Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Lithiation of Metal-Oxide Thin Film Layers on Zto/Ag Electrodes by Magnetron Sputtering for Electrochromic Devices(Izmir Institute of Technology, 2023) Deveci̇, Enver; Özyüzer, Lütfi̇; Ünal, UğurElectrochromism is a property of materials that undergoes a reversible transition from a colorless or transparent state to a colored state under the action of electric voltage or current. What makes electrochromic materials special is by controlling the voltage applied to the material. Among these electrochromic materials, metal oxides such as WO3 and NiOx are metal oxides that are frequently used. Electrochromic devices are devices that do not consume much energy and can save a lot of energy. A typical electrochromic device consists of five different thin film layers: an ionic conductive layer (electrolyte) and transparent conductive oxides (ZTO, ITO, etc.) are located between the main electrochromic layer and the secondary electrochromic layer.In this study, instead of the traditionally used transparent conductive electrode ITO, ZTO/Ag/ZTO (Z=Zn2SnO4) electrode with high optical transmittance and electrical conductivity was used, thus cost-effective and more efficient electrochromic devices were produced. Here, 3 layers of thin film (WO3,Ta2O5, NiOx) coating on Glass/ZAZ samples was grown by magnetic sputtering method at room temperature and the production parameters were optimized. Here, WO3 and NiOx are used as thin film electrochromic layer, while Ta2O5 is used as solid-state electrolyte. The electrochemical properties of the metal oxide WO3 and NiOx coatings used here were measured in 1 M LiClO4-PC electrolyte using a conventional three-electrode configuration. In the next step, to test the performance of WO3 and NiOx electrochromic films, Li-based liquid electrolyte was mounted on our electrochromic device (ZAZ/NiOx/Ta2O5/WO3/ZAZ), which has a five-layer battery-like structure and tested.Master Thesis Improvement of Indoor Air Quality in Classrooms Based on Age of Air Parameters and Fanger's Predicted Mean Vote Method(Izmir Institute of Technology, 2023) Yetiş, Ahmetcan; Karadeni̇z, Zi̇ya Haktan; Gökçen Akkurt, GüldenIndoor air quality in classrooms is an important research topic today. Studies have shown that poor or inadequate indoor air quality has negative effects on students' performance and active participation in classes. The aim of this study is to examine the local air velocity and air age parameters to determine the ventilation needs of crowded, but limited-sized classrooms that are not connected to a central ventilation system, and to investigate the applicability of ventilation systems that can provide adequate indoor air quality. In the study, a primary school classroom with a capacity of 30 students was examined. Ventilation requirement is determined per person according to "ASHRAE 62.1-2022" Standard and "Building Bulletin 101" directive. For ventilation of the classrooms, counter-fluid heat recovery ventilation units mounted embedded in the wall. It is aimed to reduce the total volume allocated for the ventilation device in the classroom compared to the use of a single device. To slow down fresh air entering the room at high speed and mix it before reaching breathing zone, blowing directions of the neighboring devices are intersected. With these information, a classroom model was created to be analyzed with the Computational Fluid Dynamics method. In addition, another classroom model was created for investigating personal ventilation scenario. By a comparative analysis, average air velocities, age of air values around heads of students and students' perception of indoor air quality according to Fanger's "Predicted Average Vote" method were investigated.Master Thesis Modelling and Controlling of Hybrid Energy Systems With Hydrogen Storage(01. Izmir Institute of Technology, 2023) Denizli, Osmancan; Çağlar, Başar; Altın, MüfitHybrid renewable energy systems are gaining more attention for the problems like Global Warming and high CO2 emissions. Another topic that increases its popularity is hydrogen. Because it is a very good alternative fuel. In this work, every component of a basic Hybrid Renewable Energy System (HRES) will be modeled and short-time simulations will be made for any transient response of individual components. MATLAB Simulink is used for every model and simulation. HRES includes a wind turbine, PV array, battery energy storage, and electrolyzer. The system is also grid-connected. Additionally, different control strategies are investigated, obtained, and created. Maximum Power Point Tracking (MPPT) algorithms for Wind Energy Conversion System (WECS) and PV array were