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Öğe Alternative fuel production from waste plastics and their usability in light duty diesel engine: Combustion, energy, and environmental analysis(Elsevier Ltd, 2023) Mohan, Revu Krishn; Sarojini, Jajimoggala; Rajak, Upendra; Verma, Tikendra Nath; Ağbulut, ÜmitGreen biofuels have long been touted as a potential solution to society's reliance on fossil fuels and pollution emission problems. Commercially available renewable fuels like waste plastics oil alternative (P) made from waste plastic oil could take the place of fossil fuels, especially in diesel engines. Binary alternatives and diesel blends that partially replace diesel can be used in diesel engines without requiring major modifications. A four-stroke diesel engine used in the experiment was fed waste plastics oil alternative (up to 40% volumetric content), and diesel (D) mixes. Each binary blend is stabilised by a volumetric concentration and is composed of varying oil proportions. The investigations, therefore, relate partial diesel replacements to assessments of engine performance and mix combustion under various load conditions (25–100%), speeds (1200–1800 rpm), and compression ratios (15–19). Results showed that alternative-diesel mixtures up to 40% can still operate reliably. Thermal efficiency was somewhat lower than for diesel which was 100%. The experiment revealed higher fuel use, smoke, and NO emissions. The conclusion of the present research states that waste product oils can compete with fossil fuels in terms of engine performance, combustion, and emission characteristics when utilized in light-duty engines. © 2022 Elsevier LtdÖğe Collective influence and optimization of 1-hexanol, fuel injection timing, and EGR to control toxic emissions from a light-duty agricultural diesel engine fueled with diesel/waste cooking oil methyl ester blends(Institution of Chemical Engineers, 2023) De Poures, Melvin Victor; Dillikannan, Damodharan; Kaliyaperumal, Gopal; Thanikodi, Sathish; Ağbulut, Ümit; Hoang, Anh Tuan; Mahmoud, Z.This study attempts to utilize a ternary blend comprising diesel, biodiesel, and 1-hexanol in a direct injection (DI) diesel engine. A response surface methodology (RSM) based optimization with the full factorial experimental design was used to optimize the fuel injection timing and exhaust gas recirculation (EGR) with an objective to maximize the performance of the engine with minimum emissions. Three injection timings and three EGR rates were used. Multiple regression models developed using RSM for the responses were found to be statistically significant. Interactive effects between injection timing and EGR on responses for the blends were studied. From a desirability approach, a HX20 blend (diesel 50 v/v% + biodiesel 30 v/v% + 1-hexanol 20 v/v%) injected at lesser fuel injection timing and EGR rate delivered optimum emission and performance characteristics. Confirmatory tests validated the models to be adequate. With reference to diesel, at optimum conditions, there was a significant reduction in nitrogen oxides (NOx) emission with a marginal increase in smoke, hydrocarbon (HC) and carbon monoxide (CO) emissions. Also, it was found that there was minimal loss in brake thermal efficiency (BTE) of the engine. With respect to waste cooking oil methyl ester operation, the blend reduced nitrogen oxides (NOx), smoke, carbon monoxide (CO) and hydrocarbon (HC) emissions significantly with marginal loss in BTE. © 2023 The Institution of Chemical EngineersÖğe Combustion, performance, vibration and noise characteristics of cottonseed methyl ester-diesel blends fuelled engine(Taylor & Francis Ltd, 2019) Sarıdemir, Suat; Ağbulut, ÜmitAn experimental study was conducted to evaluate the impacts of using cottonseed methyl ester as an additive into neat diesel fuel on the combustion, performance, vibration and noise characteristics of a single-cylinder, direct injection diesel engine at a constant engine speed (1500 rpm) and under different engine loads (2.5, 5, 7.5 and 10 Nm). B-10, B-20 and B-50 fuel blends were prepared as the working fuels and compared to B-0 reference fuel (neat diesel fuel) in the study. The results indicated that the lowest average vibration value was also obtained in B-20 type fuel. It was observed that cottonseed methyl ester due to the high oxygen content improved the quality of combustion process. Additionally, the high viscosity value of the used biodiesel increased the ignition delay by adversely affecting the atomisation, evaporation and mixing ratio of the fuels. On the other hand, BSFC increased with the increment of the biodiesel ratio in the blends i.e. the maximum BSFC was observed in B50 fuel type. In all fuel blends except for B-50 type, IPmax values were achieved higher than B-0 for each engine load. In conclusion, the experimental results clearly reported that the presence of cottonseed methyl ester in the blends can alternatively be substituted for the neat diesel fuel without any modifications in diesel engines.