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Öğe Adyabatik soğutma sistemlerinde nozul yapısının soğutma performansına etkilerinin teorik ve deneysel incelenmesi(2016) Gürel, Ali Etem; Yıldız, Abdulaziz; Deniz, EmrahKüresel ısınma, yaşam standartlarındaki artış vb. etkenler soğutma ve iklimlendirme sistemlerine olan talebi her geçen gün artırmaktadır. Bu sistemlerin performanslarının artırılmasına yönelik farklı yöntemler kullanılmaktadır. Bu yöntemlerden biri de soğutma sistemlerinde evaporatif kondenser kullanımıdır. Bu çalışmada, soğutma sistemlerinde evaporatif kondenser kullanımının sistem performansına olan etkileri deneysel olarak analiz edilmiştir. Deneysel sistemin kondenser ünitesi adyabatik nemlendirme yöntemi ile soğutulmuştur. Adyabatik nemlendirme işlemi 0.2, 0.3 ve 0.4 mm çaplarında nozullar kullanılarak gerçekleştirilmiştir. Sistem, hava soğutmalı kondenser kullanımı ve farklı nozul çapları için termodinamik olarak analiz edilmiş, sistemin soğutma performansları karşılaştırılmıştır. Elde edilen veriler evaporatif kondenser kullanımıyla, kompresör işinde %8.48 azalma, soğutma sistemi COP değerinde %32.92 ve tüm sistemin COP değerinde ise, %18.43 artış olduğunu göstermiştirÖğe Biogas engine performance estimation using ANN(Elsevier - Division Reed Elsevier India Pvt Ltd, 2017) Kurtgoz, Yusuf; Karagoz, Mustafa; Deniz, EmrahArtificial neural network (ANN) method was used to estimate the thermal efficiency (TE), brake specific fuel consumption (BSFC) and volumetric efficiency (VE) values of a biogas engine with spark ignition at different methane (CH4) ratios and engine load values. For this purpose, the biogas used in the biogas engine was produced by the anaerobic fermentation method from bovine manure and different CH4 contents (51%, 57%, 87%) were obtained by purification of CO2 and H2S. The data used in the ANN models were obtained experimentally from a 4-stroke four-cylinder, spark ignition engine, at constant speed for different load and CH4 ratios. Using some of the obtained experimental data, ANN models were developed, and the rest was used to test the developed models. In the ANN models, the CH4 ratio of the fuel, engine load, inlet air temperature (T-in), air fuel ratio and the maximum cylinder pressure are chosen as the input parameters. TE, BSFC and VE are used as the output parameters. Root mean square error (RMSE), mean absolute percentage error (MAPE) and correlation coefficient (R) performance indicators are used to compare measured and predicted values. It has been shown that ANN models give good results in spark ignition biogas engines with high correlation and low error rates for TE, BSFC and VE values. (C) 2017 Karabuk University. Publishing services by Elsevier B.V.Öğe Comparative examination of vacuum insulation panels and classical insulation materials used for external insulation of buildings(Sila Science, 2012) Deniz, EmrahIn this study, the usability of Vacuum Insulation Panels (VIP) was assessed by determining the optimum insulation thickness and associated fuel costs, insulation costs, total costs, energy gain, and payback periods of four conventional insulation materials and VIPs which are applied in four different cities in four different climate regions of Turkey. Calculations were done by lifetime cost analysis (LCCA). Payback periods were calculated for five different energy source and the amount of energy saving were calculated for a 10-year service period. The results show that the conventional insulation materials provide significant energy saving in all four climate regions and pay back in about two years. On the other hand, the energy saving and payback periods of VIPs changes significantly by the energy source used and the climate of the region. VIPs offers a significant energy saving and have a time of payback period of as low as two years in regions where the fuel unit cost and heating degree day number are high. However it is not reasonable to use VIPs where the unit cost of fuel and heating degree day number are low since it requires a long time to payback.Öğe The effect of the CO2 ratio in biogas on the vibration and performance of a spark ignited engine(Elsevier Sci Ltd, 2018) Karagoz, Mustafa; Saridemir, Suat; Deniz, Emrah; Ciftci, BurakBeing a renewable fuel, biogas can be produced either through anaerobic digestion from animal manure, inedible seed residue, food waste, agricultural waste, domestic waste and sewage sludge or through thermo-chemical processes. Along with thermal applications, by means of combustion inside an engine, biogas can produce both mechanical and electric energy. Depending on the inertia forces of the active parts and the characteristics of the in-cylinder combustion of the engine, vibration can be quite a big problem because it leads to rapid breakdown of engine