conducted. A control algorithm that combines the battery and the PV array was made and necessary circuits were designed. An overall model for different sizes and operations is created. One-day-long simulations were made for 11 different cases. The user can alter the overall model for different turbines, PV modules, and battery sizes. The total amount of hydrogen produced, energy generation, and consumption were observed for every case.Master Thesis Modeling and Thermo-Economic Analysis of a Photovoltaic-Battery Hybrid Energy System: a Case Study in Yenikale Geothermal Heat Center(01. Izmir Institute of Technology, 2023) Uslu, Gökçe; Gökçen Akkurt, Gülden; Helvacı, Hüseyin UtkuWater is vital for agriculture accounting 50-70% of the total global use of fresh water for irrigation. Geothermal water as a renewable energy source is used to generate electricity, heat and cool. The remaining water can be desalinated to be used for agricultural irrigation. Energy demand of desalination systems is high and mostly rely on fossil fuels increasing cost and greenhouse gas emissions. Thus, renewable energy use in desalination process is increasing. Based on a research project, a pilot desalination system is installed in Yenikale Heat Center of Balcova-Narlidere Geothermal District Heating System to desalinate geothermal water and use for agricultural irrigation. The desalination system is powered by a solar PV system which meets energy need entirely in summer but only 30-50% in winter. The remaining energy need is supplied from the grid. The aim of this study is to maximize the utilization of solar energy for the desalination process while minimizing reliance on the grid. To achieve this objective, three different scenarios are analyzed based on three different solar radiation values of 2021 integrating a battery system. For each scenario; first, battery capacities and the number of PV panels are determined. Then, energy, exergy and exergo-economic analysis are conducted. The parameters calculated in economic analysis are net present value, payback period and cost of energy production. One of the main results obtained is the unit energy cost for solar driven desalination system 0.28 $/kWh which is in a good agreement with the literature (0.214-0.23 $/kWh).Master Thesis Techno-Economic Optimization of Pv-Wind Hybrid Systems(01. Izmir Institute of Technology, 2023) Demirdal, İlke; Çağlar, BaşarIn this study, the technoeconomic optimization of hybrid renewable energy systems were investigated for a small community with 50 households located in Izmir Institute of Technology (IZTECH) Campus, Izmir. The renewable-based power systems have received significant attentions recently due to the recent effort for the transition from fossil fuels to renewable energy, but their technical and economical feasibilities for different sectors and application areas and the related optimum system configurations haven’t been clearly addressed. To fill this research gap, PV-battery and wind turbine-battery system were analyzed for a small community from technical and economic point of views and the most economic configurations were explored for different level of grid-dependency by using the Loss of Power Supply Probability (LPSP) method. The annual electricity load profile was built in hourly basis based on the monthly total electricity consumption of each house and electricity consumption habits of residents. PV and wind turbine power outputs, the involvement of batteries were modelled in MATLAB/Simulink considering the meteorological data (IZTECH Meteorological Mast and NASA POWER), types of PV panel, wind turbine and battery. The mismatch between energy demand and supply was determined and different hybrid configurations were considered to cover this mismatch to different extents. The optimum number of PV panel, wind turbine and batteries were determined and the levelized cost of electricity were calculated for each scenario. The most economic configuration is the one consisting of 3 wind turbines and 7 batteries with 49.62% energy utilization from the grid.Master Thesis Energy Interaction of Vertical Axis Wind Turbines Working in Pairs(01. Izmir Institute of Technology, 2023) Gencer, Özgür; Karadeniz, Ziya HatanThe position of wind turbines relative to each other is important in terms of the performance of the turbines. The experiments and CFD studies in the literature have shown that Vertical Axis Wind Turbines (VAWT's) have a higher energy production per unit of land used than Horizontal Axis Wind Turbines (HAWT's) and it is found that there is a performance improvement of the VAWT's when they are operated in pairs. In this thesis, CFD simulations of the H-type VAWT's working in pairs have been perpormed to investigate the energy interaction of the turbines. A standalone one-bladed VAWT was modelled based on the previous studies in the literature for the validation of the CFD methodology. Simulation parameters and simulation settings are compared with the reference study in the mesh independency analysis for four different mesh settings resulting in a deviation of up to %14, and in the time step sensitivity analysis for two different time steps corresponding to 0.25 and 0.5 degrees of azimuthal angle increments resulting in a deviation of up to %15. 