Öğe A comprehensive review on the usage of the nano-sized particles along with diesel/biofuel blends and their impacts on engine behaviors(Elsevier Ltd, 2023) Gad, Mohammed Sayed; Ağbulut, Ümit; Afzal, Asif; Panchal, H.; Jayaraj, S.; Qasem, N.A.A.; El-Shafay, A. S.Global warming, climate change, air pollution, and harmful exhaust emissions for human health are highly associated with the burning of petroleum fuels at a huge level. In the beginning, biodiesel fuels have been introduced as a promising alternative fuel to mitigate these problems. However, poor atomization, low energy content, high viscosity, and density of biodiesels are the main obstacles to the frequent usage of biodiesel fuels in diesel engines. That is because biodiesel fuels in CI engines have generally resulted in higher fuel consumption, lower thermal efficiency, and higher NOx emission. On the other hand, most fuel researchers recently announced that the addition of nanoparticles in biodiesel blends has led to making biodiesels attractive again by significantly improving their poor biodiesel properties such as thermophysical properties, calorific value, heat transfer rate, evaporation rate, etc. From this point of view, many published papers in the area demonstrated that the addition of nanoparticles in biodiesel blended fuels has simultaneously provided fewer exhaust emissions, better performance, and combustion characteristics thanks to the high catalyst effect of nanoparticles. In the conclusion, the present review paper clearly announced that the addition of nanoparticles is a very strong way to re-improving the worsened engine combustion, performance, and emission characteristics of biodiesel-diesel blends. © 2023 Elsevier LtdÖğe Current practices, potentials, challenges, future opportunities, environmental and economic assumptions for Türkiye's clean and sustainable energy policy: A comprehensive assessment(Elsevier Ltd, 2023) Ağbulut, Ümit; Yıldız, Gökhan; Bakır, H.; Polat, Fikret; Biçen, Yunus; Ergün, Adem; Gürel, Ali EtemIn today's world, most countries including Türkiye have met their electricity demand at a dominant rate by burning fossil-based fuels in thermal power plants. However, fossil-fuel reserves have been rapidly depleted, resulting in high volatility in these fuels’ markets, as well as alarming environmental, and economic problems for the governments. In recent years, many governments have started to face these problems and have rapidly transitioned to renewable and alternative carbon-free energy sources in their electricity production variety. However, these belated steps have failed to mitigate the increment in global greenhouse gas emissions against the rapid growth of population and energy demand. In recent years, Türkiye has put a noteworthy challenge to mitigate its dominant use of fossil fuels, reducing its energy dependence, sustaining its economic development, and mitigating the carbon footprint. From this point of view, it is witnessed that many power plants have been established, many of them are currently under construction, especially to produce more electricity in a sustainable way. Accordingly, the present study aims to comprehensively discuss Türkiye's energy production policy, energy potential and reserves, challenges, future opportunities, and the impacts of the energy sector on the economic and environmental issues for the country. In this framework, it is well-noticed that the country's future energy production policy has been reasonably changed in order to achieve positive economic and environmental outcomes in the medium and long term. © 2023 Elsevier LtdÖğe Effect of the use of metal–oxide and boron-based nanoparticles on the performance in a photovoltaic thermal module (PV/T): Experimental study(Elsevier B.V., 2024) Dalmış, Muhyeddin; Gürel, Ali Etem; Yildiz, Gokhan; Ergün, Alper; Ağbulut, ÜmitRenewable energy sources are constantly on the agenda because the fossil fuels used are limited and the need for energy is constantly increasing. Among these resources, solar energy stands out because it is clean and endless energy. Nowadays, heat energy and electrical energy production from solar energy are quite common. Photovoltaic (PV) solar panels can convert a limited portion of the solar energy falling on them into electrical energy. In PV panels, heat energy that cannot be converted into electricity is discharged back to the external environment. Photovoltaic thermal (PV/T) panels are used to remove this heat from the system and