parts, noisy operation and decreased performance and power output. The CO2 in biogas is an important compound that affects its lower heating value (LHV), burning characteristics and exhaust emissions. There are a limited number of studies in the literature on the effect of biogas CO2 content on engine vibration. In the present study, a four-cylinder diesel engine was modified to operate with a spark plug and used to detect the effect of the biogas CO2 content on the vibration of the engine. The experiments were carried out with biogas containing 13% and 49% CO2 at 1.5-9 kW with 1.5 kW load increments at a steady 1500 rpm speed. The amplitude of the engine vibration at all three axes increased as the CO2 ratio in the biogas and the engine load increased. On the other hand, by decreasing the CO2 ratio and increasing the engine load, cylinder pressure increased and brake specific fuel consumption decreased. The highest amplitude of engine vibration for all loads was observed at the lateral axis.Öğe Energy and exergy analysis of flat plate solar collector-assisted active solar distillation system(Taylor & Francis Inc, 2016) Deniz, EmrahDue to the fast increase in the world population, the need for the energy and water increases rapidly. Various studies have been made to meet this extra energy and water demand. Most of these studies have focused on solar energy and solar driven desalination systems. Solar water desalination is a well-known and proven technique which has been used for a long time at remote areas and places suffering from shortage of potable quality water. In this study, a flat plate solar collector-assisted water distillation system was designed and tested under actual conditions and its energy and exergy efficiencies were analyzed, which is the main contribution of this study to the literature related to solar desalination systems. The system works under closed cycle in order to prevent efficiency losses caused by internal fouling in both solar collector and distillation unit. The maximum daily energy efficiency of the system was obtained as 48.1% and the maximum exergy efficiency was found as 2.76% for optimum flow rate values.Öğe Energy, exergy, economic and environmental (4E) analysis of a solar desalination system with humidification-dehumidification(Pergamon-Elsevier Science Ltd, 2016) Deniz, Emrah; Cinar, SerkanA novel humidification-dehumidification (HDH) solar desalination system is designed and tested with actual conditions and solar energy was used to provide both thermal and electrical energy. Energy-exergy analyses of the system are made and economic and enviro-economic properties are investigated using data obtained from experimental studies. In this way, economic and environmental impacts of the HDH solar desalination systems have also been determined. The maximum daily energy efficiency of the system was calculated as 31.54% and the maximum exergy efficiency was found as 1.87%. The maximum fresh water production rate is obtained as 1117.3 g/h. The estimated cost of fresh water produced through the designed HDH system is 0.0981 USD/L and enviro-economic parameter is 2.4041 USD/annum. (C) 2016 Elsevier Ltd. All rights reserved.Öğe Environmental pollution cost analysis of a diesel engine fueled with biogas-diesel-tire pyrolytic oil blends(Elsevier - Division Reed Elsevier India Pvt Ltd, 2021) Tunc, Nuri; Karagoz, Mustafa; Ciftci, Burak; Deniz, EmrahFuels obtained from waste in seeking of sustainable and environmentally friendly fuel are promising for internal combustion engines. In this study, an environmental pollution cost analysis was performed for a diesel engine fueled with blends of pyrolytic oil - biogas - neat diesel fuel. Five different test fuels were studied. Neat diesel fuel (DF), the fuel mixture prepared by blending 10% pyrolytic oil to 90% neat diesel fuel by volume (DF90P10). While the DF90P10 fuel was supplied to the engine from the injector, the experiments were carried out with different fuel combinations created by delivering gaseous biogas at constant flow rates of 1, 3 and 5 L/min from the intake manifold (DF90P10B1, DF90P10B3, DF90P10B5). The experiments were carried out in a single-cylinder, air-cooled, direct injection diesel engine, with a constant engine speed of 3000 rpm and four different engine loads ranging from 0.25 to 1 kW, with prepared fuel blends. Fuel consumption, exhaust emissions, exhaust and engine block temperatures were measured to make environmental pollution cost analysis. In these tests, it was found that the DF90P10B1 test fuel performs better results as compared to those of neat diesel fuel which is reference fuel and other test fuels in terms of environmental pollution cost analysis. Pyrolytic oil - biogas - diesel fuel mixtures in variable ratios, can be used as an alternative fuel instead of neat diesel in diesel engines without any engine modifications. (C) 2020 Karabuk University. Publishing services by Elsevier B.V.