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optimizing-the-operating-conditions
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An imperialist competitive algorithm approach for multi-objective optimization of direct coupling photovoltaic-electrolyzer systems
, Article International Journal of Hydrogen Energy ; Vol. 39, Issue 33 , 11 November , 2014 , pp. 18743-18757 ; ISSN: 03603199 ; Sayedin, F ; Khavas, S. S
Abstract
In the context of sustainable clean hydrogen production pathways, photovoltaic-electrolyzer systems are one of the most promising alternatives for acquiring hydrogen from renewable energy sources. In fact, determining the optimal set of design and operating variables are always a key issue while coupling directly renewable electricity sources to PEM electrolyzers. Few previous studies have attempted to find the optimal size and operational condition of directly coupled photovoltaic-electrolyzer (PV/El) systems in order to maximize the hydrogen production or to minimize energy transfer loss between photovoltaic devices and the electrolyzer. Nevertheless an easy and efficient approach still...
Two strategies for multi-objective optimisation of solid oxide fuel cell stacks
, Article International Journal of Sustainable Energy ; Vol. 33, issue. 4 , 2014 , p. 854-868 ; Behzadi Forough, A ; Sharif University of Technology
Abstract
This paper focuses on multi-objective optimisation (MOO) to optimise the planar solid oxide fuel cell (SOFC) stacks performance using a genetic algorithm. MOO problem does not have a single solution, but a complete Pareto curve, which involves the optional representation of possible compromise solutions. Here, two pairs of different objectives are considered as distinguished strategies. Optimisation of the first strategy predicts a maximum power output of 108.33 kW at a breakeven per-unit energy cost of 0.51 $/kWh and minimum breakeven per-unit energy cost of 0.30 $/kWh at a power of 42.18 kW. In the second strategy, maximum efficiency of 63.93%at a breakeven per-unit energy cost of 0.42...
A new approach to optimize the operating conditions of a polymer electrolyte membrane fuel cell based on degradation mechanisms
, Article Energy Systems ; Volume 4, Issue 3 , 2013 , Pages 219-237 ; 18683967 (ISSN) ; Parhizgar, T ; Sharif University of Technology
2013
Abstract
Performance degradation remains as one of the primary limitations for practical applications of proton exchange membrane (PEM) fuel cells. The performance of a PEM fuel cell stack is affected by many internal and external factors, such as fuel cell design and assembly, degradation of materials, operational conditions, and impurities or contaminants. Performance degradation is unavoidable, but the degradation rate can be minimized through a comprehensive understanding of degradation and failure mechanisms. In present work, a single PEM fuel cell for stationary applications is investigated. Membrane and catalyst layers (anode and cathode electrodes) are considered as critical components that...
An approach to optimize correlated multiple responses using principal component analysis and desirability function
, Article International Journal of Advanced Manufacturing Technology ; Volume 62, Issue 5-8 , September , 2012 , Pages 835-846 ; 02683768 (ISSN) ; Kazemzadeh, R. B ; Niaki, S. T. A ; Sharif University of Technology
Springer
2012
Abstract
While researchers have developed several approaches to attain design variable settings that simultaneously optimize multiple-quality characteristics, the multi-response optimization has become a common practice in complicated manufacturing processes. Most of these research works assume independency of responses where their variances are constant over the experimental space. However, there are many manufacturing processes in practice where the quality characteristics under consideration are correlated. In this study, an efficient approach based on principal component analysis and a conventional desirability function is proposed to optimize correlated multiple responses. This approach not only...
Thermoeconomic approach for optimal design of gas turbine heat recovery steam generator
, Article Proceedings of the 26th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2013 ; July , 2013 ; Parhizgar, T ; Ghorbanian, K ; Sharif University of Technology
China International Conference Center for Science and Technology
2013
Abstract
In the present study a comprehensive thermoeconomic modelling of a heat recovery steam generator (HRSG) for a typical 4MW class gas turbine is performed. Usually, the thermoeconomic analyses involve a thermodynamic model of the HRSG and an economic model dedicated to assess the cost. In this study, different configurations of single and dual pressure level HRSGs are optimized and afterward compared to find the economical design. For these configurations thermodynamic model calculates the performance and the energy balance of systems at the optimal operating conditions which are derived from optimization model, and economic model estimates total cost per unit of produced energy. Finally,...
