Makine ve Metal Teknolojileri Bölümü Koleksiyonu
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Article An Applıcatıon Of Exergoeconomic Analysıs For Power Plants(Vinča Institute of Nuclear Sciences, 2018) Ünal, FatihCurrently, 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.Article Citation - WoS: 4Citation - Scopus: 4Energy and exergy analysis of an industrial corn dryer operated by two different fuels(International Journal of Exergy, 2021) Ünal, Fatih; 17.05. Department of Machine and Metal Technologies / Makine ve Metal Teknolojileri Bölümü; 17. Vocational Higher School / Meslek Yüksekokulu; 01. Mardin Artuklu University / Mardin Artuklu ÜniversitesiIn this study, the data obtained after converting an industrial horizontal type corn dryer that meets its drying air temperature from coal to natural gas was compared by thermodynamic analyses. Before starting the drying process, it was assumed that the corn type DKC6050 with 24-25% corn inlet humidity dries when it reaches approximately 14% corn outlet humidity, which is the storage condition after the drying process. Energy and exergy efficiencies, drying rates, unit drying costs, specific moisture extraction rate, and specific energy consumption values of the analysed systems were determined using the data obtained from the experiments carried out at 90, 100 and 110 C drying temperatures. On the other hand, it was also determined that the unit drying cost was approximately 0.1-0.45 €/kg and the specific energy consumption was less than approximately 1,000-8,000 kJ/kgwater. Also, emission values released to the environment were calculated for both systems based on the amount of energy required for drying.Article Citation - WoS: 3Citation - Scopus: 3Energy Consumption of Defrosting Process in No-Frost Refrigerators(Yildiz Technical Univ, 2018) Ozkan, D. B.; Unal, F.Refrigerators have high energy consumption because they consume energy throughout the day, and they are used in all residences and in most offices. Designing more efficient models and, thus, decreasing the energy consumption of refrigerators have become necessary, owing to the global energy scarcity. The purpose of this study was to decrease energy consumption and increase the efficiency of the defrosting process in no-frost refrigerators. The defrosting process plays an important role in the energy consumption of no-frost refrigerators. The amount of energy needed for defrosting and the time it takes are important factors for manufacturers in terms of energy performance. Recently, a theoretical correlation was developed as a function of the frost thickness, heat flux, and frost density for estimating the defrosting time of an evaporator fin surface. The melting time of the frost on the fin was calculated by a mathematical model and compared to results that were obtained experimentally. The results were differed from the actual melting time as 4.7%.Article Citation - WoS: 5Citation - Scopus: 6THERMAL ANALYSIS OF DIFFERENT REFUSE DERIVED FUELS SAMPLES(DoiSerbia, 2021) Ayas, Gizem; Öztop, Hakan F.; 17.05. Department of Machine and Metal Technologies / Makine ve Metal Teknolojileri Bölümü; 17. Vocational Higher School / Meslek Yüksekokulu; 01. Mardin Artuklu University / Mardin Artuklu ÜniversitesiAs a result of the activities carried out by people to maintain their daily lives in different places such as homes, hospitals, hotels or workplaces, waste consisting of furniture, paint, batteries, food waste, sachets, bottles, fabrics, and fibers with the heterogeneous structure is called municipal solid waste. Secondary fuels with higher heating value, which are generated by recycling of non-recyclable and reusable wastes in municipal solid wastes, are called as refuse derived fuel (RDF). In this study, RDF1 (taken in December, winter season) and RDF2 (taken in June, summer season) samples obtained from different dates were used. The ultimate, proximate, calorific value, X-ray fluorescence, thermogravimetric analysis, and differential scanning calorimetry analysis were performed for these samples. Combustion characterization from RDF samples was investigated in the applied analyzes. The results of the content analysis made were examined separately and compared with the thermogravimetric analysis and differential thermal analysis combustion graph curves. It was revealed that the RDF1 sample had a better combustion compared to the RDF2 sample, as the ash amount and content obtained as a result of the combustion also supported other data. In addition, the results of the analysis show how different the RDF samples taken from the same region in two different months are different from each other.