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 AN EXPERIMENTAL INVESTIGATION OF BIOGAS PURIFICATION WITH GRANULATED SLAG UNDER DIFFERENT PRESSURES(Health & Environment Assoc, 2017) Karagoz, Mustafa; Tunc, Nuri; Ciftci, Burak; Deniz, EmrahBiogas, with its production and energy potential, is an important renewable energy source for the developing renewable energy market. Biogas is a type of fuel that is produced from the biochemical degradation of biomass. It has a density similar to oxygen and before the biogas can be used, it is necessary to remove the contaminant gas content. Biogas is a gas obtained by degradation of biological wastes in an anaerobic environment. The contaminants in the biogas can decrease the lower heating value of the fuel and also cause corrosion and rust in the equipment and components used. Therefore, before using biogas, it is necessary to remove contaminants in it. In this study, biogas has been produced from animal waste by co-fermentation method. In order to purify the produced biogas from the pollutant gases, the effect of granular slag (an iron steel plant waste) in H2S removal from the biogas, has been investigated experimentally for different pressures. Experiment results gave an average amount of biogas production of 1.6 m(3) / day and methane (CH4) content reaching up to 71%. At the end of the process, it was determined that the 278 ppm H2S value of the biogas measured before entering the purification tower with slag material was purified with a ratio of 31% and decreased to 192 ppm without significant loss of methane.Öğe An experimental study on a novel defrosting method for cold room(Pergamon-Elsevier Science Ltd, 2021) Abdulla, Mahade Omran Ali; Deniz, Emrah; Karagoz, Mustafa; Guruf, GursahRefrigeration systems can be blocked by frost accumulating on the evaporator, when they operate at a temperature below the dew point of air and the freezing point of water. Therefore, a defrost process that consumes extra energy needs to be started from time to time. Conventional defrosting methods require energy and time to complete, which reduce the refrigeration efficiency and cause a temperature fluctuation in the storage room during the defrosting process. In this study, a new type of defrosting is used in order to reduce the energy needed for defrosting, improve refrigeration efficiency and decrease temperature fluctuations, which utilize the heat from the liquid refrigerant to defrost the evaporator using two evaporators and a four-way valve. When one of the evaporators cools the room, the other is used for sub-cooling the refrigerant before entering the cooler evaporator. The sub-cooling process provides defrosting of the second evaporator. When the cooler evaporator requires defrosting, the four-way valve reverses the cycle, and the second evaporator becomes cooler. The first evaporator then becomes the sub-cooler to be defrosted. A cold room with this concept was built and tested experimentally together with a conventional cooling system. Energy, exergy, economic and environmental (4E) analyses of both systems were made and the results were compared. The results show that the new method can perform the defrosting process using the energy dissipated from the sub-cooling refrigerant without using any external power source and improve refrigeration efficiency by 12%. Moreover, this new system does not interrupt the cooling process during defrosting process as the conventional systems do. Temperature fluctuations also decrease by about 60% following this method.Öğe Global solar radiation estimation using artificial neural network by the addition of nearby meteorological stations' solar radiation data and exergy of solar radiation: a case study(Inderscience Enterprises Ltd, 2016) Kurtgoz, Yusuf; Deniz, EmrahThe artificial neural networks (ANNs) can be used to accurately predict the global solar radiation (GSR). There are many geographical, meteorological and terrestrial parameters affecting GSR. In this study, the most relevant of six input parameters are selected to predict the GSR of Goksun Station in Turkey using Waikato environment for knowledge analysis (Weka) Software. The effect of using nearby meteorological stations' GSR data as input on GSR prediction is investigated. Different ANN models are developed to demonstrate the difference between the exclusion and inclusion of these parameters on the model. The results show that the exclusion of less influential parameters and the inclusion of three nearby stations' GSR data has improved performance criteria. Petela, Spanner and Jeter's approaches are used for exergy analysis of measured and estimated GSR values. The mean exergy-to-energy ratio for both Petela and Spanner's approaches is 0.934, while Jeter's approach showed 0.950.