Makine ve Metal Teknolojileri Bölümü Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12514/171

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Citation - WoS: 4
Citation - Scopus: 4
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.
Citation - WoS: 3
Citation - Scopus: 3
Energy 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%.
Citation - WoS: 37
Citation - Scopus: 44
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.
Citation - WoS: 4
Citation - Scopus: 3
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.
Citation - WoS: 78
Citation - Scopus: 92
Fuels properties, characterizations and engine and emission performance analyses of ternary waste cooking oil biodiesel-diesel-propanol blends
(SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS, 2019) Bencheikh, Kamel; Atabani, A. E; Shobana, Sutha; Mohammed, M. N.; Uguz, Gediz; Arpa, Orhan; Kumar, Gopalakrishnan; Ayanoglu, Abdulkadir; Bokhari, Awais
Application of biodiesel synthesized from waste-based raw materials with numerous solvents (higher chain alcohols) in diesel engines is a topic of great interest. This article examines the effect of biodiesel-diesel-propanol ternary blends. Physio-chemical properties, fatty acids composition (FAC), FT-IR, TGA, DSC, NMR along with some selected engine and emissions performance parameters were examined. Biodiesel was produced from waste cooking oil and exhibits excellent FAC that yields kinematic viscosity, cetane number, oxidation stability, higher heating value and iodine value of 3.93mm(2)/s, 58.88, 7.43 h, 39.45 MJ/kg and 64.92 g/100 g. Propanol blended biodiesel depicted an affirmative improvement in cold flow properties and decremented density. FT-IR and NMR results confirms the existence of biodiesel-diesel-propanol and prove their qualities as reliable methods. DSC and TGA results confirm that propanol reduces the onset and crystallization temperatures of the blends. Engine and emissions performance revealed that propanol addition further increased brake specific energy consumption (BSEC) and brake specific fuel consumption (BSFC) and reduced carbon monoxide (CO), exhaust gas temperature (EGT), nitrogen oxides (NOx) and smoke. This study proves the feasibility of the ternary blends with rewarding benefits in cold flow properties and densities besides acceptable engine and emissions performance results.
Citation - WoS: 27
Citation - Scopus: 27
Perspective of safflower (Carthamus tinctorius) as a potential biodiesel feedstock in Turkey: characterization, engine performance and emissions analyses of butanol–biodiesel–diesel blends
(Taylor and Francis Ltd., 2017) Al-Samaraae R.R.; Atabani A.E.; Uguz G.; Kumar G.; Arpa O.; Ayanoglu A.; Mohammed M.N.; Farouk H.
Safflower (Carthamus tinctorius) is widely farmed in Turkey. This study investigates the physicochemical properties of safflower biodiesel and its blends with Euro diesel and butanol. A polynomial curve-fitting method was used to predict kinematic viscosity and density of the ternary blends. Furthermore, characteristics such as DSC, FT-IR, UV-Vis and TGA were adopted to evaluate the influence of butanol addition on biodiesel–diesel blends. Engine performance parameters such as BP, torque and BSFC and emissions such as CO, HC, NOx and EGT were studied. Safflower methyl ester satisfied both EN 14214 and ASTM D 6751 standards regarding viscosity, flash point and density. However, iodine value was quite high. Oxidation stability fails to satisfy either standard. This is due to the high level of unsaturated fatty acids (91.05%). A reduction in BP, torque, HC and CO coupled with an increase in BSFC, NOx emissions and EGT was observed for all blends compared to Euro diesel. Overall, all blends appear to be good alternatives to biodiesel–diesel blends. This work supports that biodiesel can be blended with diesel and butanol as ternary blends (up to 20%) for use as a fuel in compression ignition (CI) engines. Therefore, combustion characteristics of blends shall be further investigated. © 2017 Informa UK Limited, trading as Taylor & Francis Group
Citation - WoS: 5
Citation - Scopus: 6
THERMAL ANALYSIS OF DIFFERENT REFUSE DERIVED FUELS SAMPLES
(DoiSerbia, 2021) Ayas, Gizem; Öztop, Hakan F.
As 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.
Citation - WoS: 3
Citation - Scopus: 6
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.

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