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Conference Object Citation - WoS: 90Citation - Scopus: 107Modeling and Sensitivity Analysis of High Temperature Pem Fuel Cells by Using Comsol Multiphysics(Pergamon-elsevier Science Ltd, 2016) Sezgin, Berna; Caglayan, Dilara Gulcin; Devrim, Yilser; Steenberg, Thomas; Eroglu, InciThe objective of this study is to observe the effect of the critical design parameters, velocities of inlet gases (hydrogen and air) and the conductivity of polymer membrane, on the performance of a high temperature PEM fuel cell. A consistent and systematic mathematical model is developed in order to study the effect of these parameters. The model is applied to an isothermal, steady state, three-dimensional PEM fuel cell in order to observe concentration profiles, current density profiles and polarization curves. The model includes the transport of gases in anode and cathode gas flow channels, diffusion in the catalyst layers, the transport of water and hydronium ion in the polymer electrolyte and in the catalyst layers, and the transport of electrical current in the solid phase. The model is considered as having a single flow channel. The simulation is performed by using licensed Comsol Multiphysics 5.0, Fuel Cells &Batteries Module. The results compare well with the experimental polarization data obtained at 160 degrees C for ohmic and activation regions. The best match with the experimental data is obtained when the inlet hydrogen gas velocity is 0.133 m/s whereas inlet air velocity is 1.3 m/s for proton conductivity of 10 S/m. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Conference Object Citation - WoS: 44Citation - Scopus: 56Three-Dimensional Modeling of a High Temperature Polymer Electrolyte Membrane Fuel Cell at Different Operation Temperatures(Pergamon-elsevier Science Ltd, 2016) Caglayan, Dilara Gulcin; Sezgin, Berna; Devrim, Yilser; Eroglu, InciA three-dimensional model for a high temperature polymer electrolyte membrane (PEM) fuel cell having an active area of 25 cm(2) is developed. Triple mixed serpentine flow channel single cell with phosphoric acid doped polybenzimidazole (FBI) membrane is used in the model. Steady-state, isothermal, single phase assumptions are defined for the system. The model is simulated at different temperatures ranging from 100 to 180 degrees C to investigate the influence of operation temperature on the performance of the cell. It is seen that there is an improvement in the performance of the cell as the operation temperature increases. Experimental data are used to validate the model both for single channel and triple mixed serpentine flow channel. Current density distribution is obtained at different operating voltages. The predicted results show that at high operating voltages the local current density is almost uniform; whereas, decreasing operating voltage causes non-uniformities in the local current density. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Conference Object Citation - WoS: 58Citation - Scopus: 62Energy and Exergy Performance Assessments of a High Temperature-Proton Exchange Membrane Fuel Cell Based Integrated Cogeneration System(Pergamon-elsevier Science Ltd, 2020) Nalbant, Yagmur; Colpan, C. Ozgur; Devrim, YilserHigh-temperature proton exchange membrane fuel cell (HT-PEMFC), which operates between 160 degrees C and 200 degrees C, is considered to be a promising technology, especially for cogeneration applications. In this study, a mathematical model of a natural gas fed integrated energy system based on HT-PEMFC is first developed using the principles of electrochemistry and thermodynamics (including energy and exergy analyses). The effects of some key operating parameters (e.g., steam-to-carbon ratio, HT-PEMFC operating temperature, and anode stoichiometric ratio) on the system performance (electrical, cogeneration, and exergetic efficiencies) are examined. The exergy destruction rates of each component in the integrated system are found for different values of these parameters. The results show that the most influential parameter which affects the performance of the integrated system is the anode stoichiometric ratio. For the baseline conditions, when the anode stoichiometric ratio increases from 1.2 to 2, the electrical, cogeneration, and exergetic efficiencies decrease by 42.04%, 33.15%, and 37.39%, respectively. The highest electrical power output of the system is obtained when the SCR, operating temperature, and anode stoichiometric ratio are taken as 2, 160 degrees C, and 1.2, respectively. For this case, the electrical, cogeneration, and exergetic efficiencies are found as 26.20%, 70.34%, and 26.74%, respectively. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Conference Object Citation - WoS: 34Citation - Scopus: 39Development of a One-Dimensional and Semi-Empirical Model for a High Temperature Proton Exchange Membrane Fuel Cell(Pergamon-elsevier Science Ltd, 2018) Nalbant, Yagmur; Colpan, C. Ozgur; Devrim, YilserHigh temperature proton exchange membrane fuel cells (HT-PEMFC), which operate between 160 degrees C and 200 degrees C, can be generally used in portable and stationary power generation applications. In this study, a one-dimensional, semi-empirical, and steady-state model of a HT-PEMFC fed with a gas mixture consisting of hydrogen and carbon monoxide is developed. Some modeling parameters are adjusted using empirical data, which are obtained conducting experiments on a HT-PEMFC for different values of Pt loading and cell temperature. For adjusting these parameters, the total summation of the square of the difference between the cell voltages found using the experimental and theoretical methods is minimized using genetic algorithm. After finding the values of the adjusted parameters, the effects of different cell temperature, Pt loading, phosphoric acid (PA) percentage, and different binders (PBI and PVDF) on the performance of the fuel cell are examined. It was found that, the performance of the fuel cell using PVDF binder exhibited better performance as compared to that using PBI binder. (c) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
