Yazar "Karabuğa, Arif" seçeneğine göre listele

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    Advanced exergy analysis of cryogenic liquefaction system
    (Institute of Thermal Technology, 2019) Karabuğa, Arif; Utlu, Zafer; Selbaş, Reşat
    The elements in the air are separated by different methods and these elements are basically liquefied by three different methods (cryogenic, pressure swing adsorption and membrane). In this study, advanced exergy analysis of the nitrogen liquefaction unit was performed using the cryogenic liquefaction method. Advanced exergy analysis consists of four different splitting. These; endogenous/exogenous and avoidable/unavoidable exergy destruction. In the study, forward exergy analysis was performed for each component and endogenous, exogenous, unavoidable and avoidable values of these components were calculated. In the result of the study, the highest endogenous exergy degradation was found in the CM1 compressor with 32.56 kW, the highest exogenous exergy destruction was in the HE3 heat exchanger with 25.8 kW, the highest unavoidable exergy destruction was in the CM1 compressor with 22.55 kW and the highest avoidable value was in the HE1 heat exchanger with a value of 17.76 kW. Total exergy destruction of system were calculated as 755.08 kW.
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    Application of artificial neural network model for forecast energy efficiency of the cryogenic liquefaction system in the meaning of sustainability
    (Inderscience Enterprises Ltd, 2021) Altıntaş, Elif; Tolon, Mert; Karabuğa, Arif; Utlu, Zafer
    Sustainable engineering approaches are a necessity for improving efficiency. For this reason, the artificial neural network (ANN) model is used to forecast different types of energy efficiency problems. In this paper, a comparison is made between a simple model based on ANN which gives meaningful findings in terms of thermodynamics and a model that is based on thermodynamic principles as auditing and predicting tool to forecast exergy efficiency of the system by applying different ANN architecture types with 441 data of experimental measurements obtained from liquefied nitrogen and analysed the Engineering Equation Solver (EES) program to make an exergy analysis.
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    Energetic and exergetic analysis of thermophotovoltaic systems
    (Institute of Thermal Technology, 2019) Utlu, Zafer; Karabuğa, Arif
    Thermodynamic analysis of the thermophotovoltaic system was carried out in our research and the results are presented. Firstly, the thermophotovoltaic system was analyzed in three different regions. In the analysis, each part of the system is taken separately, while the whole system is handled separately. In the system, the first analysis was resolved following the first law of thermodynamics and the second according to the second law.The first region is the thermodynamic analysis of the heat source of energy that occurs with radiation until it reaches the filter. The second region is where the filter, selective-emitter and photovoltaic cells, considered as photovoltaic systems, take place. The heat radiating from the heat source is evaluated within the scope of the thermodynamic analysis of the heat generated by the electrospinning and the electromotive force of each element. The third region, which is expressed as the last region, is considered to be the part where electric energy is stored. Within the thermodynamic analysis of each region, energy and exergy analysis were carried out and the system was analyzed from part to part. As a result of this induction method, a general energy and exergy efficiency of the whole thermophotovoltaic system is determined. Our results are supported by formulas. It is aimed that the work done will be an alternative to the existing electricity generation and will form a resource for future Works.
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    Evaluation of electrical field effects of façade type a PV panel with occupational health and safety perspective, a case study
    (ECOS 2020 Local Organizing Committee, 2020) Erten, Begüm; Karabuğa, Arif; Utlu, Zafer
    In this study, the trend towards sustainable building concept has increased considerably in recent years. For this reason, the environmental impacts of photovoltaic (PV) systems integrated into the building have been examined in terms of occupational health and safety (OHS) for buildings that produce their own energy. In addition, the efficiency of the integrated PV systems outside the building is discussed. Therefore, the study is based on two main factors such as environmental effects and system efficiency. We measured the electrical field (electric, magnetic and electromagnetic) of the façade type PV system that building-integrated in Turkey for investigating the environmental effect. The measurements are carried out using the relevant standards, legal regulations and measurement methods at a total of 16 points in the front, top, back and in the inverter room of the panel one day per month for one year. The measurements include the electrical field values of the PV system area, the indoor areas covered by the PV area and the inverter room where the electrical systems are located. The measurements made in the inverter room are evaluated separately, since people are not intense and are located in a separate room. There are specific situations in terms of danger and risks due to the different functioning in this area. Measurement results are interpreted in accordance with OHS rules and legal regulations in terms of human, environment and workplace. While this study highlights the effects of electrical field effects occurring in façade type PV systems in terms of the OHS, it contributes to the proactive approach, which is the main purpose of the OHS. In result of this study, we have obtained during the measurement period, electric field values vary between 0.053 and 0.096 V/m. In addition, we have measure electromagnetic flux values are between 0.154 and 0.242 Gauss.
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    Examination of the liquefaction system for the use of different cryogenics in terms of thermodynamic analysis
    (Inderscience Enterprises Ltd, 2019) Karabuğa, Arif; Utlu, Zafer; Selbaş, Reşat
    Energy consumption in the world is increasing day by day. In addition to diversifying energy resources, it is also important to reduce energy consumption. In order to find the actual consumption of a thermodynamic system, energy efficiency as well as exergy efficiency should be done. The purpose of this study is to determine the parameters affecting the exergy efficiency of the cryogenic liquefaction unit integrated into a real cryogenic air separation unit. Cryogenic liquefaction is one of the basic processes between liquefaction methods. In addition to this process, absorption and membrane are used in methods. The main difference in the selection of these methods is the desired purity rates. Cryogenes are defined as fluids used in cryogenic cooling. In this study, five different cryogenes in the air are investigated. The energy and exergy analysis of the liquefaction unit for each cryogen is made. As a result of the study, the highest COPactual value is obtained with 0.3105 hydrogen fluid and the highest COPrev value with 0.8551 oxygen. Exergy of the system is found as 0.48 with hydrogen.
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    Investigation of performance of thermal power plants in terms of advanced exergy analysis approach
    (ECOS 2020 Local Organizing Committee, 2020) Karabuğa, Arif; Utlu, Zafer; Yıldız, Oğuzhan
    In this study, the conventional and advanced exergy analysis of a thermal power plant is carried out in Turkey. Energy and exergy balances are established for each component in the system and exergy destruction rates of the system and components are determined. The results obtained are assessment with a new concept, advanced exergy analysis, and the causes of exergy destruction are determined by a detailed examination of the exergy destruction. The system examined is a 1034 MW power generation system. In order to perform traditional and advanced exergy analysis on the system, thermophysical values are measured by determining twenty seven points at the inputs and outputs of each component. As a result, the total exergy destruction of the system is calculated to be approximately 382.3 MW. In addition, the highest exergy destruction among the components is found in the combustion chamber. Therefore, it is predicted that the component with the highest improvement potential is the combustion chamber.
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    Modelling of energy and exergy analysis of ORC integrated systems in terms of sustainability by applying artificial neural network
    (Oxford University Press, 2021) Utlu, Zafer; Tolon, Mert; Karabuğa, Arif
    The present study focuses on the organic Rankine cycle (ORC) integrated into an evacuated tube heat pipe (ETHP), whose systems are an alternative solar energy system to low-efficiency planary collectors. In this work, a detailed thermodynamic and artificial neural network (ANN) analysis was conducted to evaluate the solar energy system. One of the key parameters of sustainable approaches focused on exergy efficiency is application of thermal engineering. In addition to this, sustainable engineering approaches nowadays are a necessity for improving the efficiency of all of the engineering research areas. For this reason, the ANN model is used to forecast different types of energy efficiency problems in thermodynamic literature. The examined system consists of two main parts such as the ETHP system and the ORC system used for thermal energy production. With this system, it is aimed to evaluate energy and exergy analysis results by the ANN method in the case of integrating the ORC system to ETHP, which is one of the planar collectors suitable for the roofs of the buildings. Within the scope of this study, the exergy efficiency was evaluated on the developed ANN algorithm. The effect rates of parameters such as pressure, temperature and ambient temperature affecting the exergy efficiency of ORC integrated ETHP were calculated. Ambient temperature was found to be the most influential parameter on exergy efficiency. The exergy efficiency of the whole system has been calculated as similar to 23.39%. The most suitable BPNN architecture for this case study is recurrent networks with dampened feedback (Jordan-Elman nets). The success rate of the developed BPNN model is 95.4%.