Devrim, Yılser
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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
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
Main Affiliation
Energy Systems Engineering
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WoS Researcher ID
Scholarly Output
84
Articles
52
Citation Count
2249
Supervised Theses
9
83 results
Scholarly Output Search Results
Now showing 1 - 10 of 83
Article Citation - WoS: 15Citation - Scopus: 22Pem Fuel Cell Short Stack Performances of Silica Doped Nanocomposite Membranes(Pergamon-elsevier Science Ltd, 2015) Devrim, Yilser; Devrim, Huseyin; Energy Systems EngineeringIn 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.Article Citation - WoS: 59Citation - Scopus: 70Evaluation of Sulfonated Polysulfone/Zirconium Hydrogen Phosphate Composite Membranes for Direct Methanol Fuel Cells(Pergamon-elsevier Science Ltd, 2017) Ozden, Adnan; Ercelik, Mustafa; Devrim, Yilser; Colpan, C. Ozgur; Hamdullahpur, Feridun; Energy Systems EngineeringDirect methanol fuel cell (DMFC) technology has advanced perceivably, but technical challenges remain that must be overcome for further performance improvements. Thus, in this study, sulfonated polysulfone/zirconium hydrogen phosphate (SPSf/ZrP) composite membranes with various sulfonation degrees (20%, 35%, and 42%) and a constant concentration of ZrP (2.5%) were prepared to mitigate the technical challenges associated with the use of conventional Nafion (R) membranes in DMFCs. The composite membranes were investigated through Scanning Electron Microscopy (SEM), Electrochemical Impedance Spectroscopy (EIS), Thermogravimetric Analysis (TGA), oxidative stability and water uptake measurements, and single cell testing. Comparison was also made with Nafion (R) 115. Single cell tests were performed under various methanol concentrations and cell temperatures. Stability characteristics of the DMFCs under charging and discharging conditions were investigated via 1200 min short-term stability tests. The response characteristics of the DMFCs under dynamic conditions were determined at the start-up and shut-down stages. Composite membranes with sulfonation degrees of 35% and 42% were found to be highly promising due to their advanced characteristics with respect to proton conductivity, water uptake, thermal resistance, oxidative stability, and methanol suppression. For the whole range of parameters studied, the maximum power density obtained for SPSf/ZrP-42 (119 mW cm (2)) was found to be 13% higher than that obtained for Nafion (R) 115 (105 mW cm (2)). (C) 2017 Elsevier Ltd. All rights reserved.Article Atılan 1 Ton Çöp Değil 1 Mw Elektrik(2022) Devrim, Yılser; Sağlam, Arife; Energy Systems EngineeringMaddenin katı, sıvı, gaz ve plazma olmak üzere dört hali olduğu bilinmektedir. Maddenin plazma hali bir enerji kaynağı olarak görüldüğünden maddenin diğer üç halinden ayrı tutulmaktadır. Plazma teknolojisi ilk olarak 1929 yılında Amerikalı bilim adamı Irving Langmuir tarafından elektrik deşarjı sırasında salınım yapan elektron bulutunu tanımlamak üzere “plazma” teriminin kullanması ile başladı.Conference Object Citation - WoS: 67Citation - Scopus: 75Graphene Based Catalyst Supports for High Temperature Pem Fuel Cell Application(Pergamon-elsevier Science Ltd, 2018) Devrim, Yilser; Arica, Elif Damla; Albostan, Ayhan; Energy Systems EngineeringIn this study, the effect of graphene nanoplatelet (GNP) and graphene oxide (GO) based carbon supports on polybenzimidazole (PBI) based high temperature proton exchange membrane fuel cells (HT-PEMFCs) performances were investigated. Pt/GNP and Pt/GO catalysts were synthesized by microwave assisted chemical reduction