Search for: proton-exchange-membrane-fuel-cells--pemfc
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    Artificial neural network modeling of Pt/C cathode degradation in pem fuel cells

    , Article Journal of Electronic Materials ; Volume 45, Issue 8 , 2016 , Pages 3822-3834 ; 03615235 (ISSN) Maleki, E ; Maleki, N ; Sharif University of Technology
    Springer New York LLC  2016
    Use of computational modeling with a few experiments is considered useful to obtain the best possible result for a final product, without performing expensive and time-consuming experiments. Proton exchange membrane fuel cells (PEMFCs) can produce clean electricity, but still require further study. An oxygen reduction reaction (ORR) takes place at the cathode, and carbon-supported platinum (Pt/C) is commonly used as an electrocatalyst. The harsh conditions during PEMFC operation result in Pt/C degradation. Observation of changes in the Pt/C layer under operating conditions provides a tool to study the lifetime of PEMFCs and overcome durability issues. Recently, artificial neural networks... 

    Optimal PV-FC hybrid system operation considering reliability

    , Article International Journal of Electrical Power and Energy Systems ; Vol. 60, issue , September , 2014 , p. 325-333 Rajabi-Ghahnavieh, A ; Nowdeh, S. A ; Sharif University of Technology
    This paper presents an approach for optimal operation of a grid-connected hybrid system to maximize the system expected generated energy while maximizing the electricity sale revenue. The hybrid system consists of a photovoltaic (PV) module, an electrolyser (EL), hydrogen storage tank (HS) and a proton exchange membrane (PEM) fuel cell (FC). The generated energy is sold to the distribution grid. During the grid interruptions, the hybrid system output is used as an emergency supply to serve the local load, hence increasing the supply reliability. The proposed approach splits the whole problem in two sub problems: revenue maximizing problem (RMP) and expected generation maximizing problem... 

    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) Roshandel, R ; Parhizgar, T ; Sharif University of Technology
    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... 

    Modeling water content distribution in the polymer electrolyte membrane of pem fuel cell

    , Article ASME 2011 9th International Conference on Fuel Cell Science, Engineering and Technology. Collocated with ASME 2011 5th International Conference on Energy Sustainability, FUELCELL 2011, 7 August 2011 through 10 August 2011, Washington, DC ; 2011 , Pages 851-858 ; 9780791854693 (ISBN) Tavakoli, B. A ; Roshandel, R ; Sharif University of Technology
    Models play an important role in fuel cell design and development. One of the critical problems to overcome in the proton exchange membrane (PEM) fuel cells is the water management. In this work a steady state, two dimensional, isothermal model in a single PEM fuel cell using individual computational fluid dynamics code was presented. Special attention was devoted to the water transport through the membrane which is assumed to be combined effect of diffusion, electro osmotic drag and convection. The effect of current density variation distribution on the Water content (λ) in membrane/electrode assembly (MEA) was determined. After that detailed distribution of oxygen concentration, water... 

    Effect of water-methanol content on the structure of Nafion in the sandwich model and solvent dynamics in nano-channels; A molecular dynamics study

    , Article Molecular Physics ; Volume 109, Issue 5 , Mar , 2011 , Pages 709-724 ; 00268976 (ISSN) Abroshan, H ; Akbarzadeh, H ; Taherkhani, F ; Parsafar, G ; Sharif University of Technology
    Continuing an ongoing study, molecular dynamics (MD) simulations were performed to investigate the effects of methanol concentration on Nafion morphology, such as the size of solvent cluster, solvent location, and polymer structure via the sandwich model. Our survey shows that high methanol concentrations resulted in increment of solvent cluster size in Nafion membrane. The sulfonic acid clusters also befall much in order as subsequent layers of such ionic clusters are formed. The number of neighbouring hydronium ions around a sulfur atom is independent of methanol concentration, but the first shell of hydronium and water around sulfonic acid clusters is broader. Although methanol would... 

    Properties of Nafion Under Uniaxial Loading at Different Temperatures: A Molecular Dynamics Study

    , Article Polymer - Plastics Technology and Engineering ; Volume 54, Issue 8 , 2015 , Pages 806-813 ; 03602559 (ISSN) Ozmaian, M ; Naghdabadi, R ; Sharif University of Technology
    Taylor and Francis Inc  2015
    Nafion membrane encounters many different thermal conditions and mechanical loadings because of its wide range of applications as a proton exchange membrane (PEM). Molecular dynamics simulation of hydrated Nafion at different temperatures is carried out to investigate the alteration of the physical properties of Nafion under uniaxial loading over a wide range of temperatures. According to the simulation results, increase of the temperature reduces the yield stress. The results also show that the polymer chains ordering increases the glass transition temperature and enhances the self-diffusion coefficient of water in hydrated Nafion. Comparisons show that the elastic modulus and viscosity... 

