  
Electricity Markets ◽  
Nuclear Power ◽  
Power Plants ◽  
Energy Systems ◽  
Energy System ◽  
Human Factors Engineering ◽  
Engineering Project ◽  
Early Integration ◽  
Integrated Energy Systems

Nuclear power plants are looking towards integrated energy systems to address the challenges faced by increasing competition from renewable energy and cheap natural gas in wholesale electricity markets. Electricity-hydrogen hybrid operations is one potential technology being explored. As part of this investigation a human factors team was integrated into the overall engineering project to develop a human system interface (HSI) for a novel system to extract steam for a coupled hydrogen production process. This paper presents the process used to perform the nuclear specific human factors engineering required to develop the HSI for this novel and unprecedented system. Furthermore, the early integration of the human factors team and the meaningful improvements to the engineering of the system itself in addition to the successful development of the HSI for this particular application are described. Lastly, the HSI developed is presented to demonstrate the culmination of the process and disseminate a potential HSI design for electricity-hydrogen hybrid operations that may be useful for others exploring similar integrated energy systems concepts.

scholarly journals Modelling the Future of the Baltic Energy Systems: A Green Scenario

2021 ◽  
Vol 58 (3) ◽  
pp. 47-65
Author(s):  
L. Petrichenko ◽  
R. Petrichenko ◽  
A. Sauhats ◽  
K. Baltputnis ◽  
Z. Broka
Keyword(s):  
Renewable Energy ◽  
Power Plant ◽  
Power Systems ◽  
Power Plants ◽  
Optimization Problems ◽  
Renewable Energy Sources ◽  
Energy Systems ◽  
Energy Sources ◽  
Baltic States ◽  
The Baltic

Abstract The electricity sector in Europe and in the world is undergoing rapid and profound changes. There is a sharp increase in the capacity of renewable energy sources, coal and nuclear power plants are being closed and new technologies are being introduced. Especially rapid changes are taking place in the energy systems of the Baltic States. Under these conditions, there is an emerging need for new planning tools particularly for the analysis of the power system properties in a long-term perspective. The main contribution of this article lies in the formulation and solution of optimization problems that arise when planning the development of power systems in the Baltic States. To solve this problem, it is necessary to use models of various power plants and make a number of assumptions, the justification of which requires the following actions: to briefly review the current situation of the production and demand of energy in the Baltic power systems; to conduct an overview of the Baltic interconnections and their development; to make forecasts of energy prices, water inflow, energy production and demand; to set and solve the problems of optimization of power plant operation modes; to demonstrate the possibility and limitations of the developed tools on the basis of real-life and forecast data. In this paper, a case study is performed using the main components of the overall modelling framework being developed. It focuses on the Baltic power systems in 2050 under the conditions of significant expansion in the installed capacity of renewable energy sources (RESs) and diminished fossil fuel power plant activity. The resulting electricity generation mix and trade balance with neighbouring countries is assessed, showing that even with significant RES expansion, the Baltic countries remain net importers and because of the intermittency of RESs, there are hours within the year when the demand cannot be met.

Dynamic Optimization of Chemical Processes Based on Modified Sailfish Optimizer Combined with an Equal Division Method

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1806
Author(s):  
Yuedong Zhang ◽  
Yuanbin Mo
Keyword(s):  
Dynamic Optimization ◽  
Production Efficiency ◽  
Chemical Engineering ◽  
Optimization Problems ◽  
Optimal Solution ◽  
Population Diversity ◽  
Equal Division ◽  
Dynamic Optimization Problems ◽  
Increase Production Efficiency ◽  
Chaotic Mapping

The optimal solution of the chemical dynamic optimization problem is the basis of automatic control operation in the chemical process, which can reduce energy consumption, increase production efficiency, and maximize economic benefit. In this paper, a modified sailfish optimizer (MSFO) combined with an equal division method is proposed for solving chemical dynamic optimization problems. Based on the basic sailfish optimizer, firstly, the tent chaotic mapping strategy is introduced to disturb the initialization of sailfish and sardine populations to avoid the loss of population diversity. Secondly, an adaptive linear reduction strategy of attack parameters is proposed to enhance the exploration and exploitation ability of sailfish. Thirdly, the updating formula of sardine position is modified, and the global optimal solution is used to attract all sardine positions, which can avoid the premature phenomenon of the algorithm. Eventually, the MSFO is applied to solve six classical optimization cases of chemical engineering to evaluate its feasibility. The experimental results are analyzed and compared with other optimization methods to prove the superiority of the MSFO in solving chemical dynamic optimization problems.

scholarly journals Conventional Hydraulic Circuits in an Analysis of Environmental Issues

2018 ◽  
Vol 69 ◽  
pp. 02003
Author(s):  
Boris M. Kaganovich ◽  
Valery A. Stennikov ◽  
Maxim S. Zarodnyuk ◽  
Sergey V. Yakshin
Keyword(s):  
Power Plants ◽  
Energy Systems ◽  
Anthropogenic Pollution ◽  
Integrated System ◽  
Irreversible Processes ◽  
Integrated Energy Systems ◽  
Wind Power Plants ◽  
Economic Nature ◽  
The Impact ◽  
Hydraulic Circuits

