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    Effects of bolt torque and contact resistance on the performance of the polymer electrolyte membrane electrolyzers
    (ELSEVIER SCIENCE BV, 2015) Selamet, Omer F.; Ergoktas, M. Said
    The effect of bolt torque and contact resistance on the performance of Proton Exchange Membrane (PEM) Electrolyzers are investigated by a 50 cm(2) cell. The cell is designed and manufactured in house. The performance and contact resistance of the cell with three different gasket materials for demanding bolt torques are measured. The pressure distribution inside the cell is obtained by using pressure sensitive films. The pressure acting on the membrane electrode assembly (MEA) is calculated by analyzing and quantifying intensities of pressure film images. 3D plots of pressure distribution for predefined bolt torque values are obtained to understand the pressure distribution over the active area. The performance of the cell is enhanced when bolt torque is increased. However, beyond a value, relatively weak cell components such as diffusion layers are damaged and performance loss is observed due to the mass transfer limitations. The best efficiency is reached at 15 Nm bolt torque for Polytetrafiuoroethylene (PTFE) and Ethylene Propylene Diene Monomer (EPDM) gaskets. For silicon gasket best efficiency is reached at 15 Nm at lower current densities and at 10 Nm at higher current densities. Increasing clamping pressure is found to be developing more contact points between the interfaces and results in decrease in contact resistance inside the cell. (C) 2015 Elsevier B.V. All rights reserved.
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    Effects of operating parameters on the performance of a high-pressure proton exchange membrane electrolyzer
    (WILEY-BLACKWELL, 2013) Selamet, Omer F.; Acar, M. Caner; Mat, Mahmut D.; Kaplan, Yuksel
    In this study, a 100-cm2 single-cell and a 10-cell stack PEM electrolyzers are designed and manufactured, and the effects of operating parameters such as temperature, pressure, and feed water flow rate on the performance of the PEM electrolyzer are investigated. The hydrogen production capacity of the 10-cell stack is measured to be 7 NL/min hydrogen at 1 A/cm2 current density and atmospheric pressure. Both the single-cell and the 10-cell stack can directly supply both oxygen and hydrogen gases up to 50 bars. The operating temperature is found to be most important parameter affecting on the performance. An 87% efficiency is achieved in single cell at 80 degrees C and 1 A/cm2 current density. Copyright (c) 2012 John Wiley & Sons, Ltd.