Durmuş, Gizem Nur Bulanık
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Name Variants
D., Gizem Nur Bulanik
Durmus, Gizem Nur Bulanik
G., Durmus
D., Gizem Nur Bulanık
G. N. B. Durmus
Gizem Nur Bulanik, Durmus
G.N.B.Durmus
Durmus G.
Gizem Nur Bulanık, Durmuş
Durmus,G.N.B.
G. N. B. Durmuş
Durmuş, Gizem Nur Bulanık
Durmuş,G.N.B.
G.,Durmuş
D.,Gizem Nur Bulanık
G.N.B.Durmuş
D.,Gizem Nur Bulanik
Durmus, Gizem Nur Bulanik
G., Durmus
D., Gizem Nur Bulanık
G. N. B. Durmus
Gizem Nur Bulanik, Durmus
G.N.B.Durmus
Durmus G.
Gizem Nur Bulanık, Durmuş
Durmus,G.N.B.
G. N. B. Durmuş
Durmuş, Gizem Nur Bulanık
Durmuş,G.N.B.
G.,Durmuş
D.,Gizem Nur Bulanık
G.N.B.Durmuş
D.,Gizem Nur Bulanik
Job Title
Doktor Öğretim Üyesi
Email Address
gizem.bulanik@atilim.edu.tr
ORCID ID
Scopus Author ID
Turkish CoHE Profile ID
Google Scholar ID
WoS Researcher ID
Scholarly Output
9
Articles
6
Citation Count
96
Supervised Theses
2
9 results
Scholarly Output Search Results
Now showing 1 - 9 of 9
Master Thesis Mikro invertorlü ve dizi invertörlü fotovoltaik sistemlerin modellenmesi ve karşılştırılması(2019) Durmuş, Gizem Nur Bulanık; Aslan, Özgür; Aslan, Özgür; Mechanical EngineeringFotovoltaik paneller, güneş enerjisini seri ve paralel bağlanmış fotovoltaik hücreler vasıtasıyla doğrudan elektrik enerjisine dönüştüren yapılardır. Fotovoltaik panel verimliliğini negatif yönde etkileyen birkaç neden vardır. Panelin üzerine düşen geçici veya sürekli gölgeleme, panel veriminin düşmesinin sebeplerinden bir tanesidir. Paneller, bulutlar, binalar, toz, kuş veya yaprak gibi engeller nedeniyle gölgelenmeye maruz kalabilir.Ek olarak, sürekli gölgeleme sıcak nokta etkisi yaratır. Bu durum uzun vadede panelde veya panel grubunda arızalara neden olmaktadır. Sistemlerde ortaya çıkan bir diğer problem, fotovoltaik panellerin birbirine bağlanması noktasında ortaya çıkar. Fotovoltaik paneller, özellikle büyük ölçekli fotovoltaik sistemlerde seri olarak bağlanır. Seri bağlı paneller çok yüksek gerilimlere ulaşır ve yüksek gerilime dayalı problemler ortaya çıkabilir. Dizi invertörün kullanıldığı fotovoltaik sistemlerde, fotovoltaik paneller sınırlı şekillerde yerleştirilebilir. Bunun karşısında, mikro invertörler panel tabanlı sistemlerdir ve kurulumu kolaydır. Panelleri invertöre göre yerleştirmeye gerek yoktur. Mikro invertörler, genellikle küçük ölçekli fotovoltaik sistemler için tercih edilse de, bazı durumlarda büyük ölçekli fotovoltaik sistemlerde de kullanılır. Her panel kendi AC gücünü ürettiğinden, yüksek voltaj sorunu ortadan kalkar. Fakat yüksek maliyetleri ve dizi invertörlere göre daha düşük olan verimleri nedeniyle büyük ölçekli tesislerde tercih edilmemektedir. Bu tez çalışmasında, bu problemler göz önüne alınarak, Ankara İlinde 24 kWp kurulu güce sahip fotovoltaik bir sistemin, üç farklı gölge yoğunluğunda hem dizi invertör hem de mikro invertör ile bir paket program yardımıyla simülasyonları yapılmıştır. Yapılan simülasyon raporları doğrultusunda sistemler karşılaştırılmıştır.Review Citation Count: 42A review on the development of the electrochemical hydrogen compressors(Elsevier, 2021) Durmuş, Gizem Nur Bulanık; Colpan, C. Ozgur; Devrim, Yılser; Mechanical Engineering; Energy Systems EngineeringHydrogen should be stored at high pressure and high purity, especially when utilized in fuel cells. Conventionally, mechanical compressors are used for pressurization of hydrogen; however, this technology has disadvantages such as noise and vibration during operation due to their moving parts. Electrochemical hydrogen compressors (ECHC) have emerged as an alternative solution, as these devices can purify and compress hydrogen electrochemically in a single device. This review provides a comprehensive overview of key components and management strategies of the ECHC systems. This review