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Article Citation - WoS: 52Citation - Scopus: 60Comparative Study of Pv/Pem Fuel Cell Hybrid Energy System Based on Methanol and Water Electrolysis(Pergamon-elsevier Science Ltd, 2019) Budak, Yagmur; Devrim, YilserIn this study, we investigated the comparative analysis of a solar-fuel cell hybrid system based on water and methanol electrolysis. The proposed system comprises PV, electrolyzer and proton exchange membrane fuel cell (PEMFC). The hybrid system is designed to supply the hydrogen (H-2) needed of the PEMFC system and also to fulfill the H-2 requirement of other applications. The actual data of solar irradiation of Izmir, Turkey are used in the simulation. The methanol and water electrolyzers were designed for 1.2 kW PEMFC H-2 demand which were met a house-hold energy requirement. Analyzes show that the use of the methanol electrolyzer can produce 27% more H-2 than the water electrolyzer. According to the study, it was determined that the methanol-based hybrid system offered a viable option for self-sustaining in household application.Conference Object Optimization of modeling parameters of of a direct dimethyl ether fuel cell (DDMEFC)(Ieee, 2019) Alpaydin, Guvenc Umur; Colpan, C. Ozgur; Devrim, YilserDirect 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.Article Citation - WoS: 17Citation - Scopus: 18Optimal Design and Technoeconomic Analysis of On-Site Hydrogen Refueling Station Powered by Wind and Solar Photovoltaic Hybrid Energy Systems(Pergamon-elsevier Science Ltd, 2025) Ozturk, Reyhan Atabay; Devrim, YilserIn this study, a grid-connected on-site hydrogen filling station (HRS) integrated with renewable energy systems is designed and examined for different daily hydrogen refueling capacities. The installation location of the HRS is selected in Izmir (Turkey) and daily solar radiation and wind speed data are used in the calculations. The HRS station was integrated with a hybrid energy system using photovoltaic panels (PV), wind turbine (WT) and PV/ WT and five different daily refueling scenarios were investigated. A techno-economic analysis is conducted for the designed HRS system, considering the initial investment capital, installation and operating costs. The levelized cost of hydrogen (LCOH) is evaluated according to different refueling capacity scenarios, periods of operation and renewable energy installation capacities. The lowest LCOH is obtained as 4.5 /kg H2 in the PVintegrated HRS system for a 20-year investment scenario. The results prove the suitability of the HRS system for integrating renewable energy in the identified region. It is recommended to integrate analytical models for the system components to increase the reliability of the design and optimization process in future planned studies.Conference Object Citation - WoS: 98Citation - Scopus: 102Experimental Investigation of Co Tolerance in High Temperature Pem Fuel Cells(Pergamon-elsevier Science Ltd, 2018) Devrim, Yilser; Albostan, Ayhan; Devrim, HuseyinIn 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: 137Citation - Scopus: 149Polybenzimidazole/Sio2< Hybrid Membranes for High Temperature Proton Exchange Membrane Fuel Cells(Pergamon-elsevier Science Ltd, 2016) Devrim, Yilser; Devrim, Huseyin; Eroglu, InciPolybenzimidazole/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.Article Citation - WoS: 5Citation - Scopus: 5Performance 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, YilserIn 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.Article Citation - WoS: 9Citation - Scopus: 10Investigation 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; 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 Mathematical Modeling of a Direct Dimethyl Ether Fuel Cell(Wiley-hindawi, 2022) Alpaydin, Guvenc Umur; Durmus, Gizem Nur Bulanik; Colpan, C. Ozgur; Devrim, YilserIn 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.Article Citation - WoS: 45Citation - Scopus: 46Carbon Nanotube-Graphene Supported Bimetallic Electrocatalyst for Direct Borohydride Hydrogen Peroxide Fuel Cells(Pergamon-elsevier Science Ltd, 2021) Uzundurukan, Arife; Akca, Elif Seda; Budak, Yagmur; Devrim, YilserAt present study, carbon nanotube-graphene (CNT-G) supported PtAu, Au and Pt catalysts were prepared by microwave-assisted synthesis method to investigate the direct liquid-fed sodium borohydride/hydrogen peroxide (NaBH4/H2O2) fuel cell performance. Prepared catalysts were characterized by TGA, XRD, TEM, ICP-OES, cyclic voltammetry and rotating disc electrode (RDE) voltammetry. The catalysts were tested in a single NaBH4/H2O2 fuel cell with 25 cm(2) active area to evaluate fuel cell performance. The effects of temperature and fuel concentration on fuel cell performance were examined to observed best operating conditions. As a result of direct NaBH4/H2O2 fuel cell experiments, maximum power densities of 139 mW/cm(2), 125 mW/cm(2) and 113 mW/cm(2) were obtained for PtAu/CNT-G, Au/CNT-G and Pt/CNT-G catalysts, respectively. PtAu/CNT-G catalyst showed the enhanced NaBH4/H2O2 fuel cell performance, which was higher than the Pt/CNT-G catalyst and Au/CNT-G catalyst at 50 degrees C. The enhanced NaBH4/H2O2 performance can be attributed to synergistic effects between Pt and Au particles on CNT-G support providing a better catalyst utilization and interaction. These results suggest that the prepared PtAu/CNT-G catalyst is a promising anode catalyst for NaBH4/H2O2 fuel cell application. (c) 2020 Elsevier Ltd. All rights reserved.Article Experimental Study and Theoretical Investigation of High Temperature Proton Exchange Membrane Fuel Cell Micro-Cogeneration Application(Turkish Soc thermal Sciences Technology, 2018) Devrim, Yilser; Ozgirgin Yapici, Ekin; Energy Systems EngineeringIn this study, a house hold micro-cogeneration system is designed using high temperature proton exchange membrane (HTPEM) fuel cell. HTPEM type fuel cells gain the highest interest lately, due to their advantages in terms of increasing efficiency and power quality, reducing harmful emissions and flexibility of operation with respect to the other fuels. The micro-cogeneration system involves producing both electrical energy and hot water and/or vapor together in an economical way, utilizing single fuel (HTPEM fuel cells) for household applications. During the operation of the fuel cell, for high efficiency and stable power production, the access heat of the stack should be removed constantly and the temperature of the stack should be held stable. Heat recovered from the designed innovative cooling system is used for acquiring energy for heating water. This way, thermal efficiency is almost doubled compared to simple cycle. In the scope of this study, 225 W HTPEM fuel cell stack is designed and tested at 160 degrees C operation temperature with hydrogen gas and air. During operation, for homogenous distribution of temperature among the cells, for a short start up period leading to a fast required steady state temperature and for constantly removing the access heat produced in the cell, the cell stack is cooled by using a cooling fluid (Heat Transfer Oil 32- Petrol Ofisi). Selection of insulation material type and thickness for the cell stack is done using natural convection and radiation loss calculations. For the most efficient operating conditions, micro-cogeneration system water inlet and exit temperatures, water and cooling fluid flow rates, convenient pipe diameter and pump power calculations are done to finalize the design. With the cogeneration system designed during the studies, by recovering the access heat of the insulated HTPEM cell stack, district water with initial temperature of 15-20 degrees C is heated around 50 degrees C. Data gathered during studies indicate that fuel cell micro-cogeneration application is highly viable.
