Energy Systems Engineering / Enerji Sistemleri Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/4752

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  • Article
    Citation - WoS: 15
    Citation - Scopus: 16
    Proposal of Novel Exergy-Based Sustainability Indices and Case Study for a Biomass Gasification Combine Cycle Integrated With Liquid Metal Magnetohydrodynamics
    (Elsevier, 2023) Canpolat Tosun, Demet; Açıkkalp, Emin; Çağlar, Başar; Altuntaş, Önder; Hepbaşlı, Arif
    Exergy is considered a way to sustainability. Exergy-based analyses have been recently widely used for performance assessment and comparison purposes of energy systems from production to end-user while different sustainability related indices or indicators including exergetic concepts have been developed in the literature. In this regard, the present study proposed five different indices: (i) Exergetic Fuel Based Environmental Remediation Index (X), (ii) Exergetic Product Based Environmental Remediation Index (delta), (iii) Exergetic Fuel Based Total Environmental Remediation Index (beta), (iv) Exergetic Product Based Total Environmental Remediation Index (alpha), and (v) Improved Sustainability Index (ISI). These indices were applied to a novel Biomass-integrated Gasification Combine Cycle (BIGCC) integrated with Liquid Metal Magnetohydrodynamics (LMMHD). They allowed to perform a more complete environmental analysis by considering the exergetic cost of environmental remediation of the process. The average exergy efficiency values for the BIGCC, LMMHD and the overall system were determined as 0.491, 0.222 and 0.688 under daily ambient temperatures for a year and different air to fuel ratio (AFR) conditions, respectively. The average values for.X, beta, delta, alpha and ISI were 1.636, 2.389, 1.949, 2.848 and 0.513, respectively.
  • Article
    Citation - WoS: 31
    Citation - Scopus: 33
    Energy and Exergy Analysis of a Pv-T Integrated Ethanol Pem Electrolyzer
    (Pergamon-Elsevier Science Ltd, 2021) Çağlar, Başar; Araz, Mustafa; Özcan, Hüseyin Günhan; Çalışan, Atalay; Hepbaşlı, Arif
    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.
  • Article
    Citation - WoS: 22
    Citation - Scopus: 22
    Multiparameter-Based Product, Energy and Exergy Optimizations for Biomass Gasification
    (Elsevier, 2021) Çağlar, Başar; Tavşancı, Duygu; Bıyık, Emrah
    The thermodynamic modelling of biomass gasification was studied by using Gibbs free energy minimization approach. Different from the studies using the same approach, the simultaneous presence of all gasifying agents (air, H2O and CO2) was considered and a multiparameter optimization was applied to determine the synergetic effect of gasifying agents for hydrogen, syngas with a specific H2/CO ratio and methane production. The performance of gasification was assessed by using technical and environmental performance indicators such as product yields, cold gas efficiency, exergy efficiency, CO2 emission and the heat requirement of the gasifier. The results show that the simultaneous presence of gasifying agents does not create considerable changes in syngas yield, H2 yield, methane yield, CGE and exergy efficiency while it allows to tune the H2/CO ratio and the heat requirement of the gasifier. The highest syngas yield is observed at T > 1100 K and 1 bar and when SBR > 0.5 and/or CBR > 0.8 with the absence of air, at which CGE changes between 114% and 122% while exergy efficiency is between 77% and 86%. The results prove that CO2 offers several advantages as a gasifying agent and suggests that CO2 recycling from gasifier outlet is a useful option for the biomass gasification.