Devrim, Yılser

Devrim, Yılser

Name Variants

D.,Yılser
Yilser, Devrim
Y.,Devrim
Devrim Y.
Devrim, Yılser
Güldogan, Y
Devrim, Yilser G.
D., Yilser
Yılser, Devrim
Devrim, YG
Devrim,Y.
Devrim, Yiser
D., Yılser
Devrim, Y. G.
D.,Yilser
Y., Devrim
Devrim, Yilser

Job Title

Profesor Doktor

Email Address

yilser.devrim@atilim.edu.tr

ORCID ID

0000-0001-8430-0702

Scopus Author ID

11139445500

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Scholarly Output

84

Articles

52

Citation Count

2249

Supervised Theses

9 Scholarly Output Search Results

Now showing 1 - 10 of 83

Pem Fuel Cell Short Stack Performances of Silica Doped Nanocomposite Membranes
(Pergamon-elsevier Science Ltd, 2015) Devrim, Yilser; Devrim, Huseyin; Energy Systems Engineering
In this study, an air-cooled Proton Exchange Membrane Fuel Cell (PEMFC) short stack with Nafion/Silica nanocomposite membrane was designed and fabricated for net 100 W net power output to improve the stack performance at low relative humidity conditions. Composite membrane was prepared by solution casting method. Gas Diffusion Electrodes (GDE's) were produced by ultrasonic spray coating technique. Short stack design was based on electrochemical data obtained at 0.60 V was 0.45 A/cm(2) from performance tests of a single cell having the same membrane electrode assemblies (MEA) that had an active area of 100 cm(2). The short stack was tested in the constant resistance load regime, in dead-end rode, with controlling temperature by air on-off control system. A maximum power of 117 W was obtained from the short stack. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Composite Membrane by Incorporating Sulfonated Graphene Oxide in Polybenzimidazole for High Temperature Proton Exchange Membrane Fuel Cells
(Pergamon-elsevier Science Ltd, 2022) Devrim, Yilser; Durmus, Gizem Nur Bulanik; Mechanical Engineering; Energy Systems Engineering
The objective of this work is to examine the polybenzimidazole (PBI)/sulfonated graphene oxide (sGO) membranes as alternative materials for high-temperature proton exchange membrane fuel cell (HT-PEMFC). PBI/sGO composite membranes were characterized by TGA, FTIR, SEM analysis, acid doping&acid leaching tests, mechanical analysis, and proton conductivity measurements. The proton conductivity of composite membranes was considerably enhanced by the existence of sGO filler. The enhancement of these properties is related to the increased content of -SO3H groups in the PBI/sGO composite membrane, increasing the channel availability required for the proton transport. The PBI/sGO membranes were tested in a single HT-PEMFC to evaluate high-temperature fuel cell performance. Amongst the PBI/sGO composite membranes, the membrane containing 5 wt. % GO (PBI/sGO-2) showed the highest HT-PEMFC performance. The maximum power density of 364 mW/cm(2) was yielded by PBI/sGO-2 membrane when operating the cell at 160 degrees C under non humidified conditions. In comparison, a maximum power density of 235 mW/cm(2) was determined by the PBI membrane under the same operating conditions. To investigate the HT-PEMFC stability, long-term stability tests were performed in comparison with the PBI membrane. After a long-term performance test for 200 h, the HT-PEMFC performance loss was obtained as 9% and 13% for PBI/sGO-2 and PBI membranes, respectively. The improved HT-PEMFC performance of PBI/sGO composite membranes suggests that PBI/sGO composites are feasible candidates for HT-PEMFC applications. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Development of Effective Bimetallic Catalyst for High-Temperature Pem Fuel Cell To Improve Co Tolerance
(Wiley, 2021) Al-Tememy, Mogdam Gassy Hussein; Devrim, Yilser; Energy Systems Engineering