    Evaluating one of renewable electricity generation technologies: PEM fuel cells

    , Article EPEC 2010 - IEEE Electrical Power and Energy Conference: "Sustainable Energy for an Intelligent Grid", 25 August 2010 through 27 August 2010, Halifax, NS ; 2010 ; 9781424481880 (ISBN) Hoseinnia, S ; Sadeghzadeh, S. M ; Fathi, A. H ; Nasiri, M ; Sharif University of Technology
    Proton Exchange Membrane (PEM) Fuel Cells are attracting most of the electricity consumers because of high efficiency, zero carbon emissions and high reliability. There are many parameters influencing on this power source's operation. A model of PEM fuel cell will be presented and the sensitivity of the fuel cell's parameters will be analyzed. Multi Parameters Sensitivity Analysis is used next to examine the relative importance of the influential parameters on the PEM fuel cell operation  

    A predictive control based on neural network for proton exchange membrane fuel cell

    , Article World Academy of Science, Engineering and Technology ; Volume 50 , 2011 , Pages 456-460 ; 2010376X (ISSN) Sedighizadeh, M ; Rezaei, M ; Najmi, V ; Sharif University of Technology
    The Proton Exchange Membrane Fuel Cell (PEMFC) control system has an important effect on operation of cell. Traditional controllers couldn't lead to acceptable responses because of time- change, long- hysteresis, uncertainty, strong- coupling and nonlinear characteristics of PEMFCs, so an intelligent or adaptive controller is needed. In this paper a neural network predictive controller have been designed to control the voltage of at the presence of fluctuations of temperature. The results of implementation of this designed NN Predictive controller on a dynamic electrochemical model of a small size 5 KW, PEM fuel cell have been simulated by MATLAB/SIMULINK  

    Integration of miniature heat pipes into a proton exchange membrane fuel cell for cooling applications

    , Article Heat Transfer Engineering ; Volume 38, Issue 18 , 2017 , Pages 1595-1605 ; 01457632 (ISSN) Shirzadi, N ; Roshandel, R ; Behshad Shafii, M ; Sharif University of Technology
    In proton exchange membrane fuel cell (PEMFC) operations, the electrochemical reactions produce a rise in temperature. A fuel cell stack therefore requires an effective cooling system for optimum performance. In this study, miniature heat pipes were applied for cooling in PEMFC. Three alternatives were considered in tests: free convection, forced convection cooling with air, and also water. An analytical model was developed to show the possibility of evoking heat from inside a fuel cell stack with different numbers of miniature heat pipes. An experiment setup was designed and then used for further analysis. The proposed experiment setup consisted of a simulated fuel cell that produced heat... 

    Fluid dynamics performance of bio -inspired flow channel design for bipolar plates in PEM fuel cells

    , Article 3rd European Fuel Cell Technology and Applications - Piero Lunghi Conference, EFC 2009, 15 December 2009 through 18 December 2009 ; 2009 , Pages 203-204 ; 9788882862114 (ISBN) Roshandel, R ; Karimi Moghaddam, G ; Barchiesi C ; Cigolotti V ; Chianella M ; McPhail S ; Lunghi P ; Sharif University of Technology
    ENEA  2009
    This study concentrates on the improvement in the performance of PEM fuel cells through optimization of the channel dimensions and patterns in the velocity and pressure fields in bipolar plates. For design and optimization purposes, a 2D numerical simulation of the flow distribution based on the Nervier-Stokes equations using individual computer code has been done. The outcome of the numerical simulations showed excellent agreement with the experimental results in previous works. Finally numerical simulation has been conducted to investigate the advantages of conventional patterns with inspiration from leaf flow pattern. It was found that both velocity and pressure fields are very uniform in... 

    Hydrophobic octadecylamine-functionalized graphene/TiO2 hybrid coating for corrosion protection of copper bipolar plates in simulated proton exchange membrane fuel cell environment

    , Article International Journal of Hydrogen Energy ; Volume 45, Issue 30 , 2020 , Pages 15380-15389 Sadeghian, Z ; Hadidi, M. R ; Salehzadeh, D ; Nemati, A ; Sharif University of Technology
    Elsevier Ltd  2020
    In the present work, G-TiO2 and G-ODA-TiO2 hybrids were prepared by concurrent surface functionalization and reducing of graphene oxide (GO) using octadecylamine (ODA). The G-TiO2 and G-ODA-TiO2 powders were deposited on the copper surface by electrophoretic deposition (EPD) technique. The wettability of coatings revealed the preferable hydrophobic characteristic of G-ODA-TiO2 compared to G-TiO2 and bare copper with water contact angles of 130°, 101°, and 87°, respectively. The anti-corrosion performance of specimens in a 0.5 M H2SO4 solution was appraised by the potentiodynamic polarization (Tafel analysis), which clearly showed that G-TiO2 and G-ODA-TiO2 coatings can act as a great barrier... 

