Yazar "Agbulut, Umit" seçeneğine göre listele
Listeleniyor 1 - 20 / 24
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Current practices, potentials, challenges, future opportunities, environmental and economic assumptions for Turkiye's clean and sustainable energy policy: A comprehensive assessment(Elsevier, 2023) Agbulut, Umit; Yildiz, Gokhan; Bakir, Huseyin; Polat, Fikret; Bicen, Yunus; Ergun, Alper; Gurel, Ali EtemIn today's world, most countries including Turkiye 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, Turkiye 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 sus-tainable way. Accordingly, the present study aims to comprehensively discuss Turkiye'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 envi-ronmental outcomes in the medium and long term.Öğe A detailed analysis of CPV/T solar air heater system with thermal energy storage: A novel winter season application(Elsevier, 2021) Ceylan, Ilhan; Gurel, Ali Etem; Ergun, Alper; Ali, Ismail Hamad Guma; Agbulut, Umit; Yildiz, GokhanThe interest in solar energy is increasing day by day because it is clean and limitless. Concentrated photovoltaic and thermal systems (CPV/T) are one of the systems that use in the winter and the summer, attract great attention among solar energy systems. The main purpose of this research is to discuss the capacity of a CPV/T to simultaneously convert solar energy into electrical energy and thermal energy, especially in winter seasons. While only thermal energy is obtained in many concentrated air collectors (CAC) used in the literature, in this study, energy is stored with the help of phase change material (PCM). Ethyl alcohol and water blend were utilized as a working fluid and paraffin wax was also utilized as a PCM. In this study, system performance was handled by applying energy, exergy and environmental economic analyzes. In the results, the average solar radiation was concentrated from 536 W/m(2) to 737 W/m(2). The average overall thermal efficiency and PV module efficiency of the CPV/T were calculated as 73% and 15%, respectively. In other words, the overall system efficiency of the CPV/T was obtained as 88%. The average exergy efficiency of the CPV/T was calculated as 10%. Concerning the environmental aspect, 1.11 kg of CO2 emission per hour into the atmosphere could be prevented by using such a system. In the conclusions, the present paper has reported that the integration of a PCM and air collector into a CPV/T system provided higher energy efficiency in the winter season.Öğe A detailed investigation of the temperature-controlled fluidized bed solar dryer: A numerical, experimental, and modeling study(Elsevier, 2022) Gurel, Ali Etem; Agbulut, Umit; Ergun, Alper; Ceylan, Ilhan; Sozen, Adnan; Tuncer, Azim Dogus; Khanlari, AtaollahSolar thermal systems are generally utilized for providing sustainable and environmentally friendly thermal energy that can be used in different applications. In the present study, a temperature-controlled fluidized bed solar drying system along with flat plate and plate with zigzag fins has been designed, manufactured, and experimentally tested. In the first step, the thermal behavior of designed solar air collectors has been numerically modeled. In the next step, the drying system's performance has been experimentally investigated. The overall efficiency of the system was found to be 64%. The maximum exergy efficiency of flat and zigzag plate solar air collectors was calculated as 7.2% and 11.6%, respectively. Then moisture content (MC) and moisture ratio (MR) values were modelled by response surface methodology (RSM), and the predicted results were compared with four metrics. It was found that the drying parameters were highly fitted with the mathematical models. MC metric was predicted with accurate values for performance criteria of R-2, R-RMSE, and MBE as 0.9995, 1.94%, and -0.0096, respectively. The general outcomes of numerical, experimental and modeling analyses of this research exhibited successfulness of the developed the fluidized bed solar drying system.