convert it into useful energy. Many cooling techniques are applied to reduce the surface temperature of PV/T panels and increase their electrical efficiency. One of these techniques is liquid-cooled PV/T panels. In some of the studies, forced circulation (using a pump) and in others natural circulation (thermosiphon effect) were applied. In this study, a natural circulation indirect heated PV/T system was designed. Al2O3, ZnO, and BN nanoparticle concentrations were added to the cooling water to increase heat transfer within the PV/T panel. According to the experimental results, using nanofluid in the PV/T panel increased the thermal and total efficiency. Total efficiencies of ZnO, BN, and Al2O3 were obtained as 52.8 %, 47.86 %, and 43.49 %, respectively, at 0.03 concentration. The highest exergy efficiency and sustainability index were determined as 17.155 % and 1.207, respectively, at 0.03 concentration of ZnO nanofluid. © 2024 Elsevier B.V., All rights reserved.Öğe Energetic, exergetic, and thermoeconomic analyses of different nanoparticles-added lubricants in a heat pump water heater(Elsevier, 2022) Yıldız, Gökhan; Ağbulut, Ümit; Gürel, Ali Etem; Ergün, Alper; Afzal, Asif; Saleel, C. AhamedThe heat pumps are frequently used in domestic and industrial applications for hot water supply. The present paper aims to thermodynamically investigate the impacts of the nanoparticle-addition into the lubricants on the energetic, exergetic, and thermoeconomic aspects of a heat pump. In the experiments, air to the water heat pump is separately charged with various metal oxide-based nanoparticles (Al2O3, CuO, and TiO2)-added oils at a constant mass fraction of 0.5%. Polyolester (POE) and 134a are used as a lubricant, and refrigerant, respectively. The mass flow rates of the water passed through the condenser are varied from 10 to 25 g/s with an interval of 5 g/s. In the results, it is observed that the thermal conductivity value noteworthy increases with the presence of nanoparticles in POE. The highest increment in thermal conductivity is found to be 39% for POE + CuO in comparison with that of pure POE. Furthermore, with nanoparticles addition, it is noticed that the COP value generally improves, and the highest improvement for COP value is noticed to be 8% for POE + TiO2 nanolubricant at the mass flow of 25 g/s. Furthermore, exergy efficiency enhances by 3.6%, 1.8%, and 4.5% for POE + Al2O3, POE + CuO, and POE + TiO2, respectively. The lowest heating cost is calculated to be 3.465 c/kWh at 20 g/s flow rate for POE + Al2O3. In conclusion, this paper clearly reports that usage of nanoparticles along with lubricants is presenting better energetic, exergetic, and thermoeconomic results rather than the usage of lubricant alone in the heat pumps.Öğe Energy, exergy, environment and economic (4E) analysis of PV/T module assisted vapor compression refrigeration system: An experimental study(Elsevier Ltd, 2024) Yildiz, Gokhan; Gürel, Ali Etem; Katircioǧlu, Ferzan; Ağbulut, ÜmitDespite the rise in the prices of fossil fuels, the increase in their demand, and damaging the environment, a large part of the world's energy needs have been today met by fossil fuels. In this direction, interest in renewable energy sources has increased. Solar energy stands out among renewable energy sources because it is endless and clean. However, today, the use of solar energy is not used alone, but in combination with other thermal energy systems. In building applications, it is mostly used in heating, refrigeration, and HVAC systems, which have a high part in energy consumption. In this study, the solar energy and cooling system were not used separately as in previous studies but were used as a hybrid. The focus was on increasing the performance of both systems by operating them together. In this study, energy, exergy, thermoeconomic, and environmental analyses were applied to the PV/T-assisted vapor compression refrigeration system (PV/T-VCRS) at different storage temperatures (25 °C, 30 °C, and 35 °C). As a result, an 8.5 % lower surface temperature of the module in PV/T-VCRS 25 °C was measured compared to PV/T-VCRS 30 °C and 35 °C. In direct proportion to the module surface temperatures, 13 % better electrical efficiency was obtained in PV/T-VCRS 25 °C compared to 30 °C and 35 °C. The COP value increased by 15.46 % in PV/T-VCRS 25 °C compared to 30 °C and 35 °C. A 13 % improvement in exergy efficiency was observed in PV/T-VCRS 25 °C compared to 30 °C and 35 °C. The enviroeconomic parameter PV/T-VCRS is calculated as 15.17 ¢/h, 16.52 ¢/h, and 17.6 ¢/h for 25 °C, 30 °C and 35 °C. Another advantage of the system is that hot water is obtained at set temperatures. In PV/T-VCRS, 475 L, 300 L, and 210 L of hot water were obtained at 25 °C, 30 °C, and 35 °C, respectively. As a result, the performance of the PV/T-VCRS was good, with the added benefit of performing close to the performances when PV/T and VCRS were used separately. © 2024 Elsevier B.V., All rights reserved.