Browsing by Author "Acikkalp, Emin"

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Citation - WoS: 85
Citation - Scopus: 100
Advanced exergy analysis of an aircraft gas turbine engine: Splitting exergy destructions into parts
(Elsevier Ltd, 2015) Yasin Şöhret; Emin Açıkkalp; A. Hepbasli; Hikmet Tahir Karakoc; Acikkalp, Emin; Sohret, Yasin; Karakoc, T. Hikmet; Hepbasli, Arif
Advanced exergy analysis of an aircraft gas turbine engine is presented in this paper. In this framework the main exergy parameters of the engine components are introduced while the exergy destruction rates within the engine components are split into endogenous/exogenous and avoidable/unavoidable parts. Also the mutual interdependencies among the components of the engine and realistic improvement potentials depending on operating conditions are acquired through the analysis. As a result of the study the exergy efficiency values of the engine components are determined to be 89% 86% 60.6% and 98.6% of the low pressure compressor the high pressure compressor the combustion chamber and the gas turbine respectively. The system has low improvement potential because the unavoidable exergy destruction rate is 93.55%. The relationships between the components are weak since 81.83% of the exergy destruction is endogenous. Finally it may be concluded that the combustion chamber component of the engine should be focused on according to the results obtained. © 2017 Elsevier B.V. All rights reserved.
Citation - WoS: 75
Citation - Scopus: 80
Advanced exergy analysis of an electricity-generating facility using natural gas
(PERGAMON-ELSEVIER SCIENCE LTD, 2014) Emin Acikkalp; Haydar Aras; Arif Hepbasli; Aras, Haydar; Hepbasli, Arif; Acikkalp, Emin
This paper deals with the performance assessment of an electricity generation facility located in the Eskisehir Industry Estate Zone in Turkey using advanced exergy analysis method. The exergy efficiency of the system is determined to be 40.2% while the total exergy destruction rate of the system is calculated to be 78.242 MW. The exergy destruction rate within the facility's components is divided into four parts namely endogenous exogenous avoidable and unavoidable exergy destruction rates. Through this analysis the improvement potentials of both the components and the overall system along with the interactions between the components are deducted based on the actual operational data. The analysis indicates that the combustion chamber the high pressure steam turbine and the condenser have high improvement potentials. The relations between the components are weak because of the ratio of the endogenous exergy rates of 70%. The improvement potential of the system is 38%. It may be concluded that one should focus on the gas turbine and combustion chamber for improving the system being the most important components of the system. (C) 2014 Elsevier Ltd. All rights reserved.
Citation - WoS: 19
Citation - Scopus: 24
Advanced low exergy (ADLOWEX) modeling and analysis of a building from the primary energy transformation to the environment
(ELSEVIER SCIENCE SA, 2014) Emin Acikkalp; Cern Tahsin Yucer; Arif Hepbasli; T. Hikmet Karakoc; Acikkalp, Emin; Yucer, Cern Tahsin; Karakoc, T. Hikmet; Hepbasli, Arif
The main objective of the present study is to model analyze and assess a building heating system along with its main components through advanced low exergy method. This method is shortly called ADLOWEX and combines advanced exergy (AD) with low exergy (LOWEX) for the first time by the authors. In the ADLOWEX analysis method a building heating system is investigated from the energy production to the building envelope by dividing exergy destructions into four basic parts namely endogenous exogenous avoidable and unavoidable exergy destruction rates first. The mexogenous exergy destructions for all components are determined. The endogenous and exogenous exergy destructions of the system are 27% and 73% while the avoidable and unavoidable exergy destructions are 26.2% and 73.8% respectively. (C) 2014 Elsevier B.V. All rights reserved.
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.