1, 2, and 3 bladed stand-alone turbines are investigated to reveal the effect of the inter-turbine blade interaction on the energy output. A pair of co-rotating turbines configuration is analyzed at various Tip Speed Ratios (TSR) (1.7, 2.2, 3.3, 4.4) and at compared with the standalone VAWT for each configuration. The results of CFD simulations show that adding blades to the standalone VAWT results in a more stable moment coefficient, but it also leads to a decrease in the power coefficient at high TSRs. The co-located turbines cause flow disruption for the VAWTs working in pairs operating at unstable TSRs (<2), resulting in a performance reduction of up 13.5%. Increasing the distance between turbines minimize the negative effect of disruption and improves turbine performance. As the TSR increases to a stable operation, the existence of the second turbine affects the energy output of both turbines positively, with the highest performance increase of 46% observed at TSR 3.3 when the turbines were placed closest to each other at 3D. The positive effect of the neighbouring turbine decreases as the distance between the turbines increase and the impact of distance between turbines on performance vanishes for the dewnstream turbine at 8D.Master Thesis Thermo-Catalytic Pyrolysis of Unrecycled Plastic Waste in a Lab-Scale Experimental Set-Up: Determination of Optimal Operating Conditions(01. Izmir Institute of Technology, 2022) Ekici, Ecrin; Yıldız, Günay; Çağlar, Başar370 million tons of polymers are produced worldwide annually (with an annual growth of 4%), of which ca. 16% are produced in the European Union (EU). By 2030, it is estimated that over 600 million tons of plastics will be produced. Plastic waste is a problem and will be severe day by day for the environment. This problem can easily switch to advantage by a carbon-neutral process: pyrolysis. This study analyzed and compared reported literature data with the experimental findings obtained in a continuously operated bench-scale pyrolysis reactor. The optimal conditions of the feedstocks' N2 flow rate, feed intake, and mixing ratio for maximizing liquid production were estimated for pyrolysis by Taguchi’s orthogonal array design. Optimized process parameters were used for the pyrolysis of fresh and waste counterparts of HDPE, LDPE, PP, and a defined mixture of those (25:25:50 wt.%) at 450°C. The tail gases of mixed fresh and waste POs were also examined for energy autonomy of pyrolysis. Fresh plastics yielded more liquid compared to waste plastics. Blending polyethylenes with PP improved the conversion efficiency and favored the formation of gasoline-range hydrocarbons while limiting the wax formation. The total energy potential of produced NCGs, mainly composed of C3 hydrocarbons, was found to be sufficient; the energy demand for endothermic bond breaking during pyrolysis was met in a range of 139 to 464% for various plastic types tested.Master Thesis Hybrid Renewable Energy Systems Design for Green Campus-Iztech(01. Izmir Institute of Technology, 2022) Ramazan, Beste; Çağlar, Başar; Açıkkalp, EminThis study focuses on evaluating of standalone PV and Wind systems integrated with energy storage technologies to meet the electricity needs of the Izmir Institute of Technology campus in Izmir. University campuses with their high energy demand are one of the most important application areas for renewable energy systems and it’s critical to determine the types of renewable energy technologies, their size, and techno-economic feasibility for possible future implementation. Solar and wind energy were chosen as renewable energy sources based on the location and renewable energy potential of the IZTECH Campus. Two different energy storage systems are proposed to prevent any loss of power supply in standalone mode: (i) Lead-acid battery and (ii) Electrolyzer, hydrogen storage tank, and hydrogen-powered generator. Models were developed using the dynamic library-based structure of the TRNSYS program. The hourly electrical load was generated based on monthly data taken from the electricity supplier and the power output of PV modules was calculated