    The effects of non-uniform distribution of catalyst loading on polymer electrolyte membrane fuel cell performance

    , Article International Journal of Hydrogen Energy ; Volume 32, Issue 17 , December , 2007 , Pages 4424-4437 ; 03603199 (ISSN) Roshandel, R ; Farhanieh, B ; Sharif University of Technology
    The catalyst layers are the most important part of the polymer electrolyte membrane (PEM) fuel cells, and the cell performance is highly related to its structure. The gas diffusion layers (GDLs) are also the essential components of the PEM fuel cell since the reactants should pass through these layers. Model prediction shows that electrical current in catalyst layer is non-uniform, influenced by the channel-land geometry. In addition, the compression effect of GDLs and water generation due to the electrochemical reaction may cause non-uniformity in porosity and, therefore, increases the non-uniformity in reactant concentration in GDL/catalyst layer interface. Simulation results suggest that... 

    Platinum nanoparticles with superacid-doped polyvinylpyrrolidone coated carbon nanotubes: Electrocatalyst for oxygen reduction reaction in high-temperature proton exchange membrane fuel cell

    , Article RSC Advances ; Volume 6, Issue 48 , 2016 , Pages 41937-41946 ; 20462069 (ISSN) Pourjafari Amyab, S ; Saievar Iranizad, E ; Bayat, A ; Sharif University of Technology
    Royal Society of Chemistry  2016
    In order to improve the catalytic activity and durability of proton-exchange-membrane-fuel-cells (PEMFCs), Nafion-free Pt-based catalyst using the superacid-doped polymer coated multiwall carbon nanotubes (MWCNTs) was investigated. The modification and nano polymerization of MWCNTs were developed by polyvinylpyrrolidone (PVP). The following observations were made in the presence of polymer: better dispersion of MWCNTs, higher thermal stability of MWCNT/PVP than that of pristine MWCNT up to 450 °C as tested by thermal gravimetric analysis (TGA), homogeneous distribution of Pt without agglomeration as observed by transmission electron microscope (TEM), and not too much difference in Pt loading... 

    Effects of microhydrophobic porous layer on water distribution in polymer electrolyte membrane fuel cells

    , Article Journal of Fuel Cell Science and Technology ; Vol. 11, Issue. 1 , 2014 ; ISSN: 1550-624X Ahmadi, F ; Roshandel, R ; Sharif University of Technology
    Performance of polymer electrolyte membrane fuel cells (PEMFC) at high current densities is limited to transport reactants and products. Furthermore, large amounts of water are generated and may be condensed due to the low temperature of the PEMFC. Development of a two-phase flow model is necessary in order to predict water flooding and its effects on the PEMFC performance. In this paper, a multiphase mixture model (M2) is used, accurately, to model two-phase transport in porous media of a PEMFC. The cathode side, which includes channel, gas diffusion layer (GDL), microporous layer (MPL), and catalyst layer (CL), is considered as the computational domain. A multidomain approach has been used... 

    Design and modeling of an integrated CHP system with solar hydrogen/methane fueled pem fuel cell for residential applications

    , Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) ; Vol. 6B , November , 2014 ; ISBN: 9780791849521 Amirian, H ; Sayedin, F ; Maroufmashat, A ; Sharif University of Technology
    This paper describes the designing and evaluation of an alternative energy system which consists of PEMFC, PV, PEM electrolyser, methane reformer and hydrogen tank. In order to find out the minimum capacity of the components, a system sizing model is developed in MATLAB based on meteorological and electrical demand data. Three scenarios are considered based on different combinations of solar energy and fossil fuel energy as energy resources. The heating energy produced by the fuel cell is recovered for supplying domestic hot water while the system would supply electrical energy. Results show that system sizing strongly depends on scenarios and unit cost of electricity decreases through the... 