Optimization of industrial CSTR for vinyl acetate polymerization using novel shuffled frog leaping based hybrid algorithms and dynamic modeling
, Article Computers and Chemical Engineering ; Volume 35, Issue 11 , November , 2011 , Pages 2351-2365 ; 00981354 (ISSN) ; Shojaei, A ; Sharif University of Technology
2011
Abstract
Industrial scale continuous stirred tank reactor (CSTR) for production and grade transitions of poly vinyl acetate (PVAc) at the different reactor sizes was investigated. Such reactor is known to show oscillatory behavior and to have periodic limit points, particularly at high molecular weights. Four efficient novel hybrid optimization methods which use variable population size genetic algorithm (VPGA), bacterial optimization algorithm (BO) and shuffled frog leaping method (SFL) were introduced for this kind of reactors. These algorithms can reliably find dynamically stable points with desired conditions for PVAc production. The dynamic modeling combined with the new hybrid optimization...
Effects of different operating parameters on the particle size of silver chloride nanoparticles prepared in a spinning disk reactor
, Article Applied Physics A: Materials Science and Processing ; Volume 120, Issue 1 , July , 2015 , Pages 105-113 ; 09478396 (ISSN) ; Davarpanah, M ; Ahmadpour, A ; Sharif University of Technology
Springer Verlag
2015
Abstract
The aim of this research was to present an experimental method for large-scale production of silver chloride nanoparticles using spinning disk reactor. Silver nitrate and sodium chloride were used as the reactants, and the protecting agent was gelatin. The experiments were carried out in a continuous mode by injecting the reactants onto the surface of the spinning disk, where a chemical precipitation reaction took place to form AgCl particles. The effects of various operating variables, including supersaturation, disk rotational speed, reactants flow rate, disk diameter, and excess ions, on the particle size of products were investigated. In addition, the AgCl nanoparticles were...
Second law analysis of an infinitely segmented magnetohydrodynamic generator
, Article Journal of Magnetism and Magnetic Materials ; Volume 426 , 2017 , Pages 294-301 ; 03048853 (ISSN) ; Saidi, M. H ; Najafi, M ; Sharif University of Technology
Elsevier B.V
2017
Abstract
The performance of an infinitely segmented magnetohydrodynamic generator is analyzed using the second law of thermodynamics entropy generation criterion. The exact analytical solution of the velocity and temperature fields are provided by applying the modified Hartmann flow model, taking into account the occurrence of the Hall effect in the considered generator. Contributions of heat transfer, fluid friction, and ohmic dissipation to the destruction of useful available work are found, and the nature of irreversibilities in the considered generator is determined. In addition, the electrical isotropic efficiency scheme is used to evaluate the generator performance. Finally, the implication of...
Aging based optimal scheduling framework for power plants using equivalent operating hour approach
, Article Applied Energy ; Volume 205 , 2017 , Pages 1345-1363 ; 03062619 (ISSN) ; Mosleh, A ; Roshandel, R ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
In this paper a scheduling optimization framework is developed to enhance power plants operational decision making process. The proposed framework optimizes plant schedule including operating conditions and maintenance intervals simultaneously and on an hourly basis. In a long term operation plant performance deteriorates due to components aging. This study employs equivalent operating hour (EOH) approach to describe components aging impact on the plant performance deterioration and consequently plant long term profit. Modeling of components aging increases system simulation accuracy in long term operation and the optimum decision variables would be more reliable and realistic. Validity and...
Degradation based operational optimization model to improve the productivity of energy systems, case study: Solid oxide fuel cell stacks
, Article Energy Conversion and Management ; Volume 158 , 2018 , Pages 81-91 ; 01968904 (ISSN) ; Hafeznezami, S ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In the present study a comprehensive thermodynamic model and degradation based optimization framework for energy management of anode supported solid oxide fuel cell (SOFC) stacks are carried out. The optimization framework determines optimum operating conditions to maximize system productivity (energy generation over system lifetime) considering degradation mechanisms. The main degradation mechanisms in anode supported SOFCs are nickel coarsening and oxidation. In this study, the optimum operating conditions regarding these degradation mechanisms to achieve maximum productivity at different target lifetimes are derived. The results show that target lifetime has a significant impact on system...