Öğe Energy, exergy, environmental, and economic (4E) analyses of the usability of various nano-sized particles added lubricant in a heat pump system(Elsevier Ltd, 2024) Yildiz, Gokhan; Gürel, Ali Etem; Cingiz, Zafer; Ağbulut, ÜmitThe need for energy is rising significantly with the growth of technology in the world. This energy need is largely met by fossil fuels. The enhancement in their prices and the damage they induce to the environment, scientists have turned to alternative energy sources due to the depletion of fossil fuels. In recent years, these alternative energy sources have come to the fore as solar, wind, and wave energy. However, heating and refrigeration systems, whose share of energy consumption in buildings in the world is 40 %, can also compete with these alternative energy sources. In particular, heat pumps (HP) are at a level that can compete with renewable energy sources to seriously reduce this rate. In this study, different nanoparticles were added to the Polyol ester oil (POE) utilized in the compressor to enhance the performance of the HP. Thermodynamic, environmental, and economic performances of the obtained nanolubricants at different concentrations (0.5 wt% and 1 wt%) and flow rates (15, 30, and 45 g/s) were evaluated. The highest COP value of the HP was calculated as 4.14 at 0.5 wt% B-POE at 45 g/s. The best energy consumption in the HP was obtained with 0.5 wt% B-POE nanolubricant with a decrease of 10.96 % at 45 g/s compared to pure POE. The highest exergy efficiency in the HP was calculated at 0.5 wt% B-POE nanolubricant with a 13.53 % increase at 30 g/s compared to pure POE. The best exergoeconomic parameter (Rg,ex) performance was determined as 3.7148 kWh/$ in 1 wt% TiO2-POE nanolubricant at 45 g/s. The best enviro-economic value of 0.16182 ¢/h was obtained with 0.5 wt% B-POE nanolubricant at 45 g/s. In line with the results obtained, it was observed that the B-POE nanolubricant has a performance that can compete with the good-performing TiO2-POE nanolubricant. © 2024 Elsevier B.V., All rights reserved.Öğe Energy, exergy, sustainability and economic analysis of waste tire pyrolysis oil blends with different nanoparticle additives in spark ignition engine(Pergamon-Elsevier Science Ltd, 2022) Yaqoob, Haseeb; Teoh, Yew Heng; Sher, Farooq; Jamil, Muhammad Ahmad; Ali, Mubbashar; Ağbulut, Ümit; Salam, Hamza AhmadFossil fuels are the primary source of energy for most industries worldwide. However, its resources are finite and declining day by day, and toxic gases are released due to their consumption which causes global warming and problems with the health of the living. Therefore, any alternatives to fossil fuels or any additives added to the fuel needed to be found to minimize fuel consumption and the emission of harmful gases. In this study, a spark-ignition engine fuelled with blends of petrol with different concentrations of graphite nanoparticles, Fe2O3 nanoparticles, and tire pyrolysis oil (TPO) were used to conduct energy, exergy, economic, and sustainability analyses, and the obtained results were compared with neat petrol. The blends of petrol with 40 mg/L, 80 mg/L, and 120 mg/L of graphite nanoparticles & Fe2O3 nanoparticles, as well as 5% & 10% TPO, were used in a single-cylinder, four-stroke, air-cooled SI engine in this study. The experiments were conducted on various engine loads of 2 Nm to 10 Nm with an increment of 2 Nm at a constant speed of 3500 rpm. The maximum exergy and energy efficiencies were obtained 23.05% and 21.94% at a load of 8 Nm when the testengine fired with the P120FO blend, respectively. A maximum sustainability index of 1.3 for the P120FO blend was obtained. A minimum exhaust energy rate of 0.03241 kW was obtained for P120FO. A minimum exhaust exergy rate of 0.005849 kW was obtained for P90T10. Best results in energy efficiency, exergy efficiency, sustainability index, and economic analysis were obtained for the P120FO blend compared to neat petrol. Finally, it was concluded that the addition of nanoparticles in fossil fuel increases the engine's efficiency, decreases fuel consumption, and reduces the emission of harmful gases. (c) 2022 Elsevier Ltd. All rights reserved.