Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Optimization of a Hybrid Combination of a Photovoltaic Syste and a Wind Energy Conversion System: Izmir Institute of Technology Campus Area Case(Izmir Institute of Technology, 2003) Ekren, Orhan; Özerdem, Mehmet BarışRenewable energy resources have gained the great importance due to the growing concerns of environmental problems. The integrated utilization of renewable energies such assolar and wind are becoming very attractive, especially, in most of the isolated and remote areas in many parts of the world.In the present study, firstly, wind and solar radiation measurements, made on Izmir Institute of Technology (IZTECH) Campus area, have been analyzed in order to determine the, both, solar and wind energy potentials of the location. The monthly average wind speeds range from 5.7 m/s to 7.7 m/s, the monthly average of daily values of solar radiation range from 2.1 kWh/m2 to 5.7 kWh/m2 at the monitoring station throughout the measurement period of 12 months between 01.01.2002 and 31.12.2002.Secondly, a procedure is described which determines the hybrid system parameters such as photovoltaic (PV) array area and rotor swept area of wind turbine while satisfying a specific load distribution. The employed method is a graphical construction to figure out the optimum configuration of the generators that satisfies the energy demand mentioned above.Master Thesis Optimization of Lamella Burner Fin Deck(Izmir Institute of Technology, 2007) Çetin, Gökçe; Özerdem, Mehmet BarışLamella burner is a low NOx burner patented by BOSCH Thermotechnologies.In this study, different designs of fin deck, which is one of the major components of the lamella burner, are experimentally analyzed and optimized. After the optimization process, a numerical analysis was used for verification.Emissions are the most important properties for the gas fired boilers and directly related with the design of the burner parts where the combustion occurs. In the lamella burner, fin deck is the most related part with combustion. Combustion occurs on the fin deck surface hence, current fin deck design analysis and optimization is based on the emission rates in order to keep the lamella burner as low-emission (both NOx and CO)burner.This study mainly consists: summary of main parameters regarding combustion and fin deck, experimental analysis, and verification of optimized fin deck model with numerical simulation. Firstly, gas combustion and lamella burner are investigated. Physical conditions and combustion characteristics for fin deck are analyzed and layout parameters for fin deck are deducted. Afterwards, four new fin deck designs are introduced as alternatives for the current design. In the experimental part, emission, light back, flame lift, temperature and pressure drop tests are performed for serial and each new sample in the BOSCH Product Development Laboratories, Manisa. According to the test results, the most preferred sample is defined as optimized one.Test results are discussed to explain whether the fin deck samples are preferable or not. In the combustion curve performance test, CO values are measured. The comparison between the combustion curve test results show that CO formation is related to the fin deck geometry. Geometry affects flame stability because of the differences in mixture velocity distributions. The unburned gas in exhaust is one of the causes of the CO formation and influenced from the flame stability. Therefore,unburned gas mass fractions in exhaust are different for the samples with different geometries. This result is also numerically verified in combustion simulations of two different fin deck models, which one of them is considered as optimized sample.Master Thesis An Experimental Study on Enhancement of Heat Transfer in a Solar Air Heater Collector by Using Porous Medium(Izmir Institute of Technology, 2012) Maraba, Gizem; Özerdem, Mehmet BarışThe aim of this thesis is to enhance the heat transfer of a solar air heater by using porous material. A comprehensive literature survey has been carried out to learn the previous researches. Depending on this literature survey, some design parameters were determined and a solar air heater was constructed to the Solar & Wind Energies Laboratory according to this parameters. In order to obtain the optimum design parameters and maximum efficiency of solar air heater, several studies have been carried out including clear and porous material assisted channels. For this purpose different configurations and designs were investigated and tested. Temperature data along the collector, average velocity of air inside the channel, pressure drop due to the porous material, power that fan and electrical heater consumes were measured and tabulated regularly. Related graphs were drawn according to the experimental results. The effect of porous material on the heat transfer and collector efficiency was discussed based on these graphs.Master Thesis Comouter-Aided Aerodynamic Design of Small Scale Horizontal Axis Wind Turbine Blades(Izmir Institute of Technology, 2012) Göçmen, Tuhfe; Özerdem, Barış; Özerdem, Mehmet BarışIn this thesis, aerodynamic design of 1, 5, 10, 25, 50, 100, 250 and 500 kW horizontal axis wind turbine generators has been performed. The design procedure starts with the design and analysis of airfoils done by programs of PROFOIL and XFOIL, respectively through which the structural, aerodynamic and aeroacoustic principles have been taken into consideration. Then, the performance parameters of designed profiles were inputted to the