will also provide an overview of different hydrogen compression technologies and provides a comprehensive overview of the latest developments and current issues and future of ECHCs. For this purpose, firstly, the advantages and disadvantages of ECHC compared to mechanical compressors are explained. Then, recent studies on hydrogen purification methods are given. The working principle of ECHC, material development studies and mathematical modeling of ECHCs are also discussed.Article Citation Count: 5Investigation of the performance of high-temperature electrochemical hydrogen purification from reformate gases(Wiley, 2022) Durmuş, Gizem Nur Bulanık; Colpan, C. Ozgur; Devrim, Yılser; Mechanical Engineering; Energy Systems EngineeringIn 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.Article Citation Count: 0Mathematical modeling of a direct dimethyl ether fuel cell(Wiley-hindawi, 2022) Durmuş, Gizem Nur Bulanık; Durmus, Gizem Nur Bulanik; Devrim, Yılser; Devrim, Yilser; Mechanical Engineering; Energy Systems EngineeringIn this study, a mathematical model of a direct dimethyl ether fuel cell (DDMEFC) is developed to examine the effect of operating conditions on voltage losses and cell performance. In modeling, the electrochemical relations and mass balances are used to find the cell voltage for the given conditions. The values of some modeling parameters are determined using experimental data through curve fitting. For validation purposes, in-house experimental studies are conducted. For this purpose, Pt50Ru25Pd25/C, Pt40Ru40Pd20/C, and Pt50Pd50/C anode catalysts are synthesized by the microwave method. The effects of these synthesized catalysts and the operating conditions (cell temperature, the molar ratio of dimethyl ether, and water) on the DDMEFC performance are discussed by comparing the activation and ohmic polarization as well as the polarization curves using the model developed. This cell-level modeling approach could be considered as a preliminary step in the design process of a DDMEFC stack.Doctoral Thesis Yüksek performanslı elektrokimyasal hidrojen kompresörünün deneysel olarak geliştirilmesi(2023) Durmuş, Gizem Nur Bulanık; Devrim, Yılser; 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 Citation Count: 1Fabrication and performance evaluation of graphene-supported PtRu electrocatalyst for high-temperature electrochemical hydrogen purification(Pergamon-elsevier Science Ltd, 2023) Durmuş, Gizem Nur Bulanık; Durmus, Gizem Nur Bulanik; Devrim, Yılser; Mechanical Engineering; Energy Systems EngineeringThe main aim of this study is to investigate the high-temperature electrochemical hydrogen purification (HT-ECHP) performances of graphene nanoplatelet (GNP) support material decorated with platinum (Pt) and platinum-ruthenium (PtRu) nanoparticles prepared by microwave irradiation technique. Prepared catalysts coupled to the phosphoric acid doped polybenzimidazole (PBI) membrane for HT-ECHP application. The structural and electrochemical properties of the catalysts were examined by thermogravimetric analysis (TGA), X-Ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transition electron microscopy (TEM) and cyclic voltammetry (CV) analyses. The characterization results indicate that the catalysts provided the necessary properties for HT-ECHP application. The HT-ECHP performances are investigated with reformate gas mixture containing hydrogen (H2), carbon dioxide (CO2) and carbon monoxide (CO) in the range of 140-180 & DEG;C. The results show that the electrochemical purification performances of the catalysts increase with increasing operating temperature. The highest H2 purification performance is obtained with PtRu/GNP catalyst. The high electrochemical H2 purification performance of the PtRu/GNP catalyst can be attributed