Devrim, Yılser
Loading...
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
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
Scopus Author ID
Turkish CoHE Profile ID
Google Scholar ID
WoS Researcher ID
Scholarly Output
77
Articles
50
Citation Count
2249
Supervised Theses
9
77 results
Scholarly Output Search Results
Now showing 1 - 10 of 77
Article Citation Count: 21Reliability based modeling of hybrid solar/wind power system for long term performance assessment(Elsevier Sci Ltd, 2021) Eryilmaz, Serkan; Eryılmaz, Serkan; Bulanik, Irem; Devrim, Yılser; Industrial Engineering; Energy Systems EngineeringThis paper is concerned with reliability based long-term performance assessment of hybrid solar/wind power system. In particular, an analytical expression is obtained for the theoretical distribution of the power output of the hybrid system by taking into account the reliability values of renewable energy components. An expression for the expected energy not supplied (EENS) is also derived and used to compute the energy index of reliability (EIR) that is directly related to EENS. Because the derived expressions involve reliability values which are related to mechanical states of the renewable energy components, the results enable us to evaluate properly the performance of the hybrid system. A numerical example is included to illustrate the results.Conference Object Citation Count: 47Energy and exergy performance assessments of a high temperature-proton exchange membrane fuel cell based integrated cogeneration system(Pergamon-elsevier Science Ltd, 2020) Devrim, Yılser; Colpan, C. Ozgur; Devrim, Yilser; Energy Systems EngineeringHigh-temperature proton exchange membrane fuel cell (HT-PEMFC), which operates between 160 degrees C and 200 degrees C, is considered to be a promising technology, especially for cogeneration applications. In this study, a mathematical model of a natural gas fed integrated energy system based on HT-PEMFC is first developed using the principles of electrochemistry and thermodynamics (including energy and exergy analyses). The effects of some key operating parameters (e.g., steam-to-carbon ratio, HT-PEMFC operating temperature, and anode stoichiometric ratio) on the system performance (electrical, cogeneration, and exergetic efficiencies) are examined. The exergy destruction rates of each component in the integrated system are found for different values of these parameters. The results show that the most influential parameter which affects the performance of the integrated system is the anode stoichiometric ratio. For the baseline conditions, when the anode stoichiometric ratio increases from 1.2 to 2, the electrical, cogeneration, and exergetic efficiencies decrease by 42.04%, 33.15%, and 37.39%, respectively. The highest electrical power output of the system is obtained when the SCR, operating temperature, and anode stoichiometric ratio are taken as 2, 160 degrees C, and 1.2, respectively. For this case, the electrical, cogeneration, and exergetic efficiencies are found as 26.20%, 70.34%, and 26.74%, respectively. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Article Citation Count: 21Preparation of polybenzimidazole/ZIF-8 and polybenzimidazole/UiO-66 composite membranes with enhanced proton conductivity(Pergamon-elsevier Science Ltd, 2022) Devrim, Yılser; Ozkan, Necati; Devrim, Yilser; Energy Systems EngineeringMetal-organic frameworks (MOFs) are considered emerging materials as they further improve the various properties of polymer membranes used in energy applications, ranging from electrochemical storage and purification of hydrogen to proton exchange membrane fuel cells. Herein, we fabricate composite membranes consisting of polybenzimidazole (PBI) polymer as a matrix and MOFs as filler. Synthesis of ZIF-8 and UiO-66 MOFs are conducted through a typical solvothermal method, and composite membranes are fabricated with different MOF compositions (e.g., 2.5, 5.0, 7.5, and 10.0 wt %). We report a significant improvement in proton conductivity compared with the pristine PBI; for example, more than a three-fold increase in conductivity is observed when the PBI-UiO66 (10.0 wt %) and PBI-ZIF8 (10.0 wt %) membranes are tested at 160 degrees C. Proton conductivities of the composite membranes vary between 0.225 and 0.316 S cm(-1) at 140 and 160 degrees C. For the comparison, pure PBI exhibits 0.060 S cm(-1) at 140 degrees C and 0.083 S cm(-1) at 160 degrees C. However, we also report a decrease in permeability and mechanical stability with the composite membranes. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Conference Object Citation Count: 0Optimization of modeling parameters of of a direct dimethyl ether fuel cell (DDMEFC)(Institute of Electrical and Electronics Engineers Inc., 2019) Devrim, Yılser; Ozgur Colpan,C.; Devrim,Y.; 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. © 2019 University of Split, FESB.Article Citation Count: 65Investigation of Nafion based composite membranes on the performance of DMFCs(Pergamon-elsevier Science Ltd, 2017) Devrim, Yılser; Ozden, Adnan; Devrim, Yilser; Colpan, C. Ozgur; Energy Systems EngineeringIn this study, Direct Methanol Fuel Cells (DMFCs) based on composite membranes (Nafion/ SiO2 and Nafion/TiO2) were manufactured; and their performances were compared with that of the DMFC based on Nafion (R) 115 membrane. For this purpose, composite membranes were synthesized applying the recasting method with the inorganic particle loading of 2.5 wt%. The structures of these composite membranes were investigated by Scanning Electron Microscopy (SEM), proton conductivity measurement and water uptake measurement. Ultrasonic coating technique was used in the manufacturing of the Membrane Electrode Assemblies (MEAs). The performance tests of the composite membranes were conducted using in-house experiments. In these tests, the effect of methanol concentration (0.75, 1, and 1.5 M) on the performance of the MEA having Nafion 115 was investigated at 80 degrees C to find the value of the methanol concentration that yields the highest power density. This study showed that the MEA operating at 1 M gives the highest performance. Then, the performance of this MEA was compared with that of the MEAs having Nafion/ SiO2 and Nafion/TiO2 composite membranes in single cell DMFC setup at 60 degrees C, 80 degrees C, and 95 degrees C. The results of these experiments demonstrated that the MEA having Nafion/TiO2 composite membrane provides much better performance with the maximum power density values of 422.04 W/m(2), 641.16 W/m(2), and 710.88 W/m(2) at 60 degrees C, 80 degrees C, and 95 degrees C, respectively. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Article Citation Count: 153Development of polybenzimidazole/graphene oxide composite membranes for high temperature PEM fuel cells(Pergamon-elsevier Science Ltd, 2017) Devrim, Yılser; Pehlivanoglu, Kubra; Ozdemir, Yagmur; Devrim, Yilser; Energy Systems EngineeringIn this study, phosphoric acid doped Polybenzimidazole/Graphene Oxide (PBI/GO) nano composite membranes were prepared by dispersion of various amounts of GO in PBI polymer matrix followed by phosphoric acid doping for high temperature proton exchange membrane fuel cell (HT-PEMFC) application. The structure of the PBI/GO composite membranes was investigated by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and by thermogravimetric analysis (TGA). The introduction of GO into the FBI polymer matrix helps to improve the acid doping, proton conductivity and acid leaching properties. The SEM analyses have proved the uniform and homogeneous distribution of GO in composite membranes. The composite membranes were tested in a single HT-PEMFC with a 5 cm(2) active area at 165 degrees C without humidification. HT-PEMFC tests show that PBI/ GO composite membrane with 2 wt. % GO content performed better than bare PBI membrane at non humidified condition. At ambient pressure and 165 degrees C, the maximum power density of the PBI/GO-1 membrane can reach 0.38 W/cm(2), and the current density at 0.6 V is up to 0.252 A/cm(2), with H-2/air. The results indicate the PBI/GO composite membranes could be utilized as the proton exchange membranes for HT-PEMFC. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Doctoral Thesis PEM yakıt pili hibrit malzemesi üzerinde desteklenen platin içerli elektrokatalizörlerin geliştirilmesi(2023) Devrim, Yılser; Devrim, Yılser; Yaman, Şeniz Özalp; Energy Systems EngineeringDünyada artan enerji talebi, alternatif enerji teknolojilerine olan ihtiyacı artırmıştır. Önemli bir alternatif enerji kaynağı olan hidrojeni kullanan yakıt pilleri son yıllarda büyük ilgi görmektedir. Yakıt pili türleri arasında proton değişim membranlı yakıt pilleri (PEMFC), modüler yapıları, yüksek verimleri ve düşük çalışma sıcaklıkları nedeniyle en ilgi çekici yakıt pili türüdür. Özellikle komponent geliştirme çalışmaları PEMFC'lerin performansını artırmaya yönelik olarak dikkat çekmektedir. Bu tez çalışmasında, çok duvarlı karbon nanotüp-grafen MWCNT destekli Pt katalizörleri, PEMFC performansını araştırma yöntemini incelemek için mikrodalga destekli yaklaşım kullanılarak sentezlenmiştir. Başlangıç maddesi olarak [(NH4)2[Pt2(HPO4)4(H2O)2] (Ptcomplex-1) ve [(NH4)2[Pt2(SO4)4(H2O)2] (Ptcomplex-2) kullanılarak PEMFC uygulaması için MWCNT destekli platin katalizörler hazırlanmıştır. Katalizörlerin mikro yapısını ve morfolojisini incelemek için TGA, XRD, HR-TEM ve XPS analizleri uygulanmıştır. Hazırlanan katalizörlerden Ptcomplex-1/MWCNT-3 ve Ptcomplex-2/MWCNT-3 60-80 °C aralığında H2/hava ile PEMFC içinde test edilmiştir. Ptcomplex-1/MWCNT-3 katalizörü kullanılarak hazırlanan bir membran elektrot atacı (MEA) için 60, 65, 70 ve 80 ⁰C'de elde