    Directly coupled photovoltaic-electrolyzer system optimization using a novel ica methodology

    , Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) ; Vol. 6B, issue , 2014 Sayedin, F ; Maroufmashat, A ; Sattari, S ; Sharif University of Technology
    Hydrogen is considered to be the fuel of the future. It is a cleaner alternative to the fossil fuels we consume every day. Of all the different hydrogen production pathways that exist, producing the gas by utilizing the power generated by renewable energy sources has been a topic of interest for many researchers across the world. The following work focuses on minimizing the energy loss by optimizing the size and the operating conditions of an electrolyzer directly connected to a photovoltaic (PV) module at different irradiance. The hydrogen, in the proposed system, is produced using a proton exchange membrane (PEM) electrolyzer. A nonlinear method is considered, because of the complexity of... 

    Effects of catalyst loading gradient in catalyst layers on performance of polymer electrolyte membrane fuel cells

    , Article Renewable Energy ; Volume 50 , February , 2013 , Pages 921-931 ; 09601481 (ISSN) Roshandel, R ; Ahmadi, F ; Sharif University of Technology
    In this paper, numerical and analytical approaches are presented to evaluate the effect of catalyst loading gradient in the catalyst layer (CL) of a polymer electrolyte membrane (PEM) fuel cell. The model is developed based on agglomerate catalyst and accounts for reactant spices and charge (ion and electron) transport in the cathode side of a PEM fuel cell. The special variation of catalyst loading is considered in two direction, "across the layer" from membrane/CL interface to gas diffusion layer (GDL) and "in catalyst plane" under the channels and land areas in the channel direction. A fuel cell test stand is designed and built to facilitate experimental validation of the model. The... 

    Exergy, economic, and environmental analysis of a PEM fuel cell power system to meet electrical and thermal energy needs of residential buildings

    , Article Journal of Fuel Cell Science and Technology ; Volume 9, Issue 5 , 2012 ; 1550624X (ISSN) Ashari, G. R ; Ehyaei, M. A ; Mozafari, A ; Atabi, F ; Hajidavalloo, E ; Shalbaf, S ; Sharif University of Technology
    ASME  2012
    In this paper, a Polymer Electrolyte Membrane (PEM) fuel cell power system including burner, steam reformer, heat exchanger, and water heater has been considered. A PEM fuel cell system is designed to meet the electrical, domestic hot water, heating, and cooling loads of a residential building located in Tehran. Operating conditions of the system with consideration of the electricity cost has been studied. The cost includes social cost of the environmental pollutants (e.g. CO 2, CO and NO). The results show that the maximum energy needs of the building can be met by 12 fuel cell stacks with nominal capacity of 8.5 kW. Annual average electricity cost of thissystem is equal to 0.39 US$/kWh and... 

    Hydrogen generation optimization in a hybrid photovoltaic-electrolyzer using intelligent techniques

    , Article ASME 2012 10th International Conference on Fuel Cell Science, Engineering and Technology, FUELCELL 2012 Collocated with the ASME 2012 6th International Conference on Energy Sustainability, San Diego, CA, USA, 23 July 2012 through 26 July 2012 ; July , 2012 , Pages 19-24 ; 9780791844823 (ISBN) Maroufmashat, A ; Seyyedyn, F ; Roshandel, R ; Bouroshaki, M ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2012
    Hydrogen is a flexible energy carrier and storage medium and can be generated by electrolysis of water. In this research, hydrogen generation is maximized by optimizing the optimal sizing and operating condition of an electrolyzer directly connected to a PV module. The method presented here is based on Particle swarm optimization algorithm (PSO). The hydrogen, in this study, was produced using a proton exchange membrane (PEM) electrolyzer. The required power was supplied by a photovoltaic module rated at 80 watt. In order to optimize Hydrogen generation, the cell number of the electrolyser and its activity must be 9 and 3, respectively. As a result, it is possible to closely match the... 

    An innovative three dimensional numerical model for bipolar plates to enhance the efficiency of PEM fuel cells

    , Article ASME 2012 10th International Conference on Fuel Cell Science, Engineering and Technology Collocated with the ASME 2012 6th International Conference on Energy Sustainability, FUELCELL 2012, 23 July 2012 through 26 July 2012 ; July , 2012 , Pages 351-360 ; 9780791844823 (ISBN) Arbabi, F ; Roshandel, R ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2012
    The efficiency of proton exchange membrane (PEM) fuel cell is straightly correlated to the bipolar plate design and fluid channel arrangements. Higher produced energy can be attained by optimal design of type, size, or patterns of the channels. Previous researches showed that the bipolar plate channel design has a considerable effect on reactant distribution uniformity as well as humidity control in PEM fuel cells. This paper concentrates on enhancements in the fuel cell performance by optimization of bipolar plate design and channels configurations. A numerical model of flow distribution based on Navier-Stokes equations using individual computer code is presented. The results gained from...