Öğe Energetic, exergetic, and thermoeconomic analyses of different nanoparticles-added lubricants in a heat pump water heater(Elsevier, 2022) Yildiz, Gokhan; Agbulut, Umit; Gurel, Ali Etem; Ergun, 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, AND ENVIRONMENTAL (3E) ASSESSMENTS OF VARIOUS REFRIGERANTS IN THE REFRIGERATION SYSTEMS WITH INTERNAL HEAT EXCHANGER(Begell House Inc, 2020) Gurel, Ali Etem; Agbulut, Umit; Ergun, Alper; Yildiz, GokhanA comprehensive thermodynamic analysis of a refrigeration system with an internal heat exchanger was reported for four various refrigerants as an alternative to R134a. The preferred refrigerants in this paper have zero ozone-depleting potential and fairly low global warming potential value compared with reference R134a. These refrigerants are from both the HC group (R290 and R600a) and the HFO group (R1234yf and R1234ze(E)). Basically, the refrigeration system consists of a compressor, condenser, evaporator, expansion valve, and internal heat exchanger as well. Energy-exergy analyses and environmental impact assessments depending on the compressor energy consumptions are evaluated in the current study. The system performance was theoretically carried out at two different evaporation temperatures of 0 and -8 degrees C. Based on the obtained results from this study, the highest performance was achieved in R600a from HC group refrigerants and R1234ze(E) from HFO group refrigerants. As compared with R134a, in the COP value of R600a an increase of 3.2% at the evaporation temperature of 0 degrees C and 3.4% for the evaporation temperature of -8 degrees C was achieved. On the other hand, the COP value for R1234yf was decreased by 2% at the evaporation temperature of 0 degrees C and by 2.57% at the evaporation temperature of -8 degrees C. Considering the CO2 emissions, R600a was located at the first order in terms of the lowest CO2 emissions and R1234ze(E) follows R600a. In conclusion, R600a presented the highest performance compared with R134a in a refrigeration system with an internal heat exchanger.Öğe Energy, exergy, economic and sustainability assessments of a compression ignition diesel engine fueled with tire pyrolytic oil - diesel blends(Elsevier Sci Ltd, 2020) Karagoz, Mustafa; Uysal, Cuneyt; Agbulut, Umit; Saridemir, SuatEvery year, millions of tons of tire become unusable around the world and waste tire dumps threaten human health and the environment. Therefore, recycling of waste tires has attracted attention recently. In this study, energy, exergy, economic and sustainability analyses of a compression ignition diesel engine fueled with tire pyrolytic oil-diesel blends were performed and the results were compared with that of neat diesel. Tire pyrolytic oil was produced from waste tires with vacuum pyrolysis technique. Hydro-sulfuric acid treatment, vacuum distillation and oxidative desulfurization processes were applied to reduce emission values of tire pyrolytic oil. Tire pyrolytic oil was blended with neat diesel as 10 vol% (TPO10D90), 30 vol% (TPO30D70) and 50 vol% (TPO50D50). The test engine was single-cylinder, four-stroke, naturally aspirated, compression ignition diesel engine and the experiments were conducted for different test engine loads of 3 Nm, 6 Nm, 9 Nm and 12 Nm at constant crankshaft speed of 2000 rpm. The highest energy and exergy efficiencies were obtained for TPO10D90, while the lowest ones were obtained for neat diesel. At 12 Nm, the energy efficiency of test engine was obtained to be 26.89% for neat diesel and 28.15% for TPO10D90, while the exergy efficiency of test engine was found to be 25.19% for neat diesel and 26.36% for TPO10D90. The energy loss per capital investment cost was obtained to be 0.87 x 10(-4) kW/$ for TPO10D90 and 1.03 x 10(-4) kW/$ for neat diesel at 3Nm. At 12 Nm, the highest sustainability index was determined to be 1.358 for TPO10D90, while the lowest sustainability index was 1.337 for neat diesel. Results showed that TPO10D90 had better performance at each test engine load in terms of energy, exergy, economic and sustainability and the increase in tire pyrolytic oil content of blend made the results worse but better than neat diesel. As a conclusion, it can be said that tire pyrolytic oil production from waste tires is important fact from the viewpoint of both waste management and protection of fossil fuel resources depletion. (C) 2020 Elsevier Ltd. All rights reserved.