constructed modified blade element momentum theory (BEM) code together with the main design parameters in order to obtain 3D blade geometry. The code is validated using MIE wind turbine with a rated power of 8 kW. The generated blade geometries are then analyzed using commercial computational fluid dynamics CFD code Numeca FINEâ„¢/Turbo and the velocity and pressure distributions around the blade have been visualized, separately. Moreover, the power coefficient, Cp was calculated and the power curves of the designed wind turbine rotors were drawn.Master Thesis A Feasibility Study and Evaluation of Financing Models for Wind Energy Projects: A Case Study on Izmir Institute of Technology Campus Area(Izmir Institute of Technology, 2004) Özer, Serra; Özerdem, Mehmet BarışFeasibility studies have been done for different scenarios on IZTECH campus area where previous wind data evaluation showed considerable wind potential. RET Screen software has been used for feasibility calculations. Internal rate of return and unit cost of energy have been examined for the proposed scenarios. First scenario represents an autoproducer model which would meet IZTECH.s electricity need. Two 600 kW turbines were used in this scenario and the unit cost of energy have calculated as 24 cents/kWh.Second scenario represents an autoproducer group. Two units with 900 kW rated power turbines were used in the scenario and 4.82 cents/kWh is found as unit energy cost. Finally, third and last scenario is planned as production plant with thirteen 900 kW turbines. The energy unit cost would be 2.68 cents/kWh when scenario is applied. This study showed that IZTECH campus area which was inspected before for wind data characteristic and technical potential point of view, found economically viable too. Within the finance models, project finance and syndicated loan credit were examined as the most convenient mechanisms.Master Thesis A Mathematical Model of the Human Thermal System(Izmir Institute of Technology, 2005) Yıldırım, Eda Didem; Özerdem, Mehmet BarışMathematical model of the human thermal system, which has been greatly developed in recent years, has applications in many areas. It is used to evaluate the environmental conditions in buildings, in car industry, in textile industries, in the aerospace industry, in meteorology, in medicine, and in military applications. In these disciplines, the model can serve for research into human performance, thermal acceptability and temperature sensation, safety limits. Present study investigates the mathematical modeling of the passive part of the human thermal system. The Bio-Heat Equation is derived in order to solve the heat transfer phenomena in the tissue and with environment. It is assumed that the body is exposed to combination of the convection, evaporation and radiation which are taken into account as boundary conditions when solving the Bio-Heat Equation. Finite difference technique is used in order to find out the temperature distribution of human body. The derived equation by numerical method is solved by written software called Bio-Thermal. Bio-Thermal, is used to determine temperature distribution at succeeding time step of the viscera, lung, brain all tissue type of the torso, neck, head, leg, foot, arm, hand, and mean temperature of torso, neck, head, leg, foot, arm, hand. Additionally, for overall body, mean temperature of the bone tissue, muscle tissue, fat tissue, and skin tissue and mean temperature of the total body can be obtained by Bio-Thermal Software. Also, the software is to be capable of demonstrating the sectional view of the various body limbs and full human body. In order to verify the present study, predictions of the present system model are compared with the available experimental data and analytical solution and show good agreement is achieved.Master Thesis Investigation of Aerodynamic Effects on Performance of Wind Turbine Blades by Using Finite Element Method(Izmir Institute of Technology, 2005) Tosun, Mehmet Mahir; Özerdem, Mehmet BarışIn this study, design of the most suitable wind turbine rotor for Iztech campus area is performed by taking into account aerodynamic effects.Aerodynamic properties of various airfoils are determined, numerically, by using a software called FLUENT. Blade element momentum theory is applied to find chord lengths and twist angles for mean wind speed at 10m height in Iztech campus area. Rotor performance is determined by using blade element momentum theory. Effects of twist angle and tip speed ratio are investigated for blade design. Rotor maximum power coefficient of the new designed blade is found as 0.4313 while another design in use gives a maximum power coefficient of 0.4044.It can be noted that new designed blade is more efficient, as it gives the maximum power coefficient at design conditions, 6.85 m/s wind speed at 10 m height and 25oC ambient temperature. It is observed that new design gives higher power values than the design in use, over 5.8 m/s wind speed.Master Thesis Analysis of a Hydrogen Fueled Internal Combustion Engine(Izmir Institute of Technology, 2005) Kahraman, Erol; Özerdem, Mehmet BarışIn the history of internal combustion engine development, hydrogen has been considered at several phases as a substitute to hydrocarbon-based fuels. Starting from the 70.s, there have been several attempts to convert engines for hydrogen operation.Together with the development in gas injector technology, it has become possible to control precisely the injection of hydrogen for safe operation. Since the fuel cell needs certain improvements before it is