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Optimum Alkaline Electrolyzer-Proton Exchange Membrane Fuel Cell Coupling in a Residential Solar Stand-Alone Power System
International Scholarly Research Network ISRN Renewable Energy Volume 2011, Article ID 953434, 13 pages doi:10.5402/2011/953434 Research Article Optimum Alkaline Electrolyzer-Proton Exchange Membrane Fuel Cell Coupling in a Residential Solar Stand-Alone Power System Hany A. Khater, Amr A. Abdelraouf, and Mohamed H. Beshr Department of Mechanical Power Engineering, Faculty of Engineering, Cairo University, P.O. Box 12211, Giza, Egypt Correspondence should be addressed to Mohamed H. Beshr, [email protected] Received 22 July 2011; Accepted 4 September 2011 Academic Editors: K. Kaygusuz and A. Stoppato Copyright © 2011 Hany A. Khater et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Modeling of an alkaline electrolyzer and a proton exchange membrane fuel cell (PEMFC) is presented. Also, a parametric study is performed for both components in order to determine the effect of variable operating conditions on their performance. The aim of this study is to determine the optimum operating conditions when the electrolyzer and the PEMFC are coupled together as part of a residential solar powered stand-alone power system comprising photovoltaic (PV) arrays, an alkaline electrolyzer, storage tanks, a secondary battery, and a PEMFC. The optimum conditions are determined based on an economic study which is performed to determine the cost of electricity (COE) produced from this system so as to determine the lowest possible COE. All of the calculations are performed using a computer code developed by using MATLAB. The code is designed so that any user can easily change the data concerning the location of the system or the working parameters of any of the system’s components to estimate the performance of a modified system. -
EFFECT of TEMPERATURE on PERFORMANCE of ADVANCED ALKALINE ELECTROLYZER Mohamad Azuan1,,Nor Zaihar Yahaya2,*,Amelia Melinda2,Muhammad Wasif Umar2 1,2Dept
Sci.Int.(Lahor),31(5),757-762,2019 ISSN 1013-5316;CODEN: SINTE 8 757 EFFECT OF TEMPERATURE ON PERFORMANCE OF ADVANCED ALKALINE ELECTROLYZER Mohamad Azuan1,,Nor Zaihar Yahaya2,*,Amelia Melinda2,Muhammad Wasif Umar2 1,2Dept. of Electrical & Electronic Engineering, Universiti Teknologi PETRONAS, 32610 Seri Iskandar, Perak, Malaysia For correspondence; Tel. + (60)175514728, E-mail: [email protected] For correspondence; Tel. + (60)125363696, E-mail: [email protected] ABSTRACT: Water electrolysis is one of the most widely used techniques for hydrogen production whereas alkaline electrolyzer is the most commercially available technology in industry. Conventionally, the industrial electrolyzers normally produce around 70 % efficiency. This low efficiency is due to high power dissipation in electrolysis process. In an ideal water electrolysis, the cell voltage is equal to the minimum reversible voltage which is 1.23 V for chemical reaction to take place in electrolysis process. However, this cell voltage is much higher in industrial electrolysis cells. This excess voltage is caused by the over voltage potential which increases the electrical impedance of an electrolysis cell causing a fraction of the applied energy to be wasted as heat while allowing the electric current passes through it. This paper aims to study the effect of temperature towards the I-U curve, over-voltage potentials, hydrogen flow rate and energy efficiency of an advanced alkaline electrolyzer. The simulation model is carried out at five different temperature levels varying between 20⁰ C and 100⁰ C. All related equations to the electrochemical reaction are modelled and simulated in MATLAB/Simulink. The results have shown that the temperature does not have an effect on the hydrogen flow rate but instead have a significant effect on the I-U curve, over voltage potentials and energy efficiency. -
Emilia Motoasca Avinash Kumar Agarwal Hilde Breesch Editors Energy Sustainability in Built and Urban Environments Energy, Environment, and Sustainability