The paper addresses the problems of conventional circuit modeling in an analysis of anthropogenic pollution of nature. A joint use of two types of models is proposed: 1) a model of conventional hydraulic circuits and 2) a model of extreme intermediate states developed by Melentiev Energy Systems Institute. The first model is used to calculate the distribution of pollutants in the atmosphere and their precipitation. The second model is intended for an analysis of the formation of pollutants and their transformations in branches as a result of chemical reactions and phase transitions. The analysis is based on the propositions of classical equilibrium thermodynamics. The applicability of the thermodynamic equilibrium and extremality principles and one-dimensional circuit models in the study of both reversible and irreversible processes are substantiated. Specific problems are analyzed. These are the determination of the yield of harmful substances in fuel combustion and processing, the distribution of pollutants in the atmosphere of large regions, the impact of hydro and wind power plants on the formation of harmful solutions in the air. The possibility of using a conventional graph (a thermodynamic tree) proposed by A.N. Gorban to analyze fuel technologies is demonstrated. The statement of the problem related to the assessment of the environmental compatibility of integrated energy systems is presented. The admissibility of the representation of the optimal distribution of flows in the integrated system as a sum of optimal distributions in its subsystems that differ from one another in physical-technical and economic nature is explained.

Genetic Algorithms with Immigrants Scheme for Dynamic Optimization Problems

2013 ◽  
Vol 333-335 ◽  
pp. 1379-1383
Author(s):  
Yan Wu ◽  
Xiao Xiong Liu
Keyword(s):  
Genetic Algorithms ◽  
Dynamic Optimization ◽  
Optimization Problems ◽  
Main Idea ◽  
Optimal Solution ◽  
Search Space ◽  
Dynamic Environments ◽  
Dynamic Optimization Problems ◽  
New Space ◽  
Over Time

In dynamic environments, it is difficult to track a changing optimal solution over time. Over the years, many approaches have been proposed to solve the problem with genetic algorithms. In this paper a new space-based immigrant scheme for genetic algorithms is proposed to solve dynamic optimization problems. In this scheme, the search space is divided into two subspaces using the elite of the previous generation and the range of variables. Then the immigrants are generated from both the subspaces and inserted into current population. The main idea of the approach is to increase the diversity more evenly and dispersed. Finally an experimental study on dynamic sphere function was carried out to compare the performance of several genetic algorithms. The experimental results show that the proposed algorithm is effective for the function with moving optimum and can adapt the dynamic environments rapidly.

scholarly journals Improved Seagull Optimization Algorithm Combined with an Unequal Division Method to Solve Dynamic Optimization Problems

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1037
Author(s):  
Le Xu ◽  
Yuanbin Mo ◽  
Yanyue Lu ◽  
Jiang Li
Keyword(s):  
Dynamic Optimization ◽  
Optimization Algorithm ◽  
Optimization Problems ◽  
Optimal Solution ◽  
Difficult Problem ◽  
Attack Behavior ◽  
Dynamic Optimization Problems ◽  
Group Approach ◽  
Unequal Division ◽  
Fitness Value

The numerical solution of the dynamic optimization problem is often sought for chemical processes, but the discretization of control variables is a difficult problem. Firstly, based on the analysis of the seagull optimization algorithm, this paper introduces the cognitive part in the process of a seagull’s attack behavior to make the group approach the best position. Secondly, the algorithm adds the mechanism of natural selection, where the fitness value is used to sort the population, and the best half is used to replace the worst half, so as to find out the optimal solution. Finally, the improved seagull optimization algorithm (ISOA) is combined with the unequal division method to solve dynamic optimization problems. The feasibility of the method is verified by three practical examples of dynamic optimization in chemical industry.

scholarly journals Belarus Power Engineering System Modeling Taking into Account the Nuclear Power Plant Commissioning

2021 ◽  
Vol 64 (1) ◽  
pp. 5-14
Author(s):  
A. A. Mikhalevic ◽  
U. A. Rak
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Energy Systems ◽  
Operating Conditions ◽  
Power Engineering ◽  
Power Balance ◽  
Engineering System ◽  
Large Share ◽  
Load Duration

The article presents the analysis of the specific features of modeling the operation of energy systems with a large share of nuclear power plants (NPP). The study of operating conditions and characteristics of different power units showed that a power engineering system with a large share of NPP and CHPP requires more detailed modeling of operating modes of generating equipment. Besides, with an increase in the share of installations using renewable energy sources, these requirements are becoming tougher. A review of the literature revealed that most often the curve of the load duration and its distribution between blocks are used for modeling energy systems. However, since this method does not reflect a chronological sequence, it can only be used if there are no difficulties with ensuring power balance. Along with this, when the share of CHP and nuclear power plants is high, to maintain a balance of power one must know the parameters and a set of powered equipment not only currently but, also, in the previous period. But this is impossible if a curve of load duration is used. For modeling, it is necessary to use an hourly load curve and to calculate the state of the energy system for each subsequent hour in chronological order. In the course of a comparative analysis of available computer programs, it was not possible to identify a suitable model among the existing ones. The article presents a mathematical model developed by the authors, which makes us possible to simulate the operation of a power engineering system with a large share of NPP and CHPP while maintaining the power balance for each hour of the forecast period. Verification of the proposed model showed good accuracy of the methods used.

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