In this study, it is aimed to examine the effect of multi-walled carbon nanotube doped graphene nanoplatelet (MWCNT-GNP) supported PtPd bimetallic catalyst on the performance of the high-temperature proton-exchange membrane fuel cell (HT-PEMFC). In addition, PtPd/GNP and PtPd/MWCNT bimetallic catalysts were also investigated for performance comparison. The characterizations of these catalysts were examined by ICP-MS, XRD, HR-TEM, and TGA analysis. The electrochemical characterizations of the catalysts were performed for both cyclic voltammetry (CV) and CO stripping experiments, as well as HT-PEMFC tests. The specific surface area (SSA) for PtPd/GNP and PtPd/MWCNT catalysts was obtained as 148 and 137 m(2)/g, respectively, while the highest SSA was achieved as 164 m(2)/g for PtPd/MWCNT-GNP. The performance of the catalysts was confirmed with the HT-PEMFC tests, based on the H-2/air and reformate gas/air experiments. The electrocatalytic results display that PdPt bimetallic catalysts exhibited higher catalytic property than that of commercial Pt/C catalyst. The highest performance was achieved with PtPd/MWCNT-GNP catalyst as 0.390 and 0.310 W/cm(2)at 160 degrees C for H-2/air and reformat/air, respectively. The obtained results indicate that the PtPd/MWCNT-GNP catalyst is appropriate for HT-PEMFC operations.
Computing Reliability Indices of a Wind Power System Via Markov Chain Modelling of Wind Speed
(Sage Publications Ltd, 2024) Eryilmaz, Serkan; Bulanik, Irem; Devrim, Yilser; Industrial Engineering; Energy Systems Engineering
Statistical modelling of wind speed is of great importance in the evaluation of wind farm performance and power production. Various models have been proposed in the literature depending on the corresponding time scale. For hourly observed wind speed data, the dependence among successive wind speed values is inevitable. Such a dependence has been well modelled by Markov chains. In this paper, the use of Markov chains for modelling wind speed data is discussed in the context of the previously proposed likelihood ratio test. The main steps for Markov chain based modelling methodology of wind speed are presented and the limiting distribution of the Markov chain is utilized to compute wind speed probabilities. The computational formulas for reliability indices of a wind farm consisting of a specified number of wind turbines are presented through the limiting distribution of a Markov chain. A case study that is based on real data set is also presented.
Yeşil Hidrojen Temelli Hibrit Enerji Sisteminin Modellenmesi, Simülasyonu ve Tasarımı
(2022) Özkök, Duygu; Devrim, Yılser; Energy Systems Engineering
Küresel ısınma arttıkça ve fosil yakıt kaynakları tükendikçe yenilenebilir enerji kaynakları önem kazanmaktadır. Güneş ışığı, rüzgar, jeotermal enerjiler ve hidro enerji gibi temiz enerji kaynakları yenilenebilir enerji kaynaklarını oluşturur. Güneşin ve rüzgarın sonsuz kaynak olması yenilenebilir enerjiyi gün geçtikçe daha önemli hale getirmektedir. Ayrıca, dışa bağımlılığı azaltması da yenilenebilir enerji kaynaklarının önemini daha da arttırmaktadır. Ülkemiz gerek güneş ışınımı gerekse rüzgar potansiyeli yönünden oldukça verimli bir konuma sahiptir. Bu da güneş enerjisi ve rüzgar enerjisinden elektrik üretimini daha da önemli hale getirmektedir. Ancak ,yenilenebilir enerji kaynaklarının mevcut yüksek başlangıç maliyetleri ve düşük enerji dönüşüm verimlilikleri yenilenebilir enerjinin kullanılabilirlik durumunu azaltmaktadır. Güneş enerjisinden elektrik üretiminin akşam saatlerinde yapılmaması da kesintilere yol açmaktadır. Bu yüzden birbirini tamamlayıcı sistemler olarak güneş ve rüzgar enerji sistemleri entegrasyonu kullanılmaktadır. İki ya da daha fazla yenilenebilir enerji kaynağının bir arada kullanılmasına hibrit sistemleri denir. Tek bir yenilenebilir enerji kaynağının kullanılmasından ziyade hibrit sisteminin kullanımı hem maliyet açısından daha avantajlı hem de verimlilik açısından daha avantajlıdır. Tek sistem olarak kurulu kaynaklardan oluşabilecek kesintili elektrik sorunu, güneş-rüzgar enerjisi entegrasyonunda kurulan sistem çözebilir. Güneşin gündüz saatlerinde elektrik üretmesi ve rüzgarın akşam saatlerinde elektrik üretmesi birbirini tamamlayıcı özellik sağlar. Yenilenebilir enerji kaynaklarında karşılaşabilinecek diğer bir sorun ise depolamadır. Bilindiği gibi güneş enerjisinde kullanılan bataryalar mevsimsel depolama yapmamaktadır. Bu da fazla üretilen elektriğin kullanılamayacağını gösterir. Bu yüzden alternatif enerji kaynağı olarak hidrojen enerjisi devreye girer. Enerjinin hidrojen şeklinde depolanması hem günlük hem de mevsimsel depolama için çözüm oluşturur. Elektrölizör yardımıyla su molekülleri hidrojen (H2) ve oksijene (O2) ayrıştırılır ve yüksek basınçlı tanklarda H2 ve O2 olarak depolanır. Yakıt hücreleri de bu sistemde hidrojenin oluşturduğu kimyasal enerjiyi elektrik enerjisine dönüştüren bir kaynaktır. Güneş-rüzgar sistemine entegre edilen yakıt hücreleri de enerji dönüşümünü yükseltmek açısından alternatif