Öğe An enhancement in diesel engine performance, combustion, and emission attributes fueled with Eichhornia crassipes oil and copper oxide nanoparticles at different injection pressures(Taylor & Francis Inc, 2022) Khan, Osama; Khan, Mohd Zaheen; Khan, Emran; Bhatt, Bhupendra Kumar; Afzal, Asif; Ağbulut, Ümit; Shaik, SaboorCurrent scenario of crude oil exhaustion and price rise has motivated researchers to opt and explore other forms of energy which are renewable and sustainable in nature. Waste plant oils have significant potential to become a viable alternative to petro-diesel fuel for transportation and manufacturing purposes. Esterification of unrefined waste oils has significantly addressed the issues mainly occurring due to highly viscous nature of the oil. This analysis aims to conduct a controlled study to examine the impact of injection pressure on the engine parameters amalgamated with copper (III) oxide composites as a nanofuel additive. Biofuel obtained from waste plants (Eichhornia Crassipes) is amalgamated with plain diesel in a 30:70 ratio and copper (III) oxide (Cu2O3) as nano-additive. It is essential to operate the engine over a wide range of injection pressures (180, 200, and 220 bar) for furnishing maximum efficiency when mixed with 90 ppm nano-additive volume fraction. The current analysis shows that the injection of nano-additives raises the injection pressure leads to enhanced engine combustion characteristics, including a maximum peak pressure and a faster heat release rate. At 220 bar, injection pressure with a 90-ppm volumetric fraction of nano-additives yielded superior results in comparison with its counterpart blends. The inclusion of nano-additives for increased injection pressures decreases emissions of hydrocarbon, oxides of nitrogen, and soot particles. Thus, biofuels engines benefit by enhanced injection pressure and decreased emission levels by successfully amalgamating copper (III) oxide as nano-additives. Combined effect of high pressure and nano-additive fuel furnishes a maximal progression of 3.5% in combustion efficacy and a 14% drop in BSEC with reduction of 14% in HC, 15% in NOx, and 15% in smoke.Öğe Environmental and economic assessment of a low energy consumption household refrigerator(Elsevier B.V., 2019) Gürel, Ali Etem; Ağbulut, Ümit; Ergün, Alper; Ceylan, İlhanEnergy consumption is the biggest obstacle in the economic growth of a country. In recent years, Turkey has imported around at the rate of three-quarters of its total energy demand. Upon the past 10-years running, Turkey paid nearly half a trillion dollars for its total energy bill. The big share of energy consumption has emerged from buildings. Therefore, energy savings have great importance, particularly in the buildings. A refrigerator is responsible for the most dominant electrical energy consumption rate with 32% in a house. Therefore, this paper proposes a novel household refrigerator design for reducing energy consumption. In the proposed design, the necessary air for the cooling process will be provided from outdoor ambient in appropriate weather condition. The compressor work will, thus, be decreased via this way, and contribute to a reduction in energy consumption. The results indicated that this system in 63 provinces can be effectively used between 1 and 4 months and help to reduce 36 million $ in Turkish electric energy bill with the use of only 1 year period. Additionally, a reduction of approximately 850,000 tons of CO2 annually in Turkey can be achieved by applying the proposed design in this study. Hereby, Turkey can contribute not only to be sustained economic growth but also to reduce harmful gas emissions arising from electricity generation methods in the country. © 2019 Karabuk UniversityÖğe Exergetic, exergoeconomic, and sustainability analyses of diesel-biodiesel fuel blends including synthesized graphene oxide nanoparticles(Elsevier Sci Ltd, 2022) Uysal, Cüneyt; Ağbulut, Ümit; Elibol, Erdem; Demirci, Tuna; Karagöz, Mustafa; Sarıdemir, SuatIn this study, graphene oxide nanoparticles were synthesized and added to 85 vol% diesel + 15 vol% biodiesel (D85B15) blend with amounts of 100 ppm, 500 ppm, and 1000 ppm to prepare D85B15GO100, D85B15GO500, and D85B15GO1000 blends, respectively. The prepared fuels were tested in a compression ignition diesel engine. The experiments were performed on various engine loads ranging from 3 Nm to 12 Nm with intervals of 3 Nm at fixed crankshaft speed of 2400 rpm. The results obtained from the experiments were used in the exergetic, exergoeconomic, and sustainability analyses of test engine. According to the results, D85B15GO100 had the highest exergy efficiency and sustainability index and the second-cheapest specific exergy cost of crankshaft work. As a result, at 12 Nm, the exergy efficiency, specific exergy cost of work produced by crankshaft, and sustainability index values of test engine were 25.82%, 75.82 $/GJ, 1.348 for D85B15, whereas these values were 27.05%, 77.52 $/GJ, 1.371 for D85B15GO100, respectively. Increase in graphene oxide nanoparticle content in the blend led to decrease in the exergy efficiency and sustainability index and increase in the specific exergy cost of crankshaft work. Finally, it can be concluded that D85B15GO100 is optimal fuel compared to the fuels tested in this study.