Öğe Environmental and economic assessment of a low energy consumption household refrigerator(Elsevier - Division Reed Elsevier India Pvt Ltd, 2020) Gurel, Ali Etem; Agbulut, Umit; Ergun, Alper; Ceylan, IlhanEnergy 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. (C) 2019 Karabuk University. Publishing services by Elsevier B.V.Öğe Exergetic and exergoeconomic analyses of a CI engine fueled with diesel-biodiesel blends containing various metal-oxide nanoparticles(Pergamon-Elsevier Science Ltd, 2021) Karagoz, Mustafa; Uysal, Cuneyt; Agbulut, Umit; Saridemir, SuatComprehensive exergetic and exergoeconomic analyses of a single-cylinder, four-stroke, naturally aspirated compression ignition (CI) diesel engine were conducted in the present paper. Exergy-based sustainability indicators were also determined in the study. The test engine was fueled with diesel fuel (D100), %90 diesel+10% waste cooking oil methyl ester blend (D90B10), D90B10 with Al2O3 nanoparticle of 100 ppm (D90B10Al(2)O(3)), D90B10 with TiO2 nanoparticle of 100 ppm (D90B10TiO(2)), and D90B10 with SiO2 nanoparticle of 100 ppm (D90B10SiO(2)) nanofuels, separately. The tests were performed at a constant engine speed of 2000 rpm and at varying engine loads from 2.5 to 10 Nm with an increment of 2.5 Nm. As a result, the exergy efficiencies of the test engine for D90B10 and D90B10Al(2)O(3) were determined to be 25.57% and 28.12%, respectively. The lowest cost flow rate of crankshaft work was found to be 0.4247 US$/h at 2.5 Nm, 0.5154 US$/h at 5 Nm for D90B10Al(2)O(3), and 0.6029 US$/h at 7.5 Nm, 0.7253 US$/h at 10 Nm for D90B10SiO(2). At 10 Nm, the highest and lowest sustainability index values were determined to be 1.391 for D90B10Al(2)O(3) and 1.344 for D90B10, respectively. From the perspective of exergy and sustainability, D90B10Al(2)O(3) had the best results. Besides, from the perspective of exergoeconomics, D90B10Al(2)O(3) had the best results at lower engine loads. As a conclusion, it can be said that nanofuels showed better performances compared to neat diesel fuel and diesel-biodiesel blend in the terms of in terms of exergy, exergoeconomics, and sustainability analyzes. Considering all analyses together, it is noticed that Al2O3-doped nanofuel is the best test fuel for this study, and then it is followed by SiO2 and TiO2-doped nanofuels, respectively. (C) 2020 Elsevier Ltd. All rights reserved.Öğe Exergetic and exergoeconomic assessments of a diesel engine operating on dual-fuel mode with biogas and diesel fuel containing boron nitride nanoparticles(Springer, 2024) Uysal, Cuneyt; Agbulut, Umit; Topal, Halil Ibrahim; Karagoz, Mustafa; Polat, Fikret; Saridemir, SuatThis study investigates the exergetic and exergoeconomic analyses of a diesel engine operated on dual-fuel mode with fuelled both diesel fuel-boron nitride nanofuel and biogas purchased commercially. The experiments were performed for diesel fuel, diesel + 100 ppm boron nitride nanoparticle, diesel + 100 ppm boron nitride nanoparticle + 0.5 L min-1 biogas, diesel + 100 ppm boron nitride nanoparticle + 1.0 L min-1 biogas and diesel + 100 ppm boron nitride nanoparticle + 2.0 L min-1 biogas at various engine loads (2.5 Nm, 5.0 Nm, 7.5 Nm, and 10.0 Nm) and fixed crankshaft speed of 1500 rpm. The obtained experimental data were used to realize exergetic and exergoeconomic analyses. Among the fuels considered in this study, diesel + 100 ppm boron nitride nanoparticle nanofuel had the best exergetic and exergoeconomic results. As a result, at engine load of 10 Nm, the exergy efficiency of test engine and specific exergy cost of crankshaft work were obtained to be 29.12% and 124.86 US$ GJ-1 for diesel + 100 ppm boron nitride nanoparticle nanofuel, respectively. These values were 27.35% and 125.19 US$ GJ-1 