widely used in vehicles, the conventional internal combustion engine is to play an important role in the transition. This study examines the performance characteristics and emissions of a hydrogen fueled conventional spark sparkignition engine. Slight modifications are made for hydrogen feeding which do not change the basic characteristics of the original engine. Comparison is made between the gasoline and hydrogen operation and engine design changes are discussed. Certain remedies to overcome the backfire phenomena are attempted.Master Thesis Measurement and Comparison of Solar Radiation Estimation Models for Izmir/Turkey: Izmir Institute of Technology Case(Izmir Institute of Technology, 2011) Vecan, Didem; Özerdem, Mehmet BarışSolar energy technologies offer a clean, renewable and domestic energy source, and are essential components of a sustainable energy in the future. Proper and adequate information on solar radiation and its components at a given location is very essential in the design of solar energy systems. Due to Turkey’s location, solar energy potential is abundantly available. Consequently, it is worth to examine and conduct research on the solar energy source. In this study, the global solar radiation data in Izmir were analyzed based on 3 years of global solar radiation data measured on a horizontal surface on the campus area of Izmir Institute of Technology. Actual data readings were made on a ten minute basis from January, 2005 to December, 2007. Monthly-average daily global radiation has been analyzed. A linear, a second-order and third order equations are designed for the calculation of the monthly-average daily global radiation in Izmir. The main objective is to estimate global solar radiation via models mentioned in the literature both for Turkey in general and for Izmir specifically; and to compare the results with the three new developed models. In addition to global solar radiation, diffuse solar radiation data were analyzed and proposed models for estimating the monthly average daily diffuse solar radiation, as well. Four new models were developed for diffuse solar radiation calculations and nine models from the literature have been used. In order to confirm the results, four statistical methods have been used namely; mean bias error (MBE), root mean square (RMSE), t-statistic and relative percentage error. According to the statistical evaluation, it may be concluded that the new polynomial equation predict the monthly-average daily global solar radiance better than other available models.Master Thesis Economic Assessment Of Balçova-narlıdere Geothermal District Heating Systems(Izmir Institute of Technology, 2003) Erdoğmuş, Abdullah Berkan; Özerdem, Mehmet BarışDevelopment of a geothermal district heating system covers full range of activities from the determination of geothermal reservoir to the delivery of geothermal energy successfully. Economic assessments are come true in the early stages of geothermal developments. The goal of this thesis is to realize a detailed economic assessment for Balçova-Narlıdere Geothermal District Heating System (GDHS) which is one of the largest district heating systems in Turkey with its current heating capacity of 50 MWth. Tasks in geothermal district heating investments are looked over at the beginning to make a correct economic evaluation and make future development in this geothermal field easy under the discipline of project management. Internal rate of return method which is commonly used financial tool to find the profitability of investments is applied to this investment. The economic analysis begin with the calculation of end of 2002 values of capital investment costs, revenues and operating costs since the existence of past cash flows. Future operating costs are determined according to the yearly expenditures realized in 2002. Future revenues are determined in accordance with the capacity of current heating system and energy utilization prices valid in 2002-2003 heating season. If the sustainability of a resource is considered in the design, the prospective geothermal district heating system could be operated in a long period. However, long-term period projects contain economic uncertainties for the future cash flows. The overall life of Balçova-Narlıdere GDHS is considered as 20 years after year 2001 and uncertainties are considered in this study. Calculations are realized according to various scenarios in which operating costs are constant throughout 20 years. To determine these scenarios, operating costs in 2002 which reflects the current expenditures are either decreased or increased by some percentages. In addition, 60 different pricing plans have been taken into consideration in these scenarios to demonstrate the effects of energy utilization prices on the profitability of investment. The continuity of current price policy for Balçova-Narlıdere GDHS is discussed and energy utilization prices per 100 m2 are suggested for these scenarios. On the other hand, taxes paid to government in Balçova-Narlıdere GDHS investment are investigated to show the benefits of geothermal investments from the viewpoint of government. Because of the development in production of some equipment like heat exchangers, pipes and changing in marketing strategy, the costs of these equipment are reduced. At the end, internal rate of return method is repeated for the current cost of the investment. The energy utilization prices for 13 different scenarios are found for this situation and results are compared with the prices determined to meet the real cost of the investment.