Energy, Environment, and Sustainability Series Editors: Avinash Kumar Agarwal · Ashok Pandey Emilia Motoasca Avinash Kumar Agarwal Hilde Breesch Editors Energy Sustainability in Built and Urban Environments Energy, Environment, and Sustainability Series editors Avinash Kumar Agarwal, Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh, India Ashok Pandey, Distinguished Scientist, CSIR-Indian Institute of Toxicology Research, Lucknow, Uttar Pradesh, India This books series publishes cutting edge monographs and professional books focused on all aspects of energy and environmental sustainability, especially as it relates to energy concerns. The Series is published in partnership with the International Society for Energy, Environment, and Sustainability. The books in these series are editor or authored by top researchers and professional across the globe. The series aims at publishing state-of-the-art research and development in areas including, but not limited to: • Renewable Energy • Alternative Fuels • Engines and Locomotives • Combustion and Propulsion • Fossil Fuels • Carbon Capture • Control and Automation for Energy • Environmental Pollution • Waste Management • Transportation Sustainability More information about this series at http://www.springer.com/series/15901 Emilia Motoasca • Avinash Kumar Agarwal Hilde Breesch Editors Energy Sustainability in Built and Urban Environments 123 Editors Emilia Motoasca Hilde Breesch Department of Electrical Engineering Department of Civil Engineering KU Leuven (Catholic University Leuven) KU Leuven (Catholic University Leuven) Ghent, Belgium Ghent, Belgium Avinash Kumar Agarwal Department of Mechanical Engineering Indian Institute of Technology Kanpur Kanpur, Uttar Pradesh, India ISSN 2522-8366 ISSN 2522-8374 (electronic) Energy, Environment, and Sustainability ISBN 978-981-13-3283-8 ISBN 978-981-13-3284-5 (eBook) https://doi.org/10.1007/978-981-13-3284-5 Library of Congress Control Number: 2018961716 © Springer Nature Singapore Pte Ltd. -
Electroreduction of Carbon Monoxide to Liquid Fuel on Oxide-Derived Nanocrystalline Copper
LETTER doi:10.1038/nature13249 Electroreduction of carbon monoxide to liquid fuel on oxide-derived nanocrystalline copper Christina W. Li1, Jim Ciston2 & Matthew W. Kanan1 The electrochemical conversion of CO and H O into liquid fuel z z { {z { 2 2 2CO 3H2O 4e ?CH3CO2 3HO is ideal for high-density renewable energy storage and could pro- ð2Þ E~0:50 V versus RHE vide an incentive for CO2 capture. However, efficient electrocata- lysts for reducing CO and its derivatives into a desirable fuel1–3 are 2 By comparing OD-Cu to electrodes comprised of commercial Cu nano- not available at present. Although many catalysts4–11 can reduce CO 2 particles, we show that CO reduction activity is not a consequence of to carbon monoxide (CO), liquid fuel synthesis requires that CO is re- 1 nanocrystallite size or morphology; instead, we propose that grain boun- duced further, using H OasaH source. Copper (Cu) is the only known 2 daries participate in the catalysis. material with an appreciable CO electroreduction activity, but in bulk OD-Cu electrodes were prepared by annealing polycrystalline Cu form its efficiency and selectivity for liquid fuel are far too low for prac- foil in air at 500 C to grow a thick Cu O layer on the surface and sub- tical use. In particular, H O reduction to H outcompetes CO reduc- u 2 2 2 sequently reducing this oxide to form Cu0 nanocrystallites. We used tion on Cu electrodes unless extreme overpotentials are applied, at which two reduction methods to vary the properties of the material. -
Improving the Efficiency of PEM Electrolyzers Through Membrane
energies Article Improving the Efficiency of PEM Electrolyzers through Membrane-Specific Pressure Optimization Fabian Scheepers 1,* , Markus Stähler 1, Andrea Stähler 1, Edward Rauls 1 , Martin Müller 1, Marcelo Carmo 1 and Werner Lehnert 1,2 1 Forschungszentrum Juelich GmbH, Institute of Energy and Climate Research, IEK-14, Electrochemical Process Engineering, 52425 Juelich, Germany; [email protected] (M.S.); [email protected] (A.S.); [email protected] (E.R.); [email protected] (M.M.); [email protected] (M.C.); [email protected] (W.L.) 2 Faculty of Mechanical Engineering, RWTH Aachen University, 52072 Aachen, Germany * Correspondence: [email protected]; Tel.: +49-2461-61-2177 Received: 20 December 2019; Accepted: 23 January 2020; Published: 1 February 2020 Abstract: Hydrogen produced