based on the fixed tilt angle based on real meteorological data for the campus location. The electricity demand and generation were analyzed hourly for one calendar year. The number of PV modules was determined to meet the annual electricity demand of the campus while the capacity and number of energy storage modules were determined based on the maximum accumulative energy deficiency in a year. The round-trip efficiencies and the depth of discharge for the battery and the hydrogen storage efficiency for the hydrogen-based storage option were considered in the analysis. Parameters were calculated for both systems and simulation analyzes were evaluated. An economic cost analysis was performed for each system. In addition, suggestions are made for possible system improvements.Master Thesis Wind Turbine Control Via Power Measurements in Complex Terrain(01. Izmir Institute of Technology, 2022) Dirik, Deniz Gökhan; Bingöl, FerhatThis work presents an approach to the assessment of wind farm yaw control to utilize wake steering in complex terrain based on power measurements. Aerodynamic interactions between closely spaced wind turbines reduce the power output significantly. The standard wind turbine control strategy currently focuses on optimizing the wind turbines individually. However, there is growing evidence that these wake losses can be improved by optimizing for aerodynamic interactions between the turbines. In a case study, an assessment of wake steering gain and optimum yaw offset angles for each wind turbine are simulated for an operational wind farm. Wake losses are simulated for the wind farm and are validated using historical power measurements. Data analysis procedures for implementing operational wind farm data for the wake steering approach are described. Optimum yaw offset angles are calculated in simulations using operational data. A lookup table is generated for the optimum yaw angles required for each wind direction and speed bin. Using 5-year-long operational data, an average of 0.48% wake losses are calculated for the site. FLORIS simulations suggest 9.6% possible power improvement in wake losses using the optimum yaw offset angles. Using SCADA measurements for potential wake steering assessment allows rapid assessment and implementation without requiring expensive and year-long LIDAR or meteorological mast tower measurements.Master Thesis Short-Term Wind Speed and Power Forecasting: a Comprehensive Case Study for Three Operational Wind Farms(01. Izmir Institute of Technology, 2022) Yoldaş, İrem Selen; Bingöl, FerhatWind energy is gradually growing with the increasing energy demand. However, the rising wind power penetration into modern grids could seriously affect the safe operation of power systems and power quality due to the intermittence and randomness of wind characteristics. Several effective ways could be considered to mitigate these issues: a robust power grid, energy storage, and wind power forecasting. Optimal integration of wind energy into power systems calls for high-quality wind power predictions. This research focuses on the short-term forecast of wind speed and power generation. Firstly, wind speed forecasting is studied. A case study is performed to analyze the forecasting performance of five approaches: the multivariate Facebook Prophet, seasonal autoregressive integrated with moving average (SARIMA), SARIMA with exogenous variable (SARIMAX), gated recurrent units (GRU) and long short-term memory (LSTM). The performance indicators are applied to verify the effectiveness of models, which are R-square (R2), mean square error (MSE), root mean square error (RMSE), and mean absolute error (MAE). The predictions obtained by the LSTM model almost coincide with the real-time wind speed, which is also supported by the performance indicators, which indicate that the LSTM model outperforms the other methods for the real-time dataset of IZTECH meteorological mast. The second part of the study is to forecast the wind power generation using the LSTM model and the wind speed forecasts and wind speed power curve of wind turbines in the wind farms. The proposed model is validated using the real-time wind power generation data from the EPIAS Transparency Platform. Due to the unavailable meteorological dataset, an ERA5 dataset of the location is used to predict wind speed and power generation. Also, each wind farm's daily forecasts are obtained to investigate the results for Day-ahead Market. The results indicate that using the LSTM model with the ERA5 dataset could give better forecasts than wind farms’ own forecasts. Additionally, it is understood that if the SCADA data could be obtained, the forecasting performance might be increased.