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Öğe Experimental investigation of the effect of fuel injection advance on engine performance and exhaust emission parameters using canola oil methyl ester in aturbocharged direct-injection diesel engine(2009) Ileri E.; Kocar G.This paper presents the effect of fuel injection advance on engine performance and exhaust emission parameters using a diesel engine running on canola oil methyl ester (COME). COME was produced and tested at full load with various engine speeds by changing fuel injection advance in a turbocharged directinjection (TDI) diesel engine with four cycles and four cylinders. According to engine performance test results, maximum brake torque (228.2 Nm), brake power (80.3 kW), and thermal efficiency (39.77%) and minimum brake-specific fuel consumption (226.24 g kW-1 h-1) have been obtained for COME on early fuel injection advance (18° crank angle). In addition, early fuel injection advance for O2 and CO but late fuel injection advance (12° crank angle) for NOx and CO2 must be preferred for decreasing exhaust emissions. Exhaust gas temperatures and smoke density increased by an average of 0.33 and 2.69%, respectively, for early fuel injection advance, and these are increased by an average of 1.48 and 13.66%, respectively, for late fuel injection advance. Copyright © 2009 American Chemical Society.Öğe Foresight analysis of wind power in Turkey(2012) Celiktas M.S.; Kocar G.The Turkish wind energy industry is one of the most competitive and fastest growing industries in the energy sector. Industrial energy demands, Kyoto agreement and carbon trade are shown as probable causes. Currently, Turkey has a total installed capacity of about 48.5GW for electricity from all energy sources. High energy prices and unstable suppliers have stimulated Turkey's growing interest in wind business and wind power. This paper analyzes Turkey's wind energy future perspective and power generation strategy with a view to explaining Delphi approach to wind energy development. In this study, the two-round Delphi survey was conducted by experts to determine and measure the expectations of the sector representatives through online surveys where a total of 70 experts responded from 24 different locations. The majority of the Delphi survey respondents were from 23 different universities (60%), electricity generation industries (21%), two different governmental organizations (11%), nongovernmental organizations (6%) and other institutions (2%). The article discusses not only the expert sights on wind energy technology but also all bibliometrical approaches. The results showed that Turkey's wind power installed capacity is expected to exceed 40GW by the end of the 2020s and in the middle of the 2030s, and Turkey would be the European leading country in the field of electricity generation from the wind. © 2011 John Wiley & Sons, Ltd.Öğe Hydrogen is not an utopia for Turkey(2010) Celiktas M.S.; Kocar G.The aim of this study was to explore how the future of technological developments in hydrogen will be shaped in Turkey by using a two-round Delphi method undertaken to determine and measure the expectations of the sector representatives through online surveys where a total of 60 experts responded from 18 different locations. The article discusses not only the expert sights on hydrogen technologies but also all bibliometrical approaches. The results showed that the hydrogen economy will enhance innovations as well as economic prosperities with the support of appropriate policies. Formulating such policies requires a timely and detailed understanding of the latest R&D trends and developments in science and technology policy in all developed countries, and the comprehensive analysis of these developments to enable accurate predictions of future science and technology trends. Therefore, we hope that this study can shed a light on the future use of hydrogen technologies, especially for policy makers. © 2009 Professor T. Nejat Veziroglu.Öğe Improving stability of torrefied biomass at cooling stage(Elsevier Ltd, 2020) Kutlu O.; Kocar G.Torrefied biomass, which has better fuel properties than the crude biomass is used as intermediate product for co–firing and gasification with coal. The stability of torrefied biomass, especially moisture content, deteriorates during direct cooling stage of the production process in case of sub-optimal operating conditions and condensation of liquids onto the solid. In this study, three operating parameters of direct cooling stage were optimised statistically with operating cost to produce a stable torrefied biomass. Their effect on the moisture content and final temperature of product was thoroughly investigated in this study. Furthermore, the temperature distribution in the cooling chamber was examined by using a thermal imaging camera. Even though the coolant flow rate played a more prominent role only for product properties and operating cost, the residence time was more effective parameter for cooling. The optimisation results indicated that the stability of torrefied biomass having similar properties with lignite could be improved by using the speed of 2.87 rpm and a residence time of about 20 min at nitrogen flow rate of 4 l/min. The minimum operating cost was calculated when there was a deviation of 20.7% from target product quality. © 2019 Elsevier LtdÖğe The potential of biogas energy(2005) Acaroglu M.; Kocar G.; Hepbasli A.Biogas technology has been known about for a long time, but in recent years the interest in it has significantly increased, especially due to the higher costs and the rapid depletion of fossil fuels as well as their environmental considerations. The main objective of the present study is to investigate the potential of biogas energy in the 15 European Union (EU) countries and in Turkey, which is seeking admission to the EU and is trying to meet EU environmental standards. Biogas energy potential of the 15 EU countries is estimated to be about 800 PJ. Besides this, Turkey's annual animal waste potential is obtained to be about 11,81 million tons with a biogas energy equivalent of 53.6 PJ. It is expected that this study will be helpful in developing highly applicable and productive planning for energy policies towards the optimum utilization of biogas energy.