edile maksimum güç yoğunluğu değerleri sırasıyla 0.36, 0.39, 0.41 ve 0.26 W/cm2 ve Ptcomplex-2/MWCNT-3 katalizörü için ise 0.38, 0.423, 0.44 ve 0.28 W/cm2 olarak belirlenmiştir. Elde edilen sonuçlara göre Ptcomplex/MWCNT katalizörlerinin Pt/C katalizörüne göre daha iyi PEMFC performansı gösterdiği belirlenmiştir. Hazırlanan katalizörlerle gelecekte yapılacak MEA optimizasyon çalışmaları ile katalizörlerin performansları daha da iyileştirilebilir.Article Citation Count: 17Theoretical derivation of wind plant power distribution with the consideration of wind turbine reliability(Elsevier Sci Ltd, 2019) Eryilmaz, Serkan; Eryılmaz, Serkan; Devrim, Yilser; Devrim, Yılser; Industrial Engineering; Energy Systems EngineeringThe wind power generated by a wind plant has a stochastic nature due to randomness in the wind speed. Although the empirical distribution of the wind power has been extensively studied by using data sets in different regions, several works focused on theoretical distribution of the wind power produced by wind turbines. In this paper, the theoretical distribution of the wind plant power is obtained. In the derivation of the distribution of the wind plant power, wind turbine reliability is taken into account. The wind plant power distribution can be effectively used if the wind speed probability distribution is known. Theoretical results are illustrated for Weibull and Bimbaum-Saunders wind speed distributions which have been found to be suitable for real data collected at two different locations.Master Thesis Güneş esaslı hibrit güç sistemlerinin tasarımı ve optimizasyonu(2020) Ceylan, Ceren; Devrim, Yılser; Devrim, Yılser; Energy Systems EngineeringGelişen teknoloji ve artan Dünya nüfusuyla birlikte enerji talebi de artmaktadır. Fosil yakıtların günden güne tükenmesi nedeniyle, temiz enerji üretmek için yenilenebilir enerji kaynaklarını kullanılmaya başlanmıştır. En çok tercih edilen yenilenebilir enerji kaynağı olan güneş enerjisi bulutlu günlerde ve gecelerde kullanılamaz. Ayrıca güneş enerjisinin en büyük dezavantajı depolanma sorunun olmasıdır. Bu şartlarda enerji ihtiyacını karşılamak ve sürekliliği sağlamak için yakıt pilleri kullanılır. Kısa başlangıç sürelerinin olması ve yüksek verimlilikleri nedeniyle yakıt pilleri popüler hale geldi. Evrende en çok bulunan element olan Hidrojen (H2), yakıt pillerinde yakıt olarak kullanılır. H2 enerji kaynağı değildir ancak çok iyi bir enerji taşıyıcısıdır. Yakıt olarak kullanıldığında su ya da su buharı ortaya çıkar. Enerji üretimi sırasında, çevreyi kirleten ve sera etkisini arttıran kimyasallar ve zararlı gazlar yoktur ve bu da çevre dostu olduğunu kanıtlar. Bu tez çalışmasında, Şanlıurfa'da bulunan bir seranın enerji ihtiyacını karşılamak için günde 5 saat çalıştırılacak olan 2.4 kW Proton Değişim Membran Yakıt Pili (PEMFC) tasarlanmıştır. PEMFC'nin gereksinimi olan H2'yi üretmek için elektrolizör dizayn edilmiş ve elektrolizörün çalışması için gerekli olan elektrik 80 adet fotovoltaik (PV) modülden sağlanmıştır. Sistemde üretilen H2 PEMFC'de kullanılmak üzere tanklarda depolanır. Tasarlanan sistemde bir yılın sonunda toplam 430 kg H2 depolanmıştır. Bunun yanı sıra PEMFC çalışırken ısı ortaya çıkar ve bir günlük çalışmada yaklaşık olarak 20 kW ısı üretilmektedir. Bu ısı PEMFC'nin güvenliği ve yüksek verimliliğin sağlanması için uzaklaştırılmalıdır. Tasarlanan sistemde PEMFC tarafından üretilen ısı bir ısı değiştiricisi yardımıyla uzaklaştırılmaktadır. Bu işlemde ısı uzaklaştırılması ile ısınan PEMFC soğutma suyunun sıcaklığı 34 oC'ye kadar düşerken, seranın ısınması için kullanılacak suyun ısısını 61 oC'ye kadar çıkarılmıştır. Yatırım, işletme ve bakım maliyetinin, hibrit enerji sisteminin çalışma süresince ürettiği enerji miktarına oranı seviyelendirilmiş enerji maliyetini verir. Bu sisteminin seviyelendirilmiş enerji maliyeti 1.77 $/kWh olarak hesaplanmıştır.Article Citation Count: 0Statistics and probability theory in renewable energy: Teaching and research(Wiley, 2023) Eryilmaz, Serkan; Eryılmaz, Serkan; Kateri, Maria; Devrim, Yılser; Industrial Engineering; Energy Systems EngineeringIn this paper, the key-role and utility of statistics and probability theory in the field of renewable energy are emphasized and illustrated via specific examples. It is demonstrated that renewable energy is a very suitable field to effectively teach and implement many statistical and probabilistic concepts and techniques. From a research point of view, statistical and probabilistic methods have been successfully employed in evaluating renewable energy systems. These methods will continue to be of core interest for the renewable energy sector in the future, as new and more complex renewable energy systems are developed and installed. In this context, some future research directions in relation to the evaluation of renewable energy systems are also presented.
