Browsing by Author "Ünal, Fatih"

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An Applıcatıon Of Exergoeconomic Analysıs For Power Plants
(Vinča Institute of Nuclear Sciences, 2018) Ünal, Fatih
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.
CONDENSATION ANALYSIS OF THE INSULATION OF WALLS IN MARDIN PROVINCE ACCORDING TO DIFFERENT LOCATIONS
(2019) Ünal, Fatih
In this study, condensation and vapor diffusion caused by different positioned insulation in the wall were analyzed for Mardin province. In the analysis, according to the 2008 standard of TS 825, the MATLAB calculation program was used with the Glaser graphing method and graphical user interface (GUI). Extruded polyurethane foam was used as the insulation material and normal unreinforced concrete was chosen as the wall. Evaporation and condensation values were determined by creating 6 different wall models with the same insulation thickness of 20 cm and an unreinforced concrete wall was covered with 2 cm plaster on the inside with a 3 cm thickness on the outside. The data obtained for 2 cm and 4 cm insulation thicknesses are presented in tables and the results are interpreted for Mardin province. Consequently, it was seen that the worst wall structure in terms of condensation and evaporation was obtained in the middle insulated wall and later in the interior insulated wall structure. The externally insulated wall did not show any condensation.
Energy and exergy analysis of an industrial corn dryer operated by two different fuels
(International Journal of Exergy, 2021) Ünal, Fatih
In 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.
Energy, exergy and exergoeconomic analysis of solar assisted vertical ground source heat pump system for heating season
(Springer, 2018) Ünal, Fatih; Temir, Galip; Köten, 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.
Experimental analysis and modeling of the thermal conductivities for a novel building material providing environmental transformation
(Energy Sources, Part A: Recovery, Utilization and Environmental Effects, 2021) Ünal, Fatih; Koçyiğit, Fatih; Koçyiğit, Şermin
In this study, a mathematical equation was developed to determine the thermal conductivity of the materials by producing porous heterogeneous materials with expanded vermiculite aggregates, waste basalt powder, and the mixture of molten tragacanth added building materials. Experimental thermal conductivity of the samples was determined by using the hot wire method. Experimental thermal conductivity of the samples produced varied between 0.196 W/mK and 0.522 W/mK depending on the expanded vermiculite ratio, the ratio of waste basalt powder, and the ratios of tragacanth and cement. In addition, the developed mathematical thermal conductivity ranges from 0.201 W/mK to 0.455 W/mK. The experimental values deviated from the values in the developed model in the range of 3–19%. This equation was developed based on the porosity ratio of the produced samples, the density and thermal conductivity of the materials in the samples. The thermal conductivity results obtained by the experimental and theoretically developed equation were compared with each other and it was observed that the results were compatible.
Lpg Yakıtlı Endüstriyel Yatay Tip Mısır Kurutma Tesisinin Enerji ve Maliyet Analizi
(Dicle Üniversitesi Mühendislik Fakültesi Mühendislik Dergisi, 2020) Ünal, Fatih; Bulut, Hüsamettin; Kahraman, Ahmet
Bu çalışmada kurutma havasının ısıtılmasında LPG kullanılan yatay tip mısır kurutma tesisinin kurutma odasına farklı kurutma havası giriş sıcaklıkları ile elde edilen sonuçlara bağlı olarak enerji ve maliyet analizleri yapılmıştır. Kurutma sürecinde, sisteme sabit hava debisinde farklı sıcaklıklarda (85°C, 90°C ve 95°C) kurutma havası gönderilerek belirlenen düğüm noktalarında sıcaklık(°C), bağıl nem(%) ve hava hızı(m/s) ölçülmüştür. Sistemde belirlenen 6 adet düğüm noktasından elde edilen verilere bağlı olarak yapılan enerji ve maliyet analizinde kurutma havası giriş sıcaklığı, ısıtıcı giriş havasının sıcaklığı ve bağıl nem değişimlerinin yakıt sarfiyatı, enerji verimliliği ve birim kurutma maliyet üzerindeki etkileri değerlendirilmiştir. Sonuç olarak, kurutma giriş havası sıcaklığının artmasının enerji verimliliğini düşürdüğü, birim kurutma maliyetini ve yakıt sarfiyatını artırdığı tespit edilmiştir. Isıtıcı giriş havasının bağıl neminin artması ile yakıt sarfiyatının ve birim kurutma maliyetinin arttığı ve enerji verimliliğinin düştüğü tespit edilmiştir.
Thin-Layer Drying Modeling in the Hot Oil-Heated Stenter
(International Journal of Thermophysics, 2020) Ünal, Fatih; Akan, Ahmet Erhan
Although the drying processes have an important place in the textile industry in terms of drying or various textile finishing applications, they are considered as an expensive process in terms of energy and time consumed. Therefore, it is of great importance to simulate with mathematical models the drying behavior of a stenter (ram machine), one of the most preferred convection dryers in the textile industry. For this purpose, in this study, modeling was attempted of the drying behavior of 67 % Cotton + 33 % Polyester containing Thessaloniki knit fabrics, using experimental data obtained from drying processes performed in 9 different drying operations in a 10-chamber hot oil-heated stenter and 12 different empirical and semi-empirical thin-layer models that are frequently used in the literature. R2 values from regression analysis were evaluated as the primary factor in the model fit selection. According to the results obtained, it was understood that the Diffusion Approach model with R2 values ranging from 0.9991 to 0.9999, Two Term Model with R2 values ranging from 0.9995 to 0.9999, and the Modified Henderson and Pabis model with R2 values ranging from 0.9995 to 0.9999 gave the most appropriate results upon simulating drying behavior. In this regard, this study, which contains explanatory information on the drying behavior in a stenter, is thought to be useful to researchers.