to the strong synergistic interactions between Pt and Ru particles decorated on the GNP. These results advocate that the PtRu/GNP catalyst is a hopeful catalyst for HT-ECHP application. & COPY; 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Article Citation Count: 2Experimental and modeling studies of a high-temperature electrochemical hydrogen compressor(Pergamon-elsevier Science Ltd, 2024) Durmuş, Gizem Nur Bulanık; Kuzu, Cemil; Devrim, Yılser; Colpan, C. Ozgur; Mechanical Engineering; Energy Systems EngineeringSome non-technical factors such as economics and logistics prevent hydrogen (H2) tech-nologies from becoming more widespread in daily life. Today, the prevalence of H2 tech-nologies requires new technological developments. Electrochemical hydrogen compressors (ECHC) are of great interest due to their ability to pressurize and purify in one step. In this study, the electrochemical H2 compression performance of high phosphoric acid (PA) doped poly 2,2-m-phenylene-5,5-benzimidazole (PBI) membrane-based HT-ECHC under high temperature and non-humid conditions was investigated through both an experimental and a numerical approach. The H2 compression capacity of HT-ECHC at different operating voltages was examined by performance tests at 160 degrees C, and it was determined that the electrochemical compression performance increased with increasing operating voltage. It was observed that the current density values also increased with increasing voltage, and it was determined that a current density of 61.2 A was obtained at 1 V. As a result of the tests, H2 was successfully compressed from atmospheric pressure to 60 bar by HT-ECHC without any gas leakage. The results of the developed model were compared with the experimental performance test data, and the variation of molar flow, cell voltage, and cell efficiency over time was examined. It has been determined that the back diffusion from the cathode to the anode in the cell increases with the increasing operating voltage of HT-ECHC and therefore the cell efficiency decreases. It has been evaluated that the developed model and experimental results are in good agreement. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Article Citation Count: 43Composite membrane by incorporating sulfonated graphene oxide in polybenzimidazole for high temperature proton exchange membrane fuel cells(Pergamon-elsevier Science Ltd, 2022) Durmuş, Gizem Nur Bulanık; Durmus, Gizem Nur Bulanik; Devrim, Yılser; Mechanical Engineering; Energy Systems EngineeringThe 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.Article Citation Count: 3High-temperature electrochemical hydrogen separation from reformate gases using PBI/MOF composite membrane(Pergamon-elsevier Science Ltd, 2023) Durmuş, Gizem Nur Bulanık; Eren, Enis Oguzhan; Devrim, Yılser; Colpan, C. Ozgur; Ozkan, Necati; Mechanical Engineering; Energy Systems EngineeringIn this paper, the high-temperature electrochemical Hydrogen (H2) purification perfor-mance of a polybenzimidazole/UIO-66 metal-organic framework (PBI/UIO-66) membrane is investigated and analyzed at different values of current, temperature, and reformate feed composition. Purification measurements show that a significant reduction in gas impu-rities can be obtained. In the performance tests, three different ratios of reformate gas (RG) (H2:carbon dioxide (CO2):carbon monoxide (CO)) as RG-1= (75:25:0), RG-2= (75:22:3), and RG-3= (95:0:5) were used. The highest purification values were observed at 160 & DEG;C as 99.999%, 99.931%, and 99.708% for RG-1, RG-2, and RG-3, respectively. The obtained results show that an electrochemical H2 purification (ECHP) based on PBI/UIO-66 composite membrane is promising for H2 purification.& COPY; 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