Öğe Exergy, exergoeconomic, life cycle, and exergoenvironmental assessments for an engine fueled by diesel-ethanol blends with aluminum oxide and titanium dioxide additive nanoparticles(Elsevier Sci Ltd, 2022) Ağbulut, Ümit; Uysal, Cüneyt; Cavalcanti, Eduardo J. C.; Carvalho, Monica; Karagöz, Mustafa; Sarıdemir, SuatThis study develops energy, exergy, exergoeconomic, exergoenvironmental, and sustainability analyses for a compression ignition (CI) engine fueled with neat diesel (D100), 90 vol% neat diesel + 10 vol% ethanol (D90E10), D90E10 + 100 ppm Al(2)O(3 )nanoparticle (D90E10Al(2)O(3)), and D90E10 + 100 ppm TiO2 nanoparticle (D90E10TiO(2)). The experiments were performed on various engine loads (from 3 Nm to 12 Nm with 3 Nm increments) at a fixed crankshaft speed of 2400 rpm. D90E10Al(2)O(3) showed the best energy, exergy, exergoenvironmental, and sustainability results among all fuels. However, according to exergoeconomic analysis, the lowest cost of crankshaft work was obtained with D100, followed by D90E10Al(2)O(3). This means that D90E10Al(2)O(3) presented better exergoeconomic results than its base fuel D90E10 and D90E10TiO(2) but worse exergoeconomic results than D100. The addition of ethanol to D100 excessively increased the fuel cost. As a result, the crankshaft work cost flow rate is 0.7645 $/h for D100, 1.1123 $/h for D90E10, 1.1069 $/h for D90E10Al(2)O(3) and 1.1338 $/h for D90E10TiO(2). Similarly, the environmental impact rate of work is 250.8 mPt/h for D100, 264.2 mPt/h for D90E10, 245.6 mPt/h for D90E10Al(2)O(3 )and 248.7 mPt/h for D90E10TiO2. Increments in the engine load have led to increases in all environmental impact rates due to higher fuel consumption but caused a decrease in the environmental impact rate per exergy unit. In conclusion, it is well noticed that fuel blends with nanoparticles can be used as alternative fuels to their base fuels, but D100 (or an equivalent lower-cost fuel than D100) should be selected for cost-effectiveness purposes.Öğe Exergy, sustainability and performance analysis of ground source direct evaporative cooling system(Elsevier, 2022) Yıldız, Gökhan; Ergun, Alper; Gürel, Ali Etem; Ceylan, İlhan; Ağbulut, Ümit; Eser, Servet; Afzal, AsifA significant portion of global energy consumption is due to energy consumption in the buildings. Heating, cooling, and air conditioning systems have the largest share in this energy consumption. Evaporative cooling systems, which have the advantage of being economical, zero pollution, and easy maintenance are preferred to reduce energy consumption in buildings. These systems are used in many areas such as greenhouses, broiler houses, and warehouses. In this study, analyzes of exergy, sustainability, and cooling efficiency in four different situations of a ground source direct evaporative cooling system were made. The system was studied in four different cases. While the highest exergy efficiency was obtained in case 3 with 20.83%, the exergy efficiencies in other cases were obtained as 16.83%, 17.49%, and 18.36%, respectively. In addition, the highest specific exergy loss was determined as 100.51 J/kg in case 2, while it was calculated as 73.08 J/ kg, 80.23 J/kg, and 73.05 J/kg for the other cases, respectively. It is seen that the sustainability values are in parallel with the exergy efficiency when the evaporative cooling system is examined for four different cases. The sustainability values were determined as 1.20 for case 1, 1.21 for case 2, 1.26 for case 3, and 1.22 for case 4. It is determined that the exergy efficiency gives precise information about the usability and sustainability of the system when these situations are evaluated. The exergetic improvement potential (EIP) was determined as 0.061 for case 1, 0.082 for case 2, 0.063 for case 3, and 0.059 for case 4, respectively. Although the highest exergy efficiency is obtained in case 3, it has a higher recovery potential than case 1 and case 4. In addition, cooling efficiencies for four different cases were obtained as 33.70%, 34.81%, 41.69%, and 36.95%, respectively. The temperature differences between the room and ambient temperatures were determined as 1.45 degrees C, 1.21 degrees C, 1.6 degrees C, and 1.48 degrees C for each case, respectively.