Joint distributed generation and active distribution network expansion planning considering active management of network
, Article 27th Iranian Conference on Electrical Engineering, ICEE 2019, 30 April 2019 through 2 May 2019 ; 2019 , Pages 702-708 ; 9781728115085 (ISBN) ; Fotuhi Firuzabad, M ; Moeini Aghtaie, M ; Pourghaderia, N ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Joint multistage expansion planning of active distribution network (ADN) is well investigated in this paper. This expansion model considers the effects of optimal operating conditions in the planning studies. In the proposed model, for each planning time stage, several operating scenarios are defined based on operational status of the network. The utilization of distributed energy resources (DERs) around the network is determined for each operating scenario through active management of these resources. In the planning level, investment in distribution network assets including feeders, substations, and distributed generations (DGs) incorporating conventional gas turbines and renewable wind...
Application of particle swarm optimization and genetic algorithm for optimization of a southern Iranian oilfield
, Article Journal of Petroleum Exploration and Production ; Volume 11, Issue 4 , 2021 , Pages 1781-1796 ; 21900558 (ISSN) ; Dehghan, A ; Yousefzadeh, R ; Sharif University of Technology
Springer Science and Business Media B.V
2021
Abstract
Optimization of the placement and operational conditions of oil wells plays an important role in the development of the oilfields. Several automatic optimization algorithms have been used by different authors in recent years. However, different optimizers give different results depending on the nature of the problem. In the current study, a comparison between the genetic algorithm and particle swarm optimization algorithms was made to optimize the operational conditions of the injection and production wells and also to optimize the location of the injection wells in a southern Iranian oilfield. The current study was carried out with the principal purpose of evaluating and comparing the...
Performance optimization of a new flash-binary geothermal cycle for power/hydrogen production with zeotropic fluid
, Article Journal of Thermal Analysis and Calorimetry ; Volume 145, Issue 3 , 2021 , Pages 1633-1650 ; 13886150 (ISSN) ; Hosseini Dehshiri, S ; Mostafaeipour, A ; Issakhov, A ; Techato, K ; Arockia Dhanraj, J ; Sharif University of Technology
Springer Science and Business Media B.V
2021
Abstract
In this study, the performance of a system consisting of an organic Rankine cycle (ORC) for generating power and an electrolyzer for producing hydrogen with a zeotropic mixture as working fluid to recover waste heat in a geothermal flash-binary cycle is investigated from energy and exergy point of view. The study also investigates the effect of using zeotropic mixtures with different compositions as the ORC's working fluid rather than pure fluids. Using the particle swarm optimization (PSO) algorithm, the optimization is performed to maximize the power production of the entire system. The results show that using the combination of pentane with other pure fluids as working fluid led to...
Combined UV-C/H2O2-VUV processes for the treatment of an actual slaughterhouse wastewater
, Article Journal of Environmental Science and Health - Part B Pesticides, Food Contaminants, and Agricultural Wastes ; Volume 52, Issue 5 , 2017 , Pages 314-325 ; 03601234 (ISSN) ; Bustillo Lecompte, C. F ; Mehrvar, M ; Abdekhodaie, M. J ; Sharif University of Technology
Taylor and Francis Inc
2017
Abstract
In this study, a three-factor, three-level Box-Behnken design with response surface methodology were used to maximize the TOC removal and minimize the H2O2 residual in the effluent of the combined UV-C/H2O2-VUV system for the treatment of an actual slaughterhouse wastewater (SWW) collected from one of the meat processing plants in Ontario, Canada. The irradiation time and the initial concentrations of total organic carbon (TOCo) and hydrogen peroxide (H2O2o) were the three predictors, as independent variables, studied in the design of experiments. The multiple response approach was used to obtain desirability response surfaces at the optimum factor settings. Subsequently, the optimum...
Light olefin production on the Co-Ni catalyst: Calcination conditions, and modeling and optimization of the process conditions by a statistical method
, Article New Journal of Chemistry ; Volume 44, Issue 18 , 2020 , Pages 7467-7483 ; Akbari, M ; Mirzaei, N ; Abdouss, M ; Sharif University of Technology
Royal Society of Chemistry
2020
Abstract
The present work is comprised of two main parts. In part 1 the Co-Ni/γ-Al2O3 catalyst was prepared using a sol-gel procedure. Then the effect of calcination variables including the calcination temperature and time on the catalytic performance for production of light olefins was investigated and optimized. The obtained results have shown that the catalyst which was calcined at 550 °C for 6 h has revealed the better catalytic performance for production of light olefins. In part 2 the effect of process conditions including the reaction temperature, H2/CO feed ratio and total reaction pressure on the catalytic performance (CO conversion%, (C2-C4) selectivity% and C5+ selectivity%) was...