for diesel fuel, 25.50% and 141.92 US$ GJ-1 for diesel + 100 ppm boron nitride nanoparticle + 0.5 L min-1 biogas, 23.10% and 156.33 US$ GJ-1 for diesel + 100 ppm boron nitride nanoparticle + 1.0 L min-1 biogas, and 21.09% and 171.92 US$ GJ-1 for diesel + 100 ppm boron nitride nanoparticle + 2.0 L min-1 biogas, respectively. It is clear that biogas addition to combustion made worse the exergetic and exergoeconomic performances of test engine. As a conclusion, it can be said that diesel + 100 ppm boron nitride nanoparticle nanofuel can be used as alternative fuel to D100 in terms of exergy and exergoeconomics.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) Agbulut, Umit; Uysal, Cuneyt; Cavalcanti, Eduardo J. C.; Carvalho, Monica; Karagoz, Mustafa; Saridemir, 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) Yildiz, Gokhan; Ergun, Alper; Gurel, Ali Etem; Ceylan, Ilhan; Agbulut, Umit; 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 analysis of CPV/T solar dryer with nano-enhanced PCM and prediction of drying parameters using ANN and SVM algorithms(Pergamon-Elsevier Science Ltd, 2021) Karaagac, Mehmet Onur; Ergun, Alper; Agbulut, Umit; Gurel, Ali Etem; Ceylan, IlhanIn this paper, a concentrated photovoltaic-thermal solar dryer (CPV/TSD) using nano-enhanced PCM (Al2O3Paraffin wax) is experimentally studied. A comprehensive thermodynamic analysis of the system according to the first and second laws is discussed. Besides, the drying parameters (moisture content and moisture ratio) are predicted using the two machine learning algorithms (ANN and SVM) and compared the prediction success with four evaluation metrics (R2, rRMSE, MBE, and rMAE). The overall thermal energy efficiency and exergy efficiency of the CPV/TSD system are found to be 20% and 8%, respectively. Although solar radiation to the environment has decreased a lot, it has been found that the thermal energy transferred to the nano-enhanced PCM prevents the decrease in greenhouse temperature for the first 100 min. In the system, mushrooms are dried from the initial moisture content of 17.45 g water/g dry matter to the final moisture content of 0.0515 g water/g dry matter. Then the drying rate value for CPV/TSD system is calculated to be 0.436 g matter/g dry matter.min. On the other hand, even if both ANN and SVM algorithms have exhibited very satisfying results, ANN is coming to the fore in the prediction of the drying parameters considering all evaluation metrics together.Öğe An experimental assessment of combustion and performance characteristics of a spark ignition engine fueled with co-fermentation biogas and gasoline dual fuel(Sage Publications Ltd, 2022) Agbulut, Umit; Aydin, Mustafa; Karagoz, Mustafa; Deniz, Emrah; Ciftci, BurakNatural gas, biogas and alcohols are alternative fuels for spark ignition engines which can be used for reducing exhaust emissions and improving performance metrics. At the first stage of the study, a pilot scale biogas system was built, and biogas was produced from a mixture of manure and water called slurry, consisting of 40% cattle manure, 35% water, 17% whey and 8% poultry manure by co-fermentation method. Scrubbing and desulfurization were applied to remove the harmful gasses (CO2, H2S) from the produced biogas in two stages. In the end of the purification process, biogas with a CH4 content of 51%, 57% and 87% was produced. In the second stage, these biogas fuels were used in an SI engine, and their impacts on performance and combustion characteristics were investigated experimentally. A 4-cylinder, 4-stroke, water cooled SI engine with an 11:1 compression ratio was used in the experiments. Tests were conducted at various loads and constant speed. Results showed that daily amount of mean biogas production has reached 1.6 m(3)/day and biogas methane content has reached 72%. In engine tests, as the methane ratio in biogas increases, cylinder pressure and exhaust temperature values increase and brake specific fuel consumption decreases.