Öğe Experimental and CFD analysis of dimple tube parabolic trough solar water heater with various nanofluids(Springer Science and Business Media Deutschland GmbH, 2024) Arun, M.; Barik, Debabrata; Sharma, Prabhakar; Gürel, Ali Etem; Ağbulut, Ümit; Medhi, Bhaskar Jyoti; Bora, Bhaskor J.A solar collector is a device used to absorb energy from the sun by collecting solar radiation and turning it into electricity or heat. The material type and coating of a solar collector are utilized to enhance solar energy absorption. This research combines experimental and computational methods to examine the performance of a parabolic-type plate solar water heater (PTSWH). The nanoparticles-DI water at a rate of mass flow (MFR) of 0.5–3.0 kg/min in 0.5 kg/min increments were used in a tube-in-tube heat exchanger featuring dimpled inner tubes with a pressure-to-diameter (P/D) ratio of 3. The researchers examined the fluid flow patterns and heat transfer efficiency in a dimple texture tube using nanoparticles of TiO2, Al2O3, CuO, and SiO2 with a size range of 10–15 nm and a volume concentration (VC) of 0.1–0.5% in increments of 0.1%. Computational Fluid Dynamics (CFD) was used to explore and verify the impact of nanoparticle concentration on the PTSWH. It was revealed that CuO /DI-H2O at a nanoparticles VC of 0.3% and a MFR of 2.5 kg/min yielded the best PTSWH performance. With a nanoparticle concentration of 0.3% and MFR of 2.5 kg/min, the efficiency of PTSWH was increased by approximately 34.3% for TiO2, 32.3% for Al2O3, 38.4% for CuO, and 36.4% for SiO2. The results also show that the solar water heater’s thermal efficiency rose steadily with the rise in MFR. At a MFR of 2.5 kg/min, Cu/DI-H2O was found to have a higher Nusselt number than TiO2/DI-H2O, Al2O3/DI-H2O, and SiO2/DI-H2O, respectively, by 10.5%, 8.2%, and 5%. TiO2/DI-H2O, Al2O3/DI-H2O, Cu/DI-H2O, and SiO2/DI-H2O nanoparticle-coated dimple texturing tubes all had lower friction coefficients than a plain tube did. Finally, a comparison was made between the experimental and simulated data, and the overall variation of ± 3.1% was found to be within an acceptable range. © 2025 Elsevier B.V., All rights reserved.Öğe Experimental and numerical assessment of the rotary bed reactor for fuel-processing and evaluation of produced oil usability as fuel substitute(Elsevier, 2022) Gad, Mohammed Sayed; Ağbulut, Ümit; El-Shafay, A. S.; Panchal, Hitesh; Emara, Kareem; Al-Mdallal, Qasem M.; Afzal, AsifIn current work, waste tires recycling using pyrolysis was performed inside a rotary bed reactor without oxygen-producing oil, black carbon, and synthetic gas. In that respect, CFD analysis was applied using ANSYS software to design the reactor and test its material resistance to the temperature rise. Thermal and mechanical stresses were evaluated to find an acceptable reactor design. Pyrolysis of tires to oil was performed at a temperature of 420 degrees C. Tire and diesel oils blends of 5, 10, and 20% volume percentages were prepared for experimentation. Tire oil blends properties were close to crude diesel. Characteristics of combustion, performance and emissions of diesel engines that used tire oil blends were investigated compared to crude diesel. The thermal efficiency maximum decrease of TO20 was 21% in comparison to pure diesel. The maximum increases in CO, smoke, and HC emissions of TO20 were 35, 20, and 25% compared to diesel fuel, respectively. The highest decline in NOx emission of TO20 was 19% related to crude diesel fuel. Oil blends achieved the higher peak cylinder pressures about diesel fuel. In conclusion, lower volume percentages of up to 20% of tire and diesel oil blends are recommended to be used without any engine modifications.Öğe Experimental assessment of the influences of liquid-solid-gas fuel blends on DI-CI engine behaviors(Elsevier, 2022) Polat, Fikret; Yeşilyurt, Murat Kadir; Ağbulut, Ümit; Karagöz, Mustafa; Sarıdemir, SuatThis study aims to deeply investigate the effects of the boron nanoparticles reinforced diesel fuel along with various biogas (BG) flow rates (0.5, 1, and 2 L/min) on the engine performance and emission characteristics of a diesel engine. The tests were carried out using a single-cylinder, four-stroke, direct injection, compression-ignition engine at a constant engine speed of 1500 rpm and under the varying engine loads from 2.5 to 10 Nm with gaps of 2.5 Nm. In the results, it is seen that EGT started to decrease in both the addition of boron nanoparticles and the addition of biogas compared to that of conventional diesel fuel (DF). EGT reduced by 8.6% for DF+Boron test fuel, 14.4% for DF+Boron+ 0.5 BG, 21% for DF+Boron+ 1 BG, and 23.4% for DF+Boron+ 2 BG. Compared to diesel fuel, CO, NOx, and HC emissions decreased with the addition of nanoparticles at all loads. However, as the amount of biogas increased, CO and HC emissions increased, but NOx emissions decreased. CO emission dropped by 22.2% for DF+Boron test fuel, however, increased to be 5.6%, 16.7%, and 36.1% for DF+Boron+ 0.5 BG, DF+Boron+ 1 BG, and DF+Boron+ 2 BG respectively. NOx emission reduced