Citation - WoS: 10
Citation - Scopus: 10
Dynamic thermo-ecological cost assessment and performance analyses of a multi generation system
(Elsevier Ltd, 2021) Canberk Ünal; Emin Açıkkalp; Mustafa Tolga Balta; A. Hepbasli; Acikkalp, Emin; Balta, Mustafa Tolga; Hepbasli, Arif; Unal, Canberk
The main objectives of this study are to perform a dynamic thermo-ecological cost (TEC) assessment and performance analyses of a multi generation system using the TRNSYS 18 software package for comparison purposes. The system has five outputs consisting of electricity clean water heating hydrogen and cooling. Multigeneration is made of an internal combustion engine fueled by natural gas a heat pump a reverse osmosis desalination plant and a magnesium-chlorine (Mg–Cl) thermochemical (TC) water splitting cycle. This cycle which appears to be a promising TC hydrogen production method is integrated to the multi generation system for producing hydrogen for waste heat recovery. Environmental effect of the system is also considered using the TEC method. In this contribution a new index namely the TEC of the irreversibility is presented and applied. Variation of emissions electricity exergy destruction and energy loss values for the considered system and Mg–Cl TC water splitting cycle as well as TECs of the electricity heat and the hydrogen are calculated through some parametric studies undertaken and presented in figures. It is determined that the multigeneration system has an energy efficiency value of 0.43 and a corresponding exergy efficiency of 0.38. As a result TECEL TECHEAT and TECH2values of the considered system are obtained to be 2.98 0.72 and 2.90 respectively. It may be concluded that the TEC is an effective method to assess the environmental performance of various energy systems and compare them with each other. © 2021 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 - WoS: 14
Citation - Scopus: 11
Extended exergy analysis of a novel integrated absorptional cooling system design without utilization of generator for economical and robust provision of higher cooling demands
(Elsevier Ltd, 2024) Aslı Tiktaş; Huseyin Gunerhan; A. Hepbasli; Emin Açıkkalp; Acikkalp, Emin; Tiktas, Asli; Hepbasli, Arif; Gunerhan, Huseyin
The focus of this study is on designing a novel system for the provision of high-capacity cooling and heating loads (4000 kW) with the utilization of absorption technology to increase economic viability and COP value of existing cooling plants via lower-grade waste heat sources (70 °C-90 °C). To achieve this aim in the novel system an integration including the LiBr-water solution based absorptional heat transformer (AHT) and absorptional cooling cycle (ACC) and flat plate solar collector (FPSC) systems was proposed. In the integration the utilization of the generator in the cooling cycle was avoided with the interaction of the high-temperature LiBr-water solution (120 °C-150 °C) from the AHT system and ACC system evaporator. In this way both the additional cost of the boiler and heat source and the enhancement of economic viability and COP value were achieved. Energy economic traditional and extended exergy sustainability and environmental analyses were implemented in this novel system. The COP value for the cooling system was determined to be 3.10 from energy analysis. This result forms a significant indicator for achieving of the main focus of the current study with the proposed novel system. The annual heating and cooling duty generations with this novel system were computed as 52.37 GWh and 52.40 GWh respectively. In the context of economically comparing the proposed system to other plants with similar scale that already exist the initial overall expenditure yearly operational expenses and the time it takes to recover the investment for the proposed system were set at $4.56 million $3.12 million and 1.75 years respectively. It is worth noting though that these figures fall within the range of $6–8 million $5–7 million and 5–10 years respectively for the currently operational plants. This result indicated that the proposed system provides a robust alternative to the existing cooling-heating cogeneration systems in terms of main output generation and is more economically viable. Also the novel system gained annually US$3.89 million in energy costs. The conventional exergy analysis results were summarized by forming an exergy flow and loss diagram namely the Grassmann diagram. In addition in this current study the novel extended exergy flow diagram indicating extended exergy content components energy carriers of the proposed system and exergy product rate streams was also proposed and drawn for the proposed system. © 2024 Elsevier B.V. All rights reserved.
Citation - WoS: 23
Citation - Scopus: 24
Novel combined extended-advanced exergy analysis methodology as a new tool to assess thermodynamic systems
(PERGAMON-ELSEVIER SCIENCE LTD, 2021) Emin Acikkalp; Hakan Caliskan; Onder Altuntas; Arif Hepbasli; Altuntas, Onder; Acikkalp, Emin; Hepbasli, Arif; Caliskan, Hakan
In this study a novel combined extended-advanced exergy analysis method is developed for assessing thermodynamic systems. The method is established by combining extended exergy analysis with advanced exergy analysis and the so-called extended-advanced exergy analysis. The methodology used in the novel analysis method is different from only extended exergy analysis and only advanced exergy analysis but the criteria are the same to reach the goal. This proposed method is applied to a gas turbine system as a case study to show its variability. The gas turbine system considered consists of a combustion chamber a compressor and turbine units. The conventional (Fuel-Product approach) advanced and extended exergy analyses are separately applied to the case study system for the comparison with the novel combined extended-advanced exergy analysis. It is seen that the combined extended-advanced exergy analysis results of the case study are not exactly the same with the advanced and extended exergy analyses? results. The reason for this is its comprehensive joint of various thermodynamic analysis methodologies integrating all materials capital labor energy and environmental effect instead of the relation between components and their improvement potentials in one analysis. But it is assessed that the novel analysis tool is able to apply all of those analyses into one simple methodology. The exergy efficiencies of the case study are 28% and 31% by considering the conventional and extended exergy analyses respectively. This means that all input parameters including labor capital and environment are used with better efficiency. Also the exogenous exergy destruction rate (159 kW) is higher for the combined extended-advanced exergy analysis (384 kW). This shows that the relations between other components are increased for the turbine. Another important change is shown in avoidable exogenous exergy destruction rate for the turbine increasing from 374 kW to 833 kW. This new combined method is useful to those who wish to apply advanced and extended exergy analyses through a new practical assessment way.
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.