Öğe Experimental assessment of the influences of liquid-solid-gas fuel blends on DI-CI engine behaviors(Elsevier, 2022) Polat, Fikret; Yesilyurt, Murat Kadir; Agbulut, Umit; Karagoz, Mustafa; Saridemir, 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) Karagoz, Mustafa; Polat, Fikret; Saridemir, Suat; Yesilyurt, Murat Kadir; Agbulut, UmitThis 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 fusel oil (isoamyl alcohol) and diesel blends in a CI engine(Elsevier Sci Ltd, 2020) Agbulut, Umit; Saridemir, Suat; Karagoz, MustafaThe present paper details an experimental investigation of the combustion behaviours, exhaust emission and performance characteristics of a single-cylinder diesel engine fueled with fusel oil-diesel blends of volumetrically 10%, 15% and 20% into neat diesel fuel (F0) separately. Under steady-state conditions, the tests were performed at constant engine speed (2000 rpm), and four different engine loads (2.5, 5, 7.5 and 10 Nm). The results showed that CO and NOx emissions significantly reduced down to 52% and 20%, respectively with an increasing percentage of the fusel oil in the fusel oil-diesel blends. However, HC gradually increased up to 40% with the addition of fusel oil. With respect to the performance of the engine, the lowest BSFC and the highest BTE were seen in F0 test fuel owing to the higher heating value of F0. On the other hand, duration in ignition delay (ID) of fusel oil-diesel blends was longer than that of F0 due to the lower cetane number of the fusel oil. The maximum in-cylinder pressure (CPmax) and maximum heat release rates (HRRmax) of fusel oil containing fuels is higher in comparison with diesel fuel owing to the longer ID and oxygen atoms of excessive fusel oil. The combustion characteristics of fusel oil-diesel blends closely followed those of neat diesel fuel.Öğe The history of greenhouse gas emissions and relation with the nuclear energy policy for Turkey(Taylor & Francis Ltd, 2021) Agbulut, Umit; Ceylan, Ilhan; Gurel, Ali Etem; Ergun, AlperThe globalising world, rapidly developing technology and growing population have brought many problems and led to disrupting the world ecological balance. Today, existing energy sources reached such a level that cannot meet the current needs of the world. Due to the fact that fossil fuels will run out in near future, it has made mankind tending to seek alternative energy sources. The main issues addressed in this paper are the history of greenhouse gas emissions (GHGe) and relations with nuclear energy policy, particularly in Turkey. Currently, nuclear has much less GHGe and high energy-efficiency, and also meets 10.6% of the world primary electiricty energy demand. Therefore, countries seriously began to evaluate nuclear energy instead of fossil-fuels. In line with this, Turkey started to build third nuclear plants and aims to meet at least 15% of its primary electiricity energy demand. Hereby, Turkey is not only reducing dependence on fossil-fuels but also planning to reach the undertaken GHGe level as a country of signed the Kyoto protocol.Öğe Impact of various metal-oxide based nanoparticles and biodiesel blends on the combustion, performance, emission, vibration and noise characteristics of a CI engine(Elsevier Sci Ltd, 2020) Agbulut, Umit; Karagoz, Mustafa; Saridemir, Suat; Ozturk, AhmetWith the burning of 1 L of diesel fuel, approximately 3 kg of greenhouse gas is released into the atmosphere. Therefore, it is of great importance to reduce emissions with some additives in diesel engines. This study deals with the impacts of blends of waste cooking oil methyl ester and various metal-oxide based nanoparticles on the emission, combustion, performance, vibration and noise characteristics of a single-cylinder diesel engine. The test engine was loaded at different engine loads of 2.5, 5, 7.5 and 10 Nm and a constant engine speed of 2000 rpm. In this investigation, various fuels [called as reference diesel (D100), 10 vol% of waste cooking oil methyl ester (B10), and finally the mass fractions of 100 ppm aluminium oxide (B10Al(2)O(3)), titanium oxide (B10TiO(2)) and silicon oxide (B10SiO(2)) into the B10, separately] were tested. The addition of metal-oxide based nanoparticles has firstly increased the viscosity, cetane number, and heating value of biodiesel. Higher oxygen atoms in biodiesel-nanoparticles blends have improved the quality of the combustion process. Higher peak point in CPmax and HRRmax could be reached in these nano fuels due to their lower cetane numbers than that of D100. CO, HC and NOx emissions were significantly reduced with the blending of nanoparticles and biodiesel in comparison with those of D100. The addition of nanoparticles highly improved engine performance. B10 had the lowest thermal efficiency due to its heating value, but its efficiency was converted to the highest one with the addition of nanoparticle. In conclusion, this study is suggesting that the addition of metal-oxide based nanoparticles into biodiesel blends can give better results than using biodiesel alone for diesel engines.Öğe Performance analysis of using CuO-Methanol nanofluid in a hybrid system with concentrated air collector and vacuum tube heat pipe(Pergamon-Elsevier Science Ltd, 2019) Kaya, Metin; Gurel, Ali Etem; Agbulut, Umit; Ceylan, Ilhan; Celik, Selim; Ergun, Alper; Acar, BahadirAn experimental study was conducted to determine the effects of adding copper oxide (CuO) with 50 nm diameter into neat methanol (CH3OH) on the energetic and exergetic analysis of a concentrated air collector with vacuum tube heat pipe at different air velocities (1, 2 and 3 m/s). The experimental results clearly indicated that the nanofluid application enhanced the thermal properties and provided better performance for heat pipe applications. Considering all air velocities together, the average efficiency for neat methanol and CuO-Methanol nanofluid was achieved by 65% and 64%, respectively. Additionally, the average specific exergy outlet values for neat methanol and CuO-Methanol nanofluid were calculated as 206 J/kg and 298 J/kg, respectively. In the experiments, it is seen that the efficiency values of the system using the CuO-Methanol nanofluid reached higher values, as the solar radiation values were higher. In conclusions, this paper distinctly suggests that the presence of copper oxide in the base fluid can be used in a concentrated air collector with vacuum tube heat pipe particularly at the high radiation conditions and positively affects the performance of the system.Öğe Performance assessment of a novel design concentrated photovoltaic system coupled with self-cleaning and cooling processes(Wiley, 2020) Acar, Bahadir; Gurel, Ali Etem; Ergun, Alper; Ceylan, Ilhan; Agbulut, Umit; Can, AliThe generation of electrical energy with photovoltaic modules is a highly useful and environmentally friendly method. For this reason, studies to increase the electrical energy production from photovoltaic (PV) modules have gained great importance. Concentrated PV systems constitute a significant part of these studies. The major problems with the concentrated PV systems are the risks of lowering the efficiency of the cells (i.e., concentration process increases PV cell temperature) and the thermal damage that can occur with sudden temperature increases. In order to avoid these risks, various applications are used to cool concentrated PV modules. In this study, an active system, which was developed for cleaning and cooling PV modules, was tested. The aim of the present study was to ensure that the surfaces were clean and free of external, contaminating factors such as dust and dirt, and that the PV cells were cooled. During the experiments, two different systems were compared: the system with the cleaning-cooling processes and the one without these processes. Prior to starting experiments, a hydrophobic liquid onto the surfaces of the PV modules was applied to facilitate the cleaning process. The results of the experiments revealed that the temperature of the PV module was 50 degrees C in the cleaning-cooling process and 67 degrees C in the system without the cleaning-cooling process. On the other hand, it was observed that the proposed design increased the power output of PV module up to 40%.