by 4.9%, 8.6%, 10.7%, and 14.8% for DF+Boron, DF+Boron+ 0.5 BG, DF+Boron+ 1 BG, and DF +Boron+ 2 BG respectively. In comparison to that of conventional DF, the brake specific fuel consumption (BSFC) value decreased by 8.42% for DF+Boron test fuel due to high energy content of nanoparticles, but it increased by 10.94% for DF+Boron+ 0.5 BG, 28.01% for DF+Boron+ 1 BG, and 60.2% for DF+Boron+ 2 BG. In addition, brake thermal efficiency BTE value increased by 8.04% for boron-added test fuel, but it declined by 9.41% for DF+Boron+ 0.5 BG, 19.38% for DF+Boron+ 1 BG, and 32.2% for DF+Boron+ 2 BG as compared to that of DF. In the conclusion, it is noticed that the engine characteristics have worsened by the introduction of biogas into the cylinder, but these worsened characteristics can be improved with the presence of boron nitride nanoparticles. (c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.Öğe An experimental assessment on dual fuel engine behavior powered by waste tire-derived pyrolysis oil - biogas blends(Elsevier, 2022) Karagöz, Mustafa; Polat, Fikret; Sarıdemir, Suat; Yeşilyurt, Murat Kadir; Ağbulut, ÜmitThis paper is intended to investigate the usability of waste tire pyrolysis oil along with diesel and biogas dual fuel in the CI engines. In this framework, the waste tire chips are firstly pyrolyzed in the study, and then are volumetrically blended into the conventional diesel fuel (DF) at the ratio of 20%. The biogas flow rate changes as 0.5, 1, and 2 L/min when the engine is fuelled by P20 test fuel. Throughout the experiments, the engine runs at a fixed engine speed of 1500 rpm under 2.5, 5, 7.5 and 10 Nm. In the results, it is noticed that the unburnt emissions such as CO and HC considerably increases with the presence of pyrolysis oil and biogas in the cylinder due to the lack of oxygen and lower heating value of these fuels. However, the NOx firstly rises with the dieselpyrolysis oil blends by 2.21% but then pulls back with the introduction of biogas to the combustion chamber. It drops by 2.29%, 4.93%, and 11.14% for P20 + 0.5 BG, P20 + 1 BG, and P20 + 2 BG test fuels, respectively in comparison to that of DF. On the other hand, the engine performance worsens with the pyrolysis oil due to the lower energy content. Accordingly, the increment on BSFC is found to be 9.28%, 25.15%, 42.51%, and 67.68%, and the reduction on BTE is found to be 8.47%, 17.72%, 25.52%, and 33.48% for P20, P20 + 0.5 BG, P20 + 1 BG, and P20 + 2 BG test fuels, respectively. It is concluded that even if they worsen the engine performance and exhaust emissions, the burning of waste products in the forms of pyrolysis oil and biogas as fuel substitutions in CI engines seems a very promising way in terms of waste management, disposal the huge volume of waste products from the nature, and protection of rapidly depletion fossil fuel reserves.Öğe Experimental investigation of combustion, performance and emission characteristics of a diesel engine fuelled with diesel-biodiesel-alcohol blends(Springer Heidelberg, 2019) Ağbulut, Ümit; Sarıdemir, Suat; Albayrak, SerdarThe purpose of this study is to investigate the impacts of diesel-biodiesel-alcohol blends on the combustion, performance and emissions characteristics of a single-cylinder diesel engine. Tests were conducted at different engine speeds of 1750, 2250, 2750 and 3250 rpm and under full load. In this study, different fuels [called as reference diesel (D100), 20 vol% cottonseed methyl ester (D80C20), 10 vol% ethanol (D90E10) and finally the ternary type of their derivations (D70C20E10)], were used. The experimental results showed that the highest reduction values were observed on CO emission by 42%, 30% and 8% for the D90E10, D70C20E10 and D80C20 fuels, respectively. These reductions for HC emission were achieved as 40%, 31% and 23% for the D90E10, D70C20E10 and D80C20, respectively. On the other hand, the reductions of NOx and CO2 emissions were not sharp and varied between 2-7%. Besides the reductions on the exhaust emissions, biodiesel-ethanol blend presented better results in terms of HRRmax and CPmax than using biodiesel alone. Additionally, ignition delay of the biodiesel blends was longer than that of D100 fuel owing to their low cetane numbers. Combustion duration was shortened with the increment in engine speed because the turbulence increased in the combustion chamber at high engine speed. This case also improved the homogeneity of test fuels and increased the quality of the combustion process. As a consequence, this paper clearly reported that it is possible to achieve fewer emissions, the highest CPmax values with the presence of ethanol in biodiesel fuels rather than using biodiesel alone for diesel engines.
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