Browsing by Author "Erzen, Sevgi"

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Citation - WoS: 12
Citation - Scopus: 12
Comparative performance and thermoeconomic analyses of high temperature polymer electrolyte membrane based two hybrid systems
(PERGAMON-ELSEVIER SCIENCE LTD, 2021) Sevgi Erzen; Emin Acikkalp; Arif Hepbasli; Hepbasli, Arif; Erzen, Sevgi; Acikkalp, Emin
The main objective of this study is to compare the two systems in terms of the thermoe-conomic and the performance. The first one is called hybrid I and consists of high tem-perature polymer electrolyte membrane and thermocapacitive cycle. The second one is named hybrid II which is composed of high temperature polymer electrolyte membrane and thermoelectric generator. Thermocapacitive cycle and thermoelectric generator have various advantages such as generally lower cost and higher power density. So they have good potential to utilize waste heat. The performance parameters of the considered hybrid systems include power density energy efficiency exergy efficiency and exergy destruction rate. The results have shown that hybrid I is more advantageous than hybrid II. The maximum power density values for hybrid I and hybrid II are obtained to be 2536.91W and 2049.62W while their energy efficiencies are 77.4% and 76.8% respectively. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Citation - Scopus: 2
Design and Analysis of a Novel Solar Driven Multigeneration System for Providing Energy Requirement of A Building
(Institute of Electrical and Electronics Engineers Inc., 2019) Sevgi Erzen; Emin Açıkkalp; A. Hepbasli; Hepbasli, Arif; Erzen, Sevgi; Acikkalp, Emin
Primary energy sources fossil fuels mostly have been depleting and not only in industrial and commercial sectors but also in residential applications affect negatively the environment. One of the important solutions to these problems depends on renewable energy usage widely. One has focused on renewable energy-based multigeneration systems in the last decade. In this paper a solar driven multigeneration system is introduced and the simulation of this system is performed by using TRNSYS 18. The proposed system includes PV-T and PV panels a solid oxide fuel cell (SOFC) an electrolyzer a hydrogen compressor a hydrogen storage tank a generator a gas turbine cycle batteries an air-cooled chiller an absorption chiller hydrogen combustors a water storage tank a heat exchanger and control systems. In this system the producing heat cooling electricity and hydrogen are designed. This system is considered to be located in Izmir which is the third biggest in Turkey by population and the performance of the system is analyzed over a period of one year. © 2020 Elsevier B.V. All rights reserved.
Exergetic Performance Comparison between Steam-Heated and Closed-Cycle Heat Pump Applications for Lumber-Drying
(Institute of Electrical and Electronics Engineers Inc., 2019) Sevgi Erzen; Emin Açıkkalp; A. Hepbasli; Hepbasli, Arif; Erzen, Sevgi; Acikkalp, Emin
Exergy analysis is a very strong method to evaluate the performance of energy-related systems from the thermodynamic point of view. Because unlike the energy analysis exergy analysis enables to determine the location and amount of the irreversibilities which cause inefficiencies in the system and its components. In this study the results of exergetic performances of two various heating systems namely a steam-heated system and a closed-cycle heat pump system for lumber-drying are considered and compared for the first time to the best of the authors' knowledge. The thermodynamic inefficiencies of the system components are evaluated in parts. The results show that the condenser in the closed-cycle heat pump is the most important system component for efficiency improvement. By comparison various investigators reported in their similar studies that exergy efficiency values varied between 76-97%. © 2020 Elsevier B.V. All rights reserved.
Citation - Scopus: 3
Off-grid hybrid systems based on combined conventional and unconventional technologies: Design analyses and illustrative examples
(Elsevier, 2021) Sevgi Erzen; Emin Açıkkalp; A. Hepbasli; Hepbasli, Arif; Erzen, Sevgi; Açikkalp, Emin
In this section off-grid hybrid systems based on combined conventional and unconventional technologies are examined. Some non-conventional and relatively novel systems are considered. Some simple illustrative examples are provided to better evaluate the hybrid systems while their performance evaluations have been made. Considering the results obtained it can be concluded that these systems are quite promising on the basis of waste heat utilization and very promising for electricity generation from low-temperature heat sources. © 2022 Elsevier B.V. All rights reserved.
Citation - WoS: 21
Citation - Scopus: 26
Performance assessment of a biogas fuelled molten carbonate fuel cell-thermophotovoltaic cell-thermally regenerative electrochemical cycle-absorption refrigerator-alkaline electrolyzer for multigenerational applications
(PERGAMON-ELSEVIER SCIENCE LTD, 2019) Sevgi Erzen; Emin Acikkalp; Arif Hepbasli; Hepbasli, Arif; Erzen, Sevgi; Açıkkalp, Emin
In recent years there has been increasing interest in fuel cell hybrid systems. In this paper a novel multi-generation combined energy system is proposed. The system consists of a molten carbonate fuel cell (MCFC) a thermally regenerative electro-chemical cycle (TREC) a thermo photovoltaic cell (TPV) an alkaline electrolyzer (AE) and an absorption refrigerator (AR). It has four useful outputs namely electricity hydrogen cooling and heating. The overall system is thermodynamically modeled in a detailed manner while its simulation and modeling are done through the TRNSYS software tool. Power output cooling-heating and produced hydrogen rates are determined using energetic and exergetic analysis methods. Results are obtained numerically and plotted. The maximum power output from the system is 16.14 kW while maximum energy efficiency and exergy efficiency are 86.8% and 80.4%. The largest exergy destruction is due to the MCFC. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Citation - WoS: 15
Citation - Scopus: 18
Sustainability analysis of a solar driven hydrogen production system using exergy- extended exergy- and thermo-ecological methods: Proposing and comparing of new indices
(PERGAMON-ELSEVIER SCIENCE LTD, 2021) Sevgi Erzen; Canberk Unal; Emin Acikkalp; Arif Hepbasli; Erzen, Sevgi; Acikkalp, Emin; Hepbasli, Arif; Unal, Canberk
This paper aims at investigating and comparing some sustainability indices in the literature while proposing some new indices. A solar driven hybrid system made of a PV cell an alkaline electrolyzer and a PEM fuel cell is chosen to apply these indices because renewable-based stand-alone hybrid systems for generating electricity seem to be very promising for the future. Some sustainability indices and methods such as sustainability index exergetic sustainability index extended exergy accounting and thermo ecological cost analysis exist in the literature. In addition to these indices new indices proposed in this paper contain thermo-ecological cost (TEC) of irreversibilities extended TEC extended exergy-based sustainability index and the extended exergetic ecological index. A daily dynamic performance analysis is made for one year. According to the results exergy efficiency values range from 0.027 to 0.121 while extended exergy efficiencies vary between 0.08 and 0.14. Finally the proposed indices are classified for designing environmental cycles assessing environmental effects under operation conditions and evaluating sustainability in every aspect.