Yazar "Tol, Guneyhan" seçeneğine göre listele

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    Experimental scale up techniques for PEMFC: Fluid mechanics approach
    (Pergamon-Elsevier Science Ltd, 2026) Tol, Guneyhan; Turkmen, Anil Can; Celik, Cenk; San, Fatma Gul Boyaci
    This study designs and manufactures three fuel cell sizes, varying only the active area, to evaluate the scaling effect on PEM fuel cell performance. Produced fuel cells with active areas of 50 cm2, 100 cm2 and 225 cm2 are experimentally tested under identical conditions. All cells are made of materials with identical properties. Flow rate calculations are based on the current density obtained from the active area size. A single-phase isothermal fluid mechanics model based on the finite element method is developed for all fuel cells to ensure that hydrogen flows at the same average linear velocity throughout channels of equal depth. Velocity calculations and pressure drops are analysed in the model for different stoichiometries. The model is validated by comparing pressure drops in the produced cells with model predictions. The performance of cells with the same active area as the only variable is compared under the same conditions.
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    Multi-criteria evaluation of hydrogen storage systems for geothermal backup power in Türkiye: The Kızıldere geothermal field
    (Pergamon-Elsevier Science Ltd, 2026) Boyaci-San, Fatma Gul; Sengun-Cetin, Raziye; Tol, Guneyhan; Tut-Haklidir, Fusun S.
    Among renewable energy sources, geothermal power plants stand out due to their high capacity factors and reliable, uninterrupted power generation, making them suitable for next-generation hydrogen systems. Effective on-site hydrogen production requires safe, efficient, and cost-effective storage technologies compatible with Proton Exchange Membrane (PEM) fuel cells. Given T & uuml;rkiye's expanding geothermal capacity, identifying transferable hydrogen storage solutions is critical. This study compares hydrogen storage methods using TOPSIS and WASPAS multi-criteria decision-making approaches based on gravimetric capacity, volumetric density, efficiency, safety, and cost. Both methods identify sodium borohydride (NaBH4) as the most suitable option.