support. X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Brauner, Emmet and Teller (BET) analysis and high resolution transmission electron microscopy (HRTEM) were used to investigate the microstructure and morphology of the as-prepared catalysts. The electrochemical surface area (ESA) was studied by cyclic voltammetry (CV). The results showed deposition of smaller Pt nanoparticles with uniform distribution and higher ECSA for Pt/GNP compared to Pt/GO. The Pt/GNP and Pt/GO catalysts were tested in 25 cm(2) active area single HT-PEMFC with H-2/air at 160 degrees C without humidification. Performance evaluation in HT-PEMFC shows current densities of 0.28, 0.17 and 0.22 A/cm(2) for the Pt/GNP, Pt/C and Pt/GO catalysts based MEAs at 160 degrees C, respectively. The maximum power density was obtained for MEA prepared by Pt/GNP catalyst with H-2/Air dry reactant gases as 0.34, 0.40 and 0.46 W/cm(2) at 160 degrees C, 175 degrees C and 190 degrees C, respectively. Graphene based catalyst supports exhibits an enhanced HT-PEMFC performance in both low and high current density regions. The results indicate the graphene catalyst support could be utilized as the catalyst support for HT-PEMFC application. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Conference Object Citation - Scopus: 0PARAMETER OPTIMIZATION OF A PBI MEMBRANE-BASED HIGH TEMPERATURE-ELECTROCHEMICAL HYDROGEN COMPRESSOR FED WITH H2 AND CO MIXTURE(International Association for Hydrogen Energy, IAHE, 2022) Kuzu,C.; Ozgur Colpan,C.; Durmuş,G.N.B.; Devrim,Y.; Mechanical Engineering; Energy Systems EngineeringIn today's world, the increase in the amount of energy needed with the increase in the human population and the depletion of fossil fuels has pushed researchers to search for alternative fuels. Hydrogen is expected to take an important share among the alternative fuels in the future. However, it has some challenges in terms of its storage and pressurization. In this study, the effect of back diffusion on the performance of a PBI membrane-based electrochemical hydrogen compressor operating at 160 °C. Pressure values are calculated and validated with experimental results; and the change of flux, voltage and cell efficiency with time are presented. © 2022 Proceedings of WHEC 2022 - 23rd World Hydrogen Energy Conference: Bridging Continents by H2. All rights reserved.Conference Object Citation - WoS: 0Optimization of modeling parameters of of a direct dimethyl ether fuel cell (DDMEFC)(Ieee, 2019) Alpaydin, Guvenc Umur; Colpan, C. Ozgur; Devrim, Yilser; Energy Systems EngineeringDirect alcohol fuel cells are one of the suitable candidates for sustainable power generation in portable applications. Among the different alcohol types that can be used in these fuel cells, DME, which is almost non-toxic at room temperature and easy to liquefy, and has a molecular structure similar to methanol, is one of the suitable options. For this reason, many studies have been carried out to develop direct dimethyl ether fuel cell (DDMEFC). Mathematical modeling studies also play an important role in the development of DDMEFC since they enable the understanding of the performance of the fuel cells more thoroughly. In this study, a model has been developed by using the principles of conservation chemical species and electrochemistry. A modeling study was performed using MATLAB. The values of some modeling parameters were estimated using the genetic algorithm optimization technique.Conference Object Citation - WoS: 83Citation - Scopus: 87Experimental Investigation of Co Tolerance in High Temperature Pem Fuel Cells(Pergamon-elsevier Science Ltd, 2018) Devrim, Yilser; Albostan, Ayhan; Devrim, Huseyin; Energy Systems EngineeringIn the