Browsing by Author "Calisan, Atalay"

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Citation - WoS: 31
Citation - Scopus: 33
Energy and exergy analysis of a PV-T integrated ethanol PEM electrolyzer
(Elsevier Ltd, 2021) Başar Ca̧ǧlar; Mustafa Araz; Huseyin Gunhan Ozcan; Atalay Calisan; A. Hepbasli; Ozcan, Huseyin Gunhan; Calisan, Atalay; Araz, Mustafa; Hepbasli, Arif; Caglar, Basar
A photovoltaic-thermal (PV-T) integrated ethanol proton exchange membrane electrolyzer (PEME) was proposed as a low-energy consuming energy storage option for renewable-sourced electricity as well as a way for simultaneous chemical production in this study. Energy and exergy analyses were applied to each component of the system (e.g. pumps heat exchanger PV-T PEME and separation unit (SPU)) and the whole system to assess the system performance. The mathematical modelling of the whole system along with its main components except for the SPU was done using the Engineering Equation Solver (EES) software package while the SPU was modelled through the ASPEN Plus. A detailed modelling of the PEME was also included. The effects of the PV-T and PEME parameters on energy and exergy efficiencies of the system were evaluated while the improvement potentials and scale up options were discussed. Energy and exergy efficiencies of the proposed system at the optimum operation of the PEME and under average climatic conditions in the city of Izmir Turkey were determined to be 27.8% and 3.1% respectively. Energy and exergy efficiencies of the system were mainly regulated by the PV-T and PEME whose energy and exergy efficiencies were 40.6% 56.6% and 13.8% 14.1% respectively. Effective PEME parameters for energy and exergy efficiencies of the system were membrane conductivity membrane thickness anode catalyst and the operation temperature of the PEME. By changing the PV-T and PEME parameters and by scale-up energy and exergy efficiencies of the system could be improved. © 2021 Elsevier B.V. All rights reserved.
Citation - WoS: 33
Citation - Scopus: 32
Microwave assisted synthesis of La1 - xCaxMnO3 (x=0- 0.2 and 0.4): Structural and capacitance properties
(ELSEVIER SCI LTD, 2017) Taymaz Tabari; Dheerendra Singh; Atalay Calisan; Mehdi Ebadi; Haman Tavakkoli; Basar Caglar; Calisan, Atalay; Tavakkoli, Haman; Tabari, Taymaz; Ebadi, Mehdi; Caglar, Basar; Singh, Dheerendra
The effect of calcium incorporation on the physicochemical and electrochemical properties of the LaMnO3 (LM) perovskites was studied via several techniques. Moreover a new microwave assisted method was used to synthesize La(1-x)Ca()M(x)nO(3)(LCM) perovskites with various calcium content (x = 0.2 and 0.4). Then the physicochemical properties of the materials such as crystal structure particle size surface area reducibility and band gap energy were investigated by X-ray Diffraction (XRD) High resolution Scanning and Transmission Electron Microscope (HR-SEM and HR-TEM) BET analysis Temperature-programmed Reduction (TPR) and UV-visible Diffuse Reflectance Spectroscopy (UV-VIS DRS). The increase in partial concentration of calcium resulted in a high specific surface area larger particle size and an enhanced reducibility along with an increase in the band gap energy. In addition cyclic voltammetry was applied to LM and LCM perovskites to determine the effect of calcium incorporation on the capacitance of the electrochemical cell. It showed that the capacitance decreases with the amount of Ca2+ incorporated into the LM structure. This effect is linked to the formation of Mn4+ which hinders the electron transfer in the structure. The decline in the charge transfer is revealed by the specific capacitance. Finally our findings showed that the microwave assisted method provides a green efficient and time-saving route for perovskite synthesis and the calcium incorporation induces a negative effect on the capacitance properties of the LM perovskites.