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COAR Access Rights: metadata only accessInstitution Author: Devrim, Yılser

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Now showing 1 - 3 of 3
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    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 Engineering
    In 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.
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    Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Performance Assessment of Anion Exchange Electrolyzer With PBI-BASED Membrane Through 0-D Modeling
    (Elsevier Ltd, 2025) Celebi, Ceren; Colpan, C. Ozgur; Devrim, Yilser
    Anion exchange membrane (AEM) water electrolysis is emerging as a promising method for the sustainable production of hydrogen. A key advantage lies in the potential for cost-effective hydrogen production by substituting expensive noble metal electrocatalysts with affordable transition metals. This work presents a 0-D mathematical model for evaluating the performance of AEMWEs, with a particular focus on polybenzimidazole (PBI)-based membranes, which are renowned for their high thermal stability, chemical resistance and excellent conductivity in alkaline media. The objective of the model is to predict the behavior of membranes in AEMWE systems, and it has been employed to evaluate the performance of a range of PBI membranes. To ensure precision, the values were meticulously selected from the literature, in accordance with the experimental conditions. Furthermore, IR-corrected validation was incorporated to isolate the impact of membrane conductivity on performance, thereby facilitating a dependable assessment of PBI membranes under diverse conditions. The model considers the effects of electrolyte resistance and bubble formation on cell voltage behavior. The efficiency was evaluated on the basis of the higher heating value (HHV). The findings demonstrate that one membrane exhibits consistent efficiency across a broad temperature range (40-90 degrees C), whereas the other displays notable variability under diverse conditions. In particular, the efficiency of the electrolyzer is significantly enhanced by the use of thinner membranes and higher temperatures. The highest efficiencies obtained were 83.9% and 79.8% for 25 mu m and 50 mu m PBI/Polystyrene membrane under the operating conditions of 1 M KOH solution at 80 degrees C and current density of 2 A/cm2. This study aims to provide valuable information on the performance of PBI membranes through a zero-dimensional model validated by experimental data.
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    Article
    Citation - WoS: 8
    Citation - Scopus: 8
    Polyethyleneimine Functionalized Waste Tissue Paper@waste PET Composite for the Effective Adsorption and Filtration of Organic Dyes From Wastewater
    (Elsevier B.V., 2025) Radoor, Sabarish; Karayil, Jasila; Devrim, Yilser; Kim, Hern
    This study explores the potential of repurposing discarded plastic bottles and cellulosic paper waste to develop cost-effective and high-performance composites for dye removal applications. A novel composite, polyethyleneimine (PEI)-functionalized waste tissue integrated into waste polyethylene terephthalate (wPET) (PEIWT/wPET), was designed as an environmentally friendly adsorbent for wastewater treatment. Successful surface functionalization with PEI was confirmed through FTIR, EDX, and XPS analyses. The PEI-modified composite exhibited enhanced mechanical and thermal stability while demonstrating significantly improved dye adsorption/filtration performance. The composite was evaluated for the removal of both cationic (crystal violet, CV) and anionic (orange II, O II) dyes under optimized conditions; (10,000 mg/L and 1666 mg/L) adsorbent dosage, (11 and 1) pH, 10 mg/L initial dye concentration, and (180 min and 120 min) contact time for CV and O II respectively. Experimental results showed that PEIWT/wPET achieved maximum adsorption capacities of 3.94 mg/g for CV and 11.73 mg/g for O II, approximately five times higher than the unmodified composite (0.74 and 2.4 mg/g). Adsorption isotherm and kinetic studies indicated that the data aligned well with the Langmuir as well as Freundlich and pseudo-second order models. The membrane also exhibited filtration capability for both dyes, achieving a filtration efficiency of 78.69 % for anionic and 41.31 % for cationic dye separation. Overall, the PEIWT/wPET composite offers a promising, sustainable, and energy-efficient solution for the removal of organic pollutants.