bir çözümdür. Yakıt hücresi türleri içinde proton değişim membranlı yakıt hücresi (PEMYH) sessiz çalışma ve daha düşük korozyon, yüksek güç yoğunluğu, düşük yerel emisyonlar, düşük çalışma sıcaklıkları gibi özelliklerinden dolayı en çekici olanıdır. Bu nedenle fotovoltaik paneller ve rüzgar türbinleri bulunan hibrit sistemler için PEMYH ile çalıştırılabilirler. Yenilenebilir enerji kaynaklarının çalışmalarındaki en önemli süreci simülasyon adımları oluşturmaktadır. Bu tez çalışması, Ankara Atılım Üniversitesinin 25 kW'lık elektrik ihtiyacını şebekeye bağlı olmadan, hibrit sistemlerden karşılamak için yapılmıştır. Sistem depolama sorunun çözmek için hidrojen enerjisi ve buna bağlı olarak yakıt hücresi tasarlanmıştır. Günde 5 saat çalışacak PEMYH tasarımı MATLAB program aracılığıyla tasarlanmış ve TRNSYS programına entegre edilmiştir. Sistem simülasyonu TRNSYS programı kullanılarak yapılmıştır. Elektrölizörün çalışması için sabit sayıda seçilen rüzgar türbinlerine göre optimum panel sayısı belirlenmiştir. Son olarak Seviyelendirilmiş maliyet hesaplamaları hesaplanarak ve optimum sistem belirlenmiştir.
Design and Simulation of the Pv/Pem Fuel Cell Based Hybrid Energy System Using Matlab/Simulink for Greenhouse Application
(Pergamon-elsevier Science Ltd, 2021) Ceylan, Ceren; Ceylan, Ceren; Devrim, Yilser; Devrim, Yılser; Ceylan, Ceren; Devrim, Yılser; Energy Systems Engineering; Energy Systems Engineering
In this study, design and optimization of the hybrid renewable energy system consisting of Photovoltaic (PV)/Electrolyzer/Proton Exchange Membrane Fuel Cell (PEMFC) was investigated to provide electricity and heat for Greenhouse in Sanhurfa (Turkey). The coupling of a photovoltaic system with PEMFC was preferred to supply continuous production of electric energy throughout the year. Additionally, produced heat from PEMFC was used to heating of the greenhouse by micro cogeneration application. The MATLAB/Simulink was applied to the design and optimization of the proposed hybrid system. In the designed system, solar energy was selected to produce the Hydrogen (H-2) required to run the electrolyzer. In cases where the solar energy is not sufficient and cannot meet the electricity requirement for the electrolyzer; the H-2 requirement for the operation of the PEMFC was met from the H-2 storage tanks and energy continuity was ensured. The electrolyzer was designed for H-2 demand of the 3 kW PEMFC which were met the greenhouse energy requirement. PEMFC based hybrid system has 48% electrical and 45% thermal efficiencies. According to optimization results obtained for the proposed hybrid system, the levelized cost of energy was found 0.117 $/kWh. The obtained results show the proposed PV/Electrolyzer/PEMFC hybrid power system provides an applicable option for powering stand-alone application in a self sustainable expedient. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
DEVELOPMENT OF BIMETALLIC ELECTROCATALYSTS FOR HIGH-TEMPERATURE ELECTROCHEMICAL HYDROGEN PURIFICATION
(International Association for Hydrogen Energy, IAHE, 2022) Bal,İ.B.; Durmuş,G.N.B.; Devrim,Y.; Mechanical Engineering; Energy Systems Engineering
In this study, PtRu/GNP, PtIr/GNP, and RuIr/GNP bimetallic catalysts were synthesized by microwave-assisted synthesis method, and their performances on the high-temperature electrochemical hydrogen purification (HT-ECHP) were compared. The structural and electrochemical characteristics of the bimetallic catalysts were examined by the TGA, XRD, XPS, and CV techniques. ECHP Tests were performed with reformate gas mixtures containing hydrogen (H2), carbon monoxide (CO), and carbon dioxide (CO2) at temperatures between 140-180°C. The gas at the exit of the ECHP cell was analyzed with the gas chromatography device (GC), and high H2 purity was achieved. © 2022 Proceedings of WHEC 2022 - 23rd World Hydrogen Energy Conference: Bridging Continents by H2. All rights reserved.
Polybenzimidazole/Sio_{2< Hybrid Membranes for High Temperature Proton Exchange Membrane Fuel Cells}
(Pergamon-elsevier Science Ltd, 2016) Devrim, Yilser; Devrim, Huseyin; Eroglu, Inci; Energy Systems Engineering
