Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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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 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 Hydrodynamic Investigation of an Innovative Floating Platform for Offshore Wind Turbines(01. Izmir Institute of Technology, 2022) Girgin, Elif; Özbahçeci, BergüzarWith the realization of the potential of wind energy in deep water, interest in floating platforms is increasing. In this study, the hydrodynamic behavior of offshore floating wind turbines was examined experimentally and numerically. This study is the first small-scale experimental model study on floating offshore wind turbines in Turkey. Experiments were carried out in the wave channel with dimensions of 40.0m×1.0m×1.4m in the hydraulic laboratory of the IZTECH Civil Engineering Department. A new floating platform developed through a Tübitak project was tested under various wave and extreme wind conditions. Responses of the turbine and platform system and the tensions in the mooring chains were measured. Free decay, hydrostatic, quasi-static, and regular and irregular wave and wind tests were performed. Results were compared with the results of the existing spar platform model tests under the same test conditions. It was concluded that the innovative platform was more stable than the spar platform, especially in terms of rotation in the y direction, which is critical for stable energy generation and fatigue loads. The new platform, together with the turbine and the mooring lines, was also modeled numerically using a potential theory-based program. Experimental free decay tests were used to calibrate the numerical model. After calibration, regular and irregular wave test results were used for the validation. Agreement between the numerical and experimental model studies showed that the numerical model of the innovative floating platform was verified and could be used to develop and examine the platform on a prototype scale.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.Master Thesis Model Design and Experimental Investigation of Floating Wind Turbine(01. Izmir Institute of Technology, 2022) Arıdıcı, Ali; Özkol, ÜnverFloating offshore wind energy has great potential (which constitutes almost 80% of total offshore wind energy) to meet electricity demand of the world at the same time to reach net-zero emission goal by 2050. Floating offshore wind turbines (FOWT) are able to achieve highest capacity factor since local effects of the offshore terrains are lesser. Thus, it receives stronger and more stable wind. On the other hand, combined hydrodynamic and aerodynamic forces with 6 degrees of freedom (DoF) bring unsteadiness and there- fore, challenges on FOWT design. Furthermore, significant rotational motions, particu- larly pitch motion, lead the turbine to transient state which can not be simulated through conventional numerical tools. Therefore, to understand the dynamics of the FOWT, it is necessary to conduct experimental studies to obtain results by considering all the param- eters. The main aim of the thesis is to investigate the dynamic response of the FOWT under the extreme wind and wave conditions. A 1/40 Froude-scaled version of the Northel POYRA P36/300 mounted on the spar-type floating platform was developed by colleagues as a part of TUBITAK (217M451) project. In this thesis, experimental studies were car- ried out in the wave flume with a wind nozzle in the hydraulic laboratory of IZTECH Civil Engineering Department. Atmospheric boundary layer (ABL) was scaled, and in- struments of the experiment were calibrated to characterize wind nozzle and wave maker, which are vital to obtaining reliable results. The wind nozzle was designed based on experimental data to reproduce correct Froude-scaled ABL.Master Thesis Wind Turbine Power Curve Update Based on Atmospheric Conditions and Structural Fatigue(Izmir Institute of Technology, 2020) Demir, Erdem; Bingöl, Ferhat; Gökçen Akkurt, GüldenWind energy is still developing industry and people who work in this industry working hard to accomplish the difficulties. Problems are not arise only by nature of wind but technological developments, methods and even market pressure itself. Wind turbine theoretical power curves are given only for certain conditions and one can easily say that those conditions are not met in real sites. This difference generates a uncertainty in AEP calculations thus financial models become less reliable. Shifting power curve by taking atmospheric effects into account will give more realistic power curve thus more accurate AEP and financial models. In this study, effects of atmospheric conditions and correction methods on NREL 5MW wind turbines power curve have been investigated and importance of corrected power curve has been discussed.Master Thesis Frequency Control in an Isolated Power System With High Penetration of Wind Power(Izmir Institute of Technology, 2019) Hassan, Ali; Bingöl, Ferