Browsing by Author "Unal, Fatih"

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APPLICATION OF EXERGOECONOMIC ANALYSIS FOR POWER PLANTS
(VINCA INST NUCLEAR SCI, 2018) Unal, Fatih; Ozkan, Derya Burcu
Currently, energy resources are rapidly consumed. Therefore, scientists and engineers study the effective use of energy. In the present study, a thermodynamic and exergoeconomic analysis was performed in a thermal power plant in Turkey. The study involved determining the thermodynamic properties of 27 node points in a thermal power plant unit, and this was followed by calculating energy and exergy values of every node. Mean exergy costs were calculated by establishing energy and exergy balances of the equipment with respect to the calculated results. Subsequently, lost and damaged energies and exergies were calculated, and exergoeconomic factors were determined. The equipments were compared with each other on a graph based on the obtained results. The maximum rate of exergy loss and cost of exergy destruction corresponded to 79.5% and 886,66 $/h, respectively. The maximum exergy losses in a thermal power plant occurred in the boiler, turbine groups, condenser, heating group, pumps, and auxiliary groups. The highest and second highest law efficiencies of the studied thermal power plant corresponded to 32.3% and 28.5%, respectively. The study also involved presenting suggestions for improvement. Additionally, exergoeconomic analyses were conducted while considering the power plants' investment and equipment maintenance costs. It is expected that the calculation method and the obtained results can be applied to other thermal power plants.
Energy, exergy and exergoeconomic analysis of solar-assisted vertical ground source heat pump system for heating season
(KOREAN SOC MECHANICAL ENGINEERS, 2018) Unal, Fatih; Temir, Galip; Koten, Hasan
The purpose of this study is to evaluate the experimental performance of a solar assisted vertical ground source heat pump system (VGSHP) for the winter climatic conditions of Mardin, which is in the South-Eastern Anatolia region of Turkey. For this aim, an experimental analysis was performed on solar assisted VGSHP system, which was designed to meet the heating needs of an experimental room, during the heating season (10.01.2013/03.31.2014). The experimentally obtained results were used to calculate energy, exergy and exergoeconomic analyses of the system and its components. The energy efficiency, exergy efficiency and exergoeconomic factors of the entire system were 67.36 %, 27.40 % and 60.51 %, respectively. In this study, the system was proposed for disseminating the use of alternative technologies supported by renewable energy systems and it has been tested for the first time in Mardin to meet its heating needs with convectional systems. The experimental results showed that the proposed solar assisted VGSHP system can be used for residential heating in Mardin and similar regions. As a result, it has been detected that the system is very effective in both reducing energy consumption and decreasing emissions of green-house gases.
Investigation of Energy Saving Potential in Buildings Using Novel Developed Lightweight Concrete
(Springer/plenum Publishers, 2020) Akan, Ahmet Erhan; Unal, Fatih; Kocyigit, Fatih
In this study, three different composite materials were produced from mixtures of natural and waste materials in different proportions. The produced composites were used to determine the insulation thickness of exterior walls of buildings located in 12 provinces selected from the four different climate zones of Turkey. The selection of provinces was made according to Turkish standard TS 825. The produced materials are thermal insulation elements that can be used instead of construction elements, such as brick, on the exterior walls of the buildings. In this study, only the heating of the buildings was considered and the number of heating degree days of the provinces was taken into account to determine the insulation thickness. The life cycle cost analysis method was used to determine the optimum insulation thickness. It was determined that the optimum insulation thickness values calculated for four different fuel types for the selected provinces varied between 0.170 m and 1.401 m. The annual energy requirement for the unit surface area of the exterior walls of the insulated buildings was determined to be 11,213-965,715 kJ center dot m(-2) per year. Moreover, it was determined that the insulation costs ranged between $ 22,841 m(-2) and $ 114,841 m(-2), and the payback period ranged from approximately 2.5 to 6.5 years. It was concluded that using these new types of materials in the determined regions were advantageous in terms of thermal insulation, fire resistance, mechanical properties, production costs, extra labor costs, and optimum insulation thickness.
Modelling of the Hourly Horizontal Solar Diffuse Radiation in Sanliurfa, Turkey
(Vinca inst Nuclear Sci, 2020) Beyazit, Nesrin Ilgin; Unal, Fatih; Bulut, Husamettin
Horizontal diffuse solar radiation has been calculated over various models by using the total radiation data obtained from the horizontal surface due to reasons such as lack of adequate measurements and expensive measuring instruments. hi this study, the measurements were calculated using the obtained data between the years 2009 and 2016 from solar radiation measurement system with solar tracking system, which belongs to the Department of Mechanical Engineering, Sanliurfa Harran University, Turkey. Three horizontal solar diffuse radiation models have been proposed by using the relationship between the diffuse radiation ratio and the clarity index obtained by eight years data. Horizontal solar diffuse radiation values were calculated and compared with the measurement data for Sanliurfa by using 15 models of diffuse radiation given in the literature and the results obtained from the models. The statistical errors of the proposed models and 15 different diffusive radiation models were calculated. As dijfuse radiation varies with time, it is determined that modelling of Model 1 and Model 2 obtained from Sanliurfa data gives better results in terms of clarity index constraints. Furthermore, although the desired success cannot be achieved with Model 2 in terms of t(stat), it has been determined that the relevant model provides better results than many models when compared to statistical errors. With the improvements to be made on Model 2, a local estimation model is thought to give better results.