in a polymer electrolyte membrane (PEM) electrolyzer must be stored under high pressure. It is discussed whether the gas should be compressed in subsequent gas compressors or by the electrolyzer. While gas compressor stages can be reduced in the case of electrochemical compression, safety problems arise for thin membranes due to the undesired permeation of hydrogen across the membrane to the oxygen side, forming an explosive gas. In this study, a PEM system is modeled to evaluate the membrane-specific total system efficiency. The optimum efficiency is given depending on the external heat requirement, permeation, cell pressure, current density, and membrane thickness. It shows that the heat requirement and hydrogen permeation dominate the maximum efficiency below 1.6 V, while, above, the cell polarization is decisive. In addition, a pressure-optimized cell operation is introduced by which the optimum cathode pressure is set as a function of current density and membrane thickness. -
T~-:'Al of 10 Paces Only May Be Xeroxed
T~-:'AL OF 10 PACES ONLY MAY BE XEROXED DYNAMIC MODELING, SIMULATION AND CONTROL OF A SMALL WIND-FUEL CELL HYBRID ENERGY SYSTEM FOR STAND-ALONE APPLICATIONS by ©Mohammad Jahangir Alam Khan A thesis submitted to the School of Graduate Studies in partial fulfillment of the requirements for the degree of Master of Engineering Faculty of Engineering and Applied Science Memorial University of Newfoundland June 2004 St. John's Newfoundland Canada Library and Bibliotheque et 1+1 Archives Canada Archives Canada Published Heritage Direction du Branch Patrimoine de !'edition 395 Wellington Street 395, rue Wellington Ottawa ON K1A ON4 Ottawa ON K1A ON4 Canada Canada Your file Votre reference ISBN: 0-494-02350-3 Our file Notre reference ISBN: 0-494-02350-3 NOTICE: AVIS: The author has granted a non L'auteur a accorde une licence non exclusive exclusive license allowing Library permettant a Ia Bibliotheque et Archives and Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par telecommunication ou par I' Internet, preter, telecommunication or on the Internet, distribuer et vendre des theses partout dans loan, distribute and sell theses le monde, a des fins commerciales ou autres, worldwide, for commercial or non sur support microforme, papier, electronique commercial purposes, in microform, et/ou autres formats. paper, electronic and/or any other formats. The author retains copyright L'auteur conserve Ia propriete du droit d'auteur ownership and moral rights in et des droits moraux qui protege cette these. this thesis. Neither the thesis Ni Ia these ni des extraits substantiels de nor substantial extracts from it celle-ci ne doivent etre imprimes ou autrement may be printed or otherwise reproduits sans son autorisation. -
Efficiency – Electrolysis White Paper
Efficiency – Electrolysis White paper siemens-energy.com/electrolyzer White paper l Efficiency – Electrolysis Dr.l Philipp Lettenmeier Electrolysis In 1800, the two English scientists William Nicholson and Anthony Carlisle discovered direct current electrolysis, thereby establishing electrochemistry as a new scientific field. For a long time, electrolysis was the dominant tech- nology for the industrial generation of hydrogen. However, the increasing use of natural gas largely displaced this technology with the more cost-effective steam reforming. Now, over 200 years later, the splitting of water with elec- trical current is experiencing a renaissance. This is because this technology provides the possibility of converting and storing regenerative electric power in the form of hydrogen as a chemical energy source. In this process, traditional alkaline electrolysis is supplemented by the modern tech- nology of polymer electrolyte membrane (PEM) electrolysis. This is based on a publication by Russell et al. in 1973.1 The high reaction rate and the high power density make PEM electrolysis interesting with the use of fluctuating renew- able energy. The efficiency of the electrolysis systems is critical both technically and economically for electrochemical hydrogen generation using renewable energy.2 Hydrogen generation costs are primarily dominated by the relatively high power costs in addition to operating hours and amortization of the plant. From a technical standpoint, these costs can only be reduced by increasing overall efficiency. Efficiency is not just efficiency The following document is intended to illustrate for the The efficiency of two processes can reader what has to be taken into account when specifying only be compared if all of the reference or comparing efficiency levels for electrolysis systems. -