present work, the effect of operating a high temperature proton exchange membrane fuel cell (HT-PEMFC) with different reactant gases has been investigated throughout performance tests. Also, the effects of temperature on the performance of a HT-PEMFC were analyzed at varying temperatures, ranging from 140 degrees C to 200 degrees C. Increasing the operating temperature of the cell increases the performance of the HT-PEMFC. The optimum operating temperature was determined to be 160 degrees C due to the deformations occurring in the cell components at high working temperatures. To investigate the effects of CO on the performance of HT-PEMFC, the CO concentration ranged from 1 to 5 vol %. The current density at 0.6 V decreases from 0.33 A/cm(2) for H-2 to 0.31 A/cm(2) for H-2 containing 1 vol % CO, to 0.29 A/cm(2) for 3 vol % CO, and 0.25 A/cm(2) for 5 vol % CO, respectively. The experimental results show that the presence of 25 vol % CO2 or N-2 has only a dilution effect and therefore, there is a minor impact on the HT-PEMFC performance. However, the addition of CO to H-2/N-2 or H-2/CO2 mixtures increased the performance loss. After longterm performance test for 500 h, the observed voltage drop at constant current density was obtained as similar to 14.8% for H-2/CO2/CO (75/22/3) mixture. The overall results suggest that the anode side gas mixture with up to 5 vol % CO can be supplied to the HT-PEMFC stack directly from the reformer. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Conference Object Citation - WoS: 25Citation - Scopus: 28Investigation of the effect of graphitized carbon nanotube catalyst support for high temperature PEM fuel cells(Pergamon-elsevier Science Ltd, 2020) Devrim, Yilser; Arica, Elif Damla; Energy Systems EngineeringIn this study, it is aimed to investigate the graphitization effect on the performance of the multi walled carbon nanotube catalyst support for high temperature proton exchange membrane fuel cell (HT-PEMFC) application. Microwave synthesis method was selected to load Pt nanoparticles on both CNT materials. Prepared catalyst was analyzed thermal analysis (TGA), Transmission Electron Microscopy (TEM) and corrosion tests. TEM analysis proved that a distribution of Pt nanoparticles with a size range of 2.8-3.1 nm was loaded on the Pt/CNT and Pt/GCNT catalysts. Gas diffusion electrodes (GDE) were manufactured by an ultrasonic spray method with synthesized catalyst. Polybenzimidazole (PBI) membrane based Membrane Electrode Assembly (MEA) was prepared for observe the performance of the prepared catalysts. The synthesized catalysts were also tested in a HT-PEMFC environment with a 5 cm(2) active area at 160 degrees C without humidification. This study demonstrates the feasibility of using the microwave synthesis method as a fast and effective method for preparing high performance Pt/CNT and Pt/GCNT catalyst for HT-PEMFC. The HT-PEMFC performance evaluation shows current densities of 0.36 A/cm(2)0.30 A/cm(2) and 0.20 A/cm(2) for the MEAs prepared with Pt/GCNT, Pt/CNT and Pt/C catalysts @ 0.6 V operating voltage, respectively. AST (Accelerated Stress Test) analyzes of MEAs prepared with Pt/GCNT and Pt/CNT catalysts were also performed and compared with Pt/C catalyst. According to current density @ 0.6 V after 10,000 potential cycles, Pt/GCNT, Pt/CNT and Pt/C catalysts can retain 61%, 67% and 60% of their performance, respectively. