Documents disponibles écrits par cet auteur

Efficient design under uncertainty of renewable power generation systems using partitioning and regression in the course of optimization / Athanasios I. Papadopoulos in Industrial & engineering chemistry research, Vol. 51 N° 39 (Octobre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12862-12876 Titre : Efficient design under uncertainty of renewable power generation systems using partitioning and regression in the course of optimization Type de document : texte imprimé Auteurs : Athanasios I. Papadopoulos, Auteur ; Garyfallos Giannakoudis, Auteur ; Panos Seferlis, Auteur Année de publication : 2012 Article en page(s) : pp. 12862-12876 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Optimization  Phase  partition  Uncertainty  Design Résumé : Renewable power generation systems are significantly affected by uncertainty due to intense variability often observed in energy sources. Uncertainty should be considered during design to enable optimum performance within constantly changing conditions. However, the resulting computational complexity and effort is high, especially in view of flowsheets integrating multiple subsystems. To address this challenge, the presented work proposes the partitioning of the space representing uncertain realizations to facilitate the development and continuous update of a surrogate model in the course of optimization. A wide exploration of this strategy reveals and addresses important issues in the implementation of the partitioning and model regression layers. Formal statistical associations are examined regarding the beneficial implications of partitioning to computational efficiency and surrogate model development. The proposed strategy is presented as part of a Simulated Annealing algorithm. This is tested in terms of computational efficiency and solution robustness against an adaptation of Stochastic Annealing, which addresses computational intensity through a different approach while depending entirely on a full system model Results are illustrated through numerical examples and case studies on a stand-alone, hybrid system using renewable energy sources for power generation and storage. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419243 [article] Efficient design under uncertainty of renewable power generation systems using partitioning and regression in the course of optimization [texte imprimé] / Athanasios I. Papadopoulos, Auteur ; Garyfallos Giannakoudis, Auteur ; Panos Seferlis, Auteur . - 2012 . - pp. 12862-12876. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12862-12876 Mots-clés : Optimization  Phase  partition  Uncertainty  Design Résumé : Renewable power generation systems are significantly affected by uncertainty due to intense variability often observed in energy sources. Uncertainty should be considered during design to enable optimum performance within constantly changing conditions. However, the resulting computational complexity and effort is high, especially in view of flowsheets integrating multiple subsystems. To address this challenge, the presented work proposes the partitioning of the space representing uncertain realizations to facilitate the development and continuous update of a surrogate model in the course of optimization. A wide exploration of this strategy reveals and addresses important issues in the implementation of the partitioning and model regression layers. Formal statistical associations are examined regarding the beneficial implications of partitioning to computational efficiency and surrogate model development. The proposed strategy is presented as part of a Simulated Annealing algorithm. This is tested in terms of computational efficiency and solution robustness against an adaptation of Stochastic Annealing, which addresses computational intensity through a different approach while depending entirely on a full system model Results are illustrated through numerical examples and case studies on a stand-alone, hybrid system using renewable energy sources for power generation and storage. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419243

Optimal design of staged three-phase reactive distillation columns using nonequilibrium and orthogonal collocation models / Theodoros Damartzis in Industrial & engineering chemistry research, Vol. 49 N° 7 (Avril 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 7 (Avril 2010) . - pp. 3275–3285 Titre : Optimal design of staged three-phase reactive distillation columns using nonequilibrium and orthogonal collocation models Type de document : texte imprimé Auteurs : Theodoros Damartzis, Auteur ; Panos Seferlis, Auteur Année de publication : 2010 Article en page(s) : pp. 3275–3285 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Design  Staged  Distillation  Columns  Nonequilibrium  Orthogonal Résumé : Reactive distillation with potential liquid-phase split and subsequent formation of a third phase is a highly complex process system nevertheless quite common in the production of useful solvents and biofuels through esterification. The optimal design of such process systems requires the development and solution of reliable and accurate process models that lead to a computationally demanding mathematical problem. In this work, a nonequilibrium (NEQ) model coupled with the orthogonal collocation on finite elements (OCFE) technique is developed for the simulation and optimal design of three-phase reactive distillation systems. The resulting NEQ/OCFE model combines the predictive accuracy of the NEQ model as well as the model reduction and approximation capabilities of the OCFE formulation. Therefore, an accurate but compact in size and thus easier to solve model that accounts for all the physical phenomena, the interactions among the multiple phases, and the occurring chemical reactions becomes available. The NEQ/OCFE model is enriched with an accurate prediction procedure for the identification and tracking of the phase transition boundaries (point of transition for a single liquid phase to two liquid-phase regimes and vice versa) inside the column for varying operating conditions. The model is validated using experimental results and utilized in the optimal design and the dynamic simulation of a staged reactive distillation column for the production of butyl acetate via the esterification reaction of butanol with acetic acid. The optimal column configuration defined by the number of stages in each column section, the feed strategy (single feed or multiple feed points), the location of the feed stages, and the operating conditions are calculated through a rigorous design optimization procedure for tight production purity specifications. At optimal conditions the specific column appears to have both two- and three-phase regions that are separated by the feed stage. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901260b [article] Optimal design of staged three-phase reactive distillation columns using nonequilibrium and orthogonal collocation models [texte imprimé] / Theodoros Damartzis, Auteur ; Panos Seferlis, Auteur . - 2010 . - pp. 3275–3285. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 7 (Avril 2010) . - pp. 3275–3285 Mots-clés : Design  Staged  Distillation  Columns  Nonequilibrium  Orthogonal Résumé : Reactive distillation with potential liquid-phase split and subsequent formation of a third phase is a highly complex process system nevertheless quite common in the production of useful solvents and biofuels through esterification. The optimal design of such process systems requires the development and solution of reliable and accurate process models that lead to a computationally demanding mathematical problem. In this work, a nonequilibrium (NEQ) model coupled with the orthogonal collocation on finite elements (OCFE) technique is developed for the simulation and optimal design of three-phase reactive distillation systems. The resulting NEQ/OCFE model combines the predictive accuracy of the NEQ model as well as the model reduction and approximation capabilities of the OCFE formulation. Therefore, an accurate but compact in size and thus easier to solve model that accounts for all the physical phenomena, the interactions among the multiple phases, and the occurring chemical reactions becomes available. The NEQ/OCFE model is enriched with an accurate prediction procedure for the identification and tracking of the phase transition boundaries (point of transition for a single liquid phase to two liquid-phase regimes and vice versa) inside the column for varying operating conditions. The model is validated using experimental results and utilized in the optimal design and the dynamic simulation of a staged reactive distillation column for the production of butyl acetate via the esterification reaction of butanol with acetic acid. The optimal column configuration defined by the number of stages in each column section, the feed strategy (single feed or multiple feed points), the location of the feed stages, and the operating conditions are calculated through a rigorous design optimization procedure for tight production purity specifications. At optimal conditions the specific column appears to have both two- and three-phase regions that are separated by the feed stage. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901260b