Cold Fusion Died 25 Years Ago, but the Research Lives on | November 7, 2016 Issue - Vol
11/7/2016 Cold fusion died 25 years ago, but the research lives on | November 7, 2016 Issue - Vol. 94 Issue 44 | Chemical & Engineering News 64.124.29.44 Volume 94 Issue 44 | pp. 34-39 Issue Date: November 7, 2016 COVER STORY Cold fusion died 25 years ago, but the research lives on Scientists continue to study unusual heat-generating effects, some hoping for vindication, others for and an eventual payday By Stephen K. Ritter Some 7,000 people attended a hastily organized cold fusion session at the ACS national meeting in Dallas in 1989, hopeful that word of the newly announced phenomenon was true. Credit: James Krieger/C&EN Howard J. Wilk is a long-term unemployed In brief synthetic organic chemist living in In 1989, the scientific world was turned upside down when two researchers announced they Philadelphia. Like many pharmaceutical had tamed the power of nuclear fusion in a researchers, he has suffered through the drug simple electrolysis cell. The excitement quickly died when the scientific community came to a industry’s R&D downsizing in recent years and consensus that the findings weren’t real—“cold fusion” became a synonym for junk science. In now is underemployed in a nonscience job. the quarter-century since, a surprising number of researchers continue to report unexplainable With extra time on his hands, Wilk has been excess heat effects in similar experiments, and several companies have announced plans to tracking the progress of a New Jersey-based commercialize technologies, hoping to company called Brilliant Light Power revolutionize the energy industry. -
Nuclear Glossary
NUCLEAR GLOSSARY A ABSORBED DOSE The amount of energy deposited in a unit weight of biological tissue. The units of absorbed dose are rad and gray. ALPHA DECAY Type of radioactive decay in which an alpha ( α) particle (two protons and two neutrons) is emitted from the nucleus of an atom. ALPHA (ααα) PARTICLE. Alpha particles consist of two protons and two neutrons bound together into a particle identical to a helium nucleus. They are a highly ionizing form of particle radiation, and have low penetration. Alpha particles are emitted by radioactive nuclei such as uranium or radium in a process known as alpha decay. Owing to their charge and large mass, alpha particles are easily absorbed by materials and can travel only a few centimetres in air. They can be absorbed by tissue paper or the outer layers of human skin (about 40 µm, equivalent to a few cells deep) and so are not generally dangerous to life unless the source is ingested or inhaled. Because of this high mass and strong absorption, however, if alpha radiation does enter the body through inhalation or ingestion, it is the most destructive form of ionizing radiation, and with large enough dosage, can cause all of the symptoms of radiation poisoning. It is estimated that chromosome damage from α particles is 100 times greater than that caused by an equivalent amount of other radiation. ANNUAL LIMIT ON The intake in to the body by inhalation, ingestion or through the skin of a INTAKE (ALI) given radionuclide in a year that would result in a committed dose equal to the relevant dose limit . -
The Grand Unified Theory of Classical Physics
