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Article Citation - WoS: 24Citation - Scopus: 28Enhancing Proton Conductivity Via Sub-Micron Structures in Proton Conducting Membranes Originating From Sulfonated Pvdf Powder by Radiation-Induced Grafting(Elsevier Science Bv, 2018) Sadeghi, Sahl; Sanli, Lale Isikel; Guler, Enver; Gursel, Selmiye Alkan; Işıkel Şanlı, Lale; Alkan Gürsel, SelmiyeWe report here submicron-structured proton conducting poly(vinylidene fluoride)-graft-poly(styrene sulfonic acid) (PVDF-g-PSSA) membranes for polymer electrolyte membrane fuel cells (PEMFC). Highly conductive proton exchange membranes were obtained by single-step radiation grafting of sodium styrene sulfonate (SSS) to powder-form PVDF, followed by casting and subsequent solvent evaporation. The obtained submicron structure of membrane through solvent evaporation led to the arrangement of ionic channels proving increasing proton conductivity with the increase in graft level. In addition, a temperature above melting point of PVDF was used for solvent evaporation to allow melted PVDF to fill the formed pores, providing denser structure resulting in improved mechanical properties of the membranes. SSS grafting to PVDF powder was verified by NMR spectroscopy, and resultant membranes were characterized for proton conductivity, water up-take, morphology, mechanical and thermal properties, and fuel cell performance. According to preliminary tests, proton conductivities which were observed to increase with graft level were found to be around 70 mS cm(2) at 35% graft level. Thus, this led to a promising power density of 250 mW/cm(2) at 650 mA/cm(2).Conference Object Citation - WoS: 76Citation - Scopus: 92Modeling and Simulation of a Hybrid Photovoltaic (pv) Module-Electrolyzer Fuel Cell System for Micro-Cogeneration Applications(Pergamon-elsevier Science Ltd, 2015) Ozgirgin, Ekin; Devrim, Yilser; Albostan, AyhanThe rising cost of energy and power, depreciation of natural resources like fossil fuels and the global warming issues have all led the need for developing advanced clean energy systems. Hydrogen, which is clean energy carrier, can be produced by using solar electric energy from photovoltaic (PV) modules for the water electrolysis without emitting carbon dioxide. Modeling of PV module-electrolyzer hydrogen system is important for their planning and control strategies in many applications. In this respect, high-efficiency cogeneration systems for producing both heat and electricity coupled with clean energy sources such as PVs and fuel cells are gaining more attention, due to their advantages in terms of increasing efficiency and power quality, reducing harmful emissions and flexibility of operation. This study describes the analysis of the PV module-fuel cell hybrid system for house-hold micro co-generation applications. The system consists of PV modules, batteries, proton exchange membrane type water electrolyzer and proton exchange membrane fuel cell (PEMFC). The excess heat of PEMFC was used to supply hot water and/or heating energy of the house. Electrical energy was stored in the batteries. The analysis of the PV-electrolyzer-PEMFC system can be further used for designing co-generation systems for various application optimizing the PV module, electrolyzer and PEMFC sizes. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.Article Citation - WoS: 52Citation - Scopus: 57Examination of Compression Effects on Pemfc Performance by Numerical and Experimental Analyses(Pergamon-elsevier Science Ltd, 2020) Uzundurukan, Arife; Bilgili, Muhittin; Devrim, YilserIn the present study, the effects of compression method on Proton Exchange Membrane Fuel Cell (PEMFC) performance were investigated both numerically and experimentally. Total deformation of the components within the PEMFC was simulated by ANSYS threedimensional finite element analysis (3D FEA). Moreover, geometrical and material properties of all components of PEMFC such as bipolar plates (BPP), membrane electrode assembly (MEA), gasket, current collector plate (CCP), screw and nut were implemented for accurate simulation of compression. In the experimental part, PEMFC tests were performed with 25 cm(2) active area single cell having 3 channel parallel in series (3 PS) flow channel via PEMFC test station with H-2 and air at 60 degrees C. The maximum power density was achieved as 0.458 W/cm(2) and 0.480 W/cm(2) for bolt compression and clamping plates compression, respectively. The equivalent stress values were found as 120 MPa that under 4389 N the clamping plates and 1600 MPa under bolt compression with 1.3 Nm torque. When numerical and experimental studies are examined together, it is seen that bolt compression has higher deformation and less equivalent stress than clamping plates compression. (c) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