Öğe Güneş ışınım şiddeti tahminlerinde yapay sinir ağları ve regresyon analiz yöntemleri kullanımının incelenmesi(2007) Deniz, Emrah; Atık, KemalYapılan çalışmada, yapay sinir ağları ve regresyon analiz yöntemlerinin güneş ışınım şiddeti tahmini amacıyla kullanımında hangi yöntemin daha etkin olduğu araştırılmıştır. Bu amaçla, Zonguldak iline ait 1995 ile 2004 yılları arasındaki aylık ortalamalar halinde on yıllık rüzgâr hızı, hava sıcaklığı, toprak sıcaklığı, deklinasyon açısı, nem miktarı, güneş ışınımı alımının gün uzunluğuna oranı ve aylık ortalama atmosfer dışı güneş ışınım şiddeti verileri Devlet Meteoroloji İşleri Genel Müdürlüğünden (DMİGM) temin edilmiştir. Alınan veriler düzenlenerek regresyon analiz yöntemi ve yapay sinir ağları (YSA) yardımıyla modeller elde edilmiştir. Bu modeller kullanılarak Ocak/2005 ve Aralık/2005 arasındaki toplam güneş ışınımının aylık ortalamaları hesaplanmış ve 2005 yılında ölçülmüş olan veriler ile karşılaştırılmıştır. Ölçülen değerler ile hesaplanan değerler arasında regresyon analiz yöntemleri kullanıldığında % 1.28, yapay sinir ağları kullanımında ise % 3.25’lik bir ortalama bağıl hata olduğu belirlenmiştir.Öğe An Investigation into the Effects of Box Geometries on the Thermal Performance of Solar Cookers(Taylor & Francis Inc, 2008) Kurt, Huseyin; Deniz, Emrah; Recebli, ZiyaddinThe effect of box geometry, such as cylindrical and rectangular, on the performance of solar cookers has not been investigated. In this study, two different model box type solar cookers, which are in rectangular and cylindrical geometries, were constructed using the same material and were tested to investigate the effects of box geometries on the cooker performance. The experimental studies were conducted under the same operating conditions. The obtained results from the experiments were used to calculate the thermal efficiency and specific and characteristic boiling times. These parameters of the cookers were determined for 0.5, 1, and 1.5 kg of fresh water. It is observed that the cylindrical model has higher temperatures than the rectangular model under the same operating conditions. The thermal efficiency increased from 12.7 to 36.98% for cylindrical and 9.85 to 28.25% for rectangular model, when the quantity of water was increased from 0.5 to 1.5 kg; similarly, the characteristic boiling time was decreased from 39.56 to 14.35 for the cylindrical and 43.74 to 15.77 (min m-2 kg-1) for the rectangular model, respectively. The cylindrical model provided high thermal performance, which is indicated by high thermal efficiency and low characteristic boiling time, in comparison with the rectangular model.Öğe An investigation of some of the parameters involved in inclined solar distillation systems(Wiley-Blackwell, 2013) Deniz, EmrahThere are two main problems of inclined solar water distillation systems. There is not a water film layer enough to facilitate the evaporation of water on the absorber plate, and high temperature of glass cover decreases the amount of condensed water. In this article, an inclined solar water distillation system was designed and tested under actual environmental conditions of Turkey in order to overcome these two main problems. Therefore, with this study, improving of inclined solar water distillation system performance was investigated. The system was tested with four variants: bare plate (BP), shaded bare plate (SBP), black-cloth wick (BCW), and shaded black-cloth wick (SBCW). Experimental studies showed that the use of bare cloth wick, shading plate, and both together increase the system efficiency by 3, 2, and 5% respectively. (c) 2012 American Institute of Chemical Engineers Environ Prog, 32: 350-354, 2013Öğe Investigation of using regression analysis and artificial neural network methods in estimate of solar radiation(Turkish Soc Thermal Sciences Technology, 2007) Deniz, Emrah; Atik, KemalIn this study, the more effective one of two methods, artificial neural network and regression analysis, was tried to be determined when they were used in estimation of the solar radiation intensity. For this purpose, wind velocity, air temperature, soil temperature, declination angle, humidity, the ratio of solar irradiation to daytime length, and monthly average of extraterrestrial solar radiation data between 1995 and 2004 belonging to Zonguldak city was obtained from Turkish State Meteorological Service (TSMS). Models were developed by regression analysis and artificial neural network (ANN) with the data obtained. Using these models, mountly average values of total solar irradiation between January/2005 and December/2005 were calculated and these calculated results were compared to measured results of the same period. It was determined that there are mean relative errors of 1.28 % and 3.25 % when the estimation was made by regression analysis and artificial neural network respectively.