THE GRAND UNIFIED THEORY OF CLASSICAL PHYSICS Volume 1 of 3 THE GRAND UNIFIED THEORY OF CLASSICAL PHYSICS BY Dr. Randell L. Mills September 3, 2016 Edition Volume 1 of 3 Copyright © 2016 by Dr. Randell L. Mills All rights reserved. No part of this work covered by copyright hereon may be reproduced or used in any form, or by any means-graphic, electronic, or mechanical, including photocopying, recording, taping, or information storage and retrieval systems-without written permission of Dr. Randell L. Mills. Manufactured in the United States of America. ISBN 978-0-9635171-5-9 Library of Congress Control Number 2015915593 i TABLE OF CONTENTS VOLUME 1 ATOMIC PHYSICS Preface ..................................................................................................................................................................................... xxv References ............................................................................................................................................................................... xxvi INTRODUCTION I.1 General Considerations ............................................................................................................................................... 1 I.2 CP Approach to the Solution of the Bound Electron .................................................................................................. 3 I.2.1 Spin and Orbital Parameters Arise from First Principles Only in the Case of CP............................................................................................................................................ -
Introduction to Nuclear Physics and Nuclear Decay
NM Basic Sci.Intro.Nucl.Phys. 06/09/2011 Introduction to Nuclear Physics and Nuclear Decay Larry MacDonald [email protected] Nuclear Medicine Basic Science Lectures September 6, 2011 Atoms Nucleus: ~10-14 m diameter ~1017 kg/m3 Electron clouds: ~10-10 m diameter (= size of atom) water molecule: ~10-10 m diameter ~103 kg/m3 Nucleons (protons and neutrons) are ~10,000 times smaller than the atom, and ~1800 times more massive than electrons. (electron size < 10-22 m (only an upper limit can be estimated)) Nuclear and atomic units of length 10-15 = femtometer (fm) 10-10 = angstrom (Å) Molecules mostly empty space ~ one trillionth of volume occupied by mass Water Hecht, Physics, 1994 (wikipedia) [email protected] 2 [email protected] 1 NM Basic Sci.Intro.Nucl.Phys. 06/09/2011 Mass and Energy Units and Mass-Energy Equivalence Mass atomic mass unit, u (or amu): mass of 12C ≡ 12.0000 u = 19.9265 x 10-27 kg Energy Electron volt, eV ≡ kinetic energy attained by an electron accelerated through 1.0 volt 1 eV ≡ (1.6 x10-19 Coulomb)*(1.0 volt) = 1.6 x10-19 J 2 E = mc c = 3 x 108 m/s speed of light -27 2 mass of proton, mp = 1.6724x10 kg = 1.007276 u = 938.3 MeV/c -27 2 mass of neutron, mn = 1.6747x10 kg = 1.008655 u = 939.6 MeV/c -31 2 mass of electron, me = 9.108x10 kg = 0.000548 u = 0.511 MeV/c [email protected] 3 Elements Named for their number of protons X = element symbol Z (atomic number) = number of protons in nucleus N = number of neutrons in nucleus A A A A (atomic mass number) = Z + N Z X N Z X X [A is different than, but approximately equal to the atomic weight of an atom in amu] Examples; oxygen, lead A Electrically neural atom, Z X N has Z electrons in its 16 208 atomic orbit. -
Comments on Evaluation of Al Electron-Capture and Positron
26 Comments on evaluation – CEA ISBN 2 7272 0211 3 Al Comments on evaluation of 26Al Electron-Capture and Positron Decay Data by Shiu-Chin Wu and E. Browne The Limitation of Relative Statistical Weight [2] (LWM) method, used for averaging numbers throughout this evaluation, provided a uniform approach for the analysis of discrepant data. The uncertainty assigned to the recommended values was always greater than or equal to the smallest uncertainty of the values used to calculate the average. Decay Scheme 26Al decays 100% by EC + b+ to 26Mg 2+ states at 1808.72 and 2938.41 keV. A measured relative emission probability for the positron annihilation radiation (511 keV) produced a total b+ branching of 82(2)% (72Sa02). This branching agrees well with a value of 81.7% predicted by theory[1]. Nuclear Data The recommended half-life of 26Al, 7.17(24) ´ 105 y, is a weighted average (c2/N-1=0.64, LWM) of 5 + 5 + 7.16(32) ´ 10 y, from partial T1/2 (b )= 8.73(30) ´ 10 y, b counting and mass spectrometric analysis [3], combined with b+(%)=82(2) from measurement of positron annihilation radiation (72Sa02)); 7.05(24) ´ 105 y, by specific activity and mass spectrometric analysis [4]; 7.8 (5) ´ 105 y, by specific activity from a source produced by 26Mg(p,n) 26Al (the number of 26Al atoms in the source were estimated by using the reaction cross section) [5]; and 7.02 (56) ´ 105 y, by counting the atoms of 26Al that did not disintegrate in the source (Accelerator Mass Spectrometry) [6].