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Doctoral Thesis Yüksek Performanslı Elektrokimyasal Hidrojen Kompresörünün Deneysel Olarak Geliştirilmesi(2023) Durmuş, Gizem Nur Bulanık; Devrim, Yılser; Çolpan, Can Özgür; Mechanical Engineering; Energy Systems EngineeringElektrokimyasal hidrojen (H2) sıkıştırma (ECHC) teknolojisi, H2'nin tek bir adımda sıkıştırılması ve saflaştırılması için umut vaat etmesi nedeniyle son zamanlarda dikkatleri üzerine çekmiştir. Şu anda, H2 üretmenin en yaygın ve en ucuz yöntemi, hidrokarbonların buharla reformasyonudur. Diğer bir deyişle, doğal gaz ve kömür H2'nin en uygun kaynaklarıdır. Bununla birlikte, bu yöntemin dezavantajı, karbon monoksit (CO) ve karbon dioksit (CO2) gibi bazı safsızlıklar yaymasıdır. Bu tez kapsamında yüksek sıcaklık elektrokimyasal H2 kompresörü (HT-ECHC) geliştirilmiştir. H2'nin saflaştırılması ve sıkıştırılması ile ilgili çalışmalarda deneysel bir yöntem kullanılmıştır. ECHC sistemlerinde karşılaşılan en büyük sorunlardan biri katalizörün CO nedeniyle zehirlenmesidir. Bu durum katalizörü kullanılamaz hale getirmekte ve katalizör maliyetleri ortaya çıkmaktadır. Bu nedenle bu çalışma, CO toleransı yüksek, 140-180 °C arasında çalışan ve düşük güç tüketen bir HT-ECHC geliştirmeyi amaçlamıştır. Bu çalışmada, farklı molar oranlarda H2, CO2 ve CO içeren reformat gazlar kullanılarak PBI membran bazlı HT-ECHC'nin H2 saflaştırma ve sıkıştırma performansı incelenmiştir. Performans testlerinde sıcaklığın HT-ECHC performansı üzerindeki etkisinin en kritik faktörlerden biri olduğu vurgulanmıştır. HT-ECHC'nin performansının CO'nun molar oranının artmasıyla düştüğü gözlenmiştir. Gaz kromatografisi (GC) sonuçları, 160 °C'de >%99,99 H2 saflığının elde edildiğini göstermiştir. Sonuçlara göre H2, 1.5V sabit voltaj ile atmosferik basınçtan 60 bara başarıyla sıkıştırılmıştır.Article YÜKSEK SICAKLIK PROTON DEĞİŞİM MEMBRAN YAKIT HÜCRESİ MİKROKOJENERASYON UYGULAMASININ DENEYSEL VE TEORİK İNCELENMESİ(2018) Devrim, Yılser; Yapıcı, Ekin Özgirgin; Energy Systems EngineeringBu çalışmada, yüksek verimlilikleri ve çevre dostu teknolojiler olmaları sebebiyle tercih edilen, güvenilir güç üretim tekniklerinden biri olan yüksek sıcaklık proton değişim membran (YSPEM) yakıt hücreleri kullanılarak bir evsel mikro-kojenerasyon (birlikte ısı-güç) sistemi tasarlanmıştır. Tasarlanan sistem, YSPEM yakıt hücresi tarafından üretilen elektrik gücü ve faydalı ısının kombine bir şekilde, kullanılmasını içermektedir. Hücrenin çalışması sırasında, yüksek performans ve kararlı güç üretimi sağlanabilmesi için hücre içerisinde üretilen ısının uzaklaştırılması ve hücre içi sıcaklığın sabit kalması gerekmektedir. Bu sebeple tasarlanan yenilikçi soğutma sisteminin atık ısısı, sıcak su ısıtmasında kullanılacak olan ısıl enerjinin teminini sağlamaktadır. Böylelikle toplam verim basit çevrimlere göre yaklaşık iki katına çıkabilmektedir. Çalışma kapsamında tasarlanan 225 W gücünde YSPEM yığını 160°C çalışma sıcaklığında hidrojen ve hava gazları ile test edilmiştir. Çalışması sırasında sıcaklığın hücre içerisinde homojen olarak dağılımı, hücrenin kısa sürede gerekli çalışma sıcaklığına ulaşabilmesi, yakıt hücresinde oluşan ısının hücreden sürekli olarak uzaklaştırılabilmesi için yakıt hücresi yığını soğutucu akışkan (Isı Transfer Yağı 32-Petrol Ofisi) kullanılarak soğutulmuştur. Hücre izolasyon malzemesi seçimi ve kalınlığı, doğal taşınım ve radyasyon yolu ile ısı kaybı hesabıyla belirlenmiştir. Maksimum verim çalışma koşulları için mikro-kojenerasyon sisteminin su giriş çıkış sıcaklıkları, su ve soğutucu akışkan debileri, uygun boru çapı hesabı ve pompa güç hesabı yapılarak nihai sistem tasarlanmıştır. Çalışmada tasarlanan kojenerasyon sisteminde, YSPEM yığınının soğutulması ile açığa çıkan atık ısı, 15-20C’lik şebeke suyunun ısıtılması için kullanılmıştır. Şebeke suyu sıcaklığı yalıtımlı hücre kullanılması durumunda ortalama 50C’ye kadar ısıtılmıştır. Elde edilen veriler yakıt hücresi mikro-kojenerasyon uygulamasının kullanılabilirliğini göstermektedir.