Öğe Performance parameters estimation of MAC by using artificial neural network(Pergamon-Elsevier Science Ltd, 2010) Atik, Kemal; Aktas, Abdurrazzak; Deniz, EmrahIn this study, a modeling of a mobile air conditioner system in different amounts of refrigerant and in different compressor revolution speeds was carried out via artificial neural network (ANN). The three-layered ANN that is utilized in order to be able to model this system has 2 cells in its input layer and 3 cells in its output layer. The least problem-yielding ANN structure was analyzed by examining the number of cells in hidden layer from 6 to 19. The best result was obtained in the ANN with 10 hidden cells. A 0.945 was obtained in estimating coefficient of correlation cooling capacity, 0.985 was found in the power consumed in compressor, and 0.994 was established in COP estimation. The obtained correlation coefficients showed that ANNs can be used with a high precision in guessing the performance parameters of mobile air conditioner (MAC) systems. (C) 2010 Elsevier Ltd. All rights reserved.Öğe Solar radiation exergy and enviroeconomic analysis for Turkey(Inderscience Enterprises Ltd, 2017) Kurtgoz, Yusuf; Deniz, Emrah; Turker, IlkerThe knowledge of useful solar energy amount is important for designing solar energy systems. In this study, solar radiation exergy (SRE) values are calculated for the 81 cities in Turkey. The data are obtained from the General Directorate of Renewable Energy and the General Directorate of Meteorology. The approaches of Petela, Spanner and Jeter are used to calculate the exergy-to-energy ratios for determining the maximum utilisable solar radiation energy. The exergy-to-energy ratios, the SRE values, the locations having the highest solar exergy potential and the monthly, seasonal and annual total SRE maps are presented for Turkey. Finally, enviroeconomic analysis is performed and its results are presented. The available results are visualised via maps with colourbars.Öğe Solar thermal waste heat energy recovery in solar distillation systems by using thermoelectric generators(Elsevier - Division Reed Elsevier India Pvt Ltd, 2023) Ozcan, Yasin; Deniz, EmrahIn this study, the novel use of thermoelectric technology in solar desalination systems was experimen-tally investigated. The new type of solar still with the thermoelectric generator (CSS-TEG) was proposed to improve the water output and efficiency. CSS-TEG's performance was assessed and compared with the conventional one (CSS). Economic and enviro-economic assessments, as well as energy and exergy anal-yses, were conducted based on the system parameters and measurements taken from the designed experimental setup. The new system's daily energy and exergy efficiency were obtained as 40.34% and 2.462% respectively, whereas, with the CSS one, they were 35.55% and 2.403%, respectively. The daily pro-duction of distilled water from the CSS and the newly designed solar still with TEG was measured at 4313 g/m2 and 4893 g/m2, respectively. In general, the estimated production cost of 1 kg of freshwater from CSS was 0.055$, and CSS-TEG was 0.081$. Additionally, referring to the exergo-economic parameter, CSS and CSS-TEG mitigated an average of 0.596 and 0.6132 tons of CO2 respectively. (c) 2023 Karabuk University. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Öğe A STUDY ON THE DETERMINATION OF ANIMAL-BASED BIOGAS ENERGY POTENTIAL OF TURKEY(Agronomski Fakultet Sveucilista U Zagrebu, 2011) Deniz, Emrah; Polat, Refik; Gurel, Ali Ethem; Camur, DoguEnergy is the basic input of social and economic development in Turkey and throughout the world. Global energy need is gradually increasing with population growth and industrialization. The widespread use of renewable energy sources in meeting this need is of great importance in economic and environmental terms. Due to its advantages of sustainability, availability and environmental friendliness, animal and plant based biogas production has been analyzed intensively in recent years. This study determined the number of large ruminants, small ruminants and poultry animals within Turkish provinces in 2009. Animal based biogas potential was calculated and the current status of this technology was analyzed. The electrical energy and natural gas energy equivalent of biogas production potential fur 2009 was determined. It was found that 9.4% of total electrical consumption and 4.4% of natural gas consumption of Turkey could be supplied from biogas. In addition, the animal based biogas potential of Turkey during the last 19 years was determined and, based on this data, future biogas potential was analyzed.