Polybenzimidazole/Silicon dioxide (PBI/SiO2) hybrid membranes were prepared and characterized as alternative materials for high temperature proton exchange membrane fuel cell (HT-PEMFC). The PBI/SiO2 membranes were cast from a PBI polymer synthesized in the laboratory and contained 5 wt. % SiO2 as inorganic filler. Scanning electron microscopy (SEM) analysis showed that the uniform and homogeneous distribution of SiO2 particles in the hybrid membrane. The existence SiO2 has improved the acid retention and proton conductivity properties. A maximum conductivity of 0.1027 S/cm at 180 degrees C was obtained for the PBI/SiO2 hybrid membrane. Gas diffusion electrodes (GDE) were fabricated by ultrasonic coating technique with 1 mg Pt/cm(2) catalyst loading for both anode and cathode. The membranes were tested in a single HT-PEMFC with a 5 cm(2) active area operating at the temperature range of 140 degrees C-180 degrees C. Single HT-PEMFC tests indicated that PBI/SiO2 hybrid membrane was more stable and also performed better than pristine PBI membrane. Maximum current density was observed for PBI/SiO2 membrane at 165 degrees C and cell voltage of 0.6 V as 0.24 A/cm(2). The results suggested that PBI/SiO2 hybrid membrane is promising electrolytes for HT-PEMFC with improved fuel cell performance. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Performance Analysis of a Gas-To System Based on Protonic-Ceramic Electrochemical Compressor
(Pergamon-elsevier Science Ltd, 2023) Baniasadi, Ehsan; Ghojavand, Fateme; Colpan, Can Ozgur; Devrim, Yilser; Energy Systems Engineering
In this study, two scenarios are considered to evaluate the performance of a protonic ceramic electrochemical hydrogen compressor (EHC) and reformer integrated with a pro-ton exchange membrane fuel cell (PEMFC). First scenario includes integration of an EHC with PEMFC and in the second scenario, steam methane reforming (SMR) is replaced by an EHC. Results show that the highest energy and exergy efficiencies of the system in the first scenario is achieved when the area-specific resistance (ASR) in EHC is 1.5 Ucm2. An in-crease in the working temperature of EHC causes a considerable rise in the exergy destruction and an increase of energy efficiency by 7% in the first scenario, while the temperature of the reformer affects the exergy destruction, negligibly. The parametric study indicates that the best value of the current density of PEMFC is 0.8481 A/cm2 and 0.8324 A/cm2 and the best current density of PEM-EHC value is 0.4468 A/cm2 and 0.11 A/cm2 in the 1st and 2nd scenarios, respectively. Under the same conditions, energy and exergy efficiencies for the first scenario are 61.63% and 54.9% and for the second scenario are 42.48% and 14.61%, respectively.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Investigation of the Performance of High-Temperature Electrochemical Hydrogen Purification From Reformate Gases
(Wiley, 2022) Durmus, Gizem Nur Bulanik; Durmuş, Gizem Nur Bulanık; Colpan, C. Ozgur; Devrim, Yilser; Devrim, Yılser; Durmuş, Gizem Nur Bulanık; Devrim, Yılser; Mechanical Engineering; Energy Systems Engineering; Energy Systems Engineering; Mechanical Engineering; Energy Systems Engineering
In the present work, the purification of hydrogen from a hydrogen/carbon dioxide/carbon monoxide (H-2:CO2:CO) mixture by a high-temperature electrochemical purification (HT-ECHP) system is examined. Electrochemical H-2 purification experiments were carried out in the temperature range of 140-180 degrees C. The effects of the molar ratio of the gases in the mixture (H-2:CO2:CO-75:25:0, H-2:CO2:CO-72:26:2,0 H-2:CO2:CO-75:22:3, H-2:CO2:CO-75:20:5, H-2:CO2:CO-97:0:3, H-2:CO2:CO-95:0:5) and the operating temperature on the electrochemical H-2 separation were investigated. As a result of the electrochemical H-2 purification experiments, it was determined that the operating temperature is the most important parameter affecting the performance. According to the results obtained, H-2 purity of 99.999% was achieved at 160 degrees C with the reformate gas mixture containing 72% H-2, 26% CO2, and 2% CO by volume. According to the polarization curves of the gas mixtures containing CO, high current densities at low voltage were reached at 180 degrees C, and it was observed that the performance increased as the temperature increased, whereas the gas mixture without CO gave the best performance at 160 degrees C.

Devrim, Yılser

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Scholarly Output

84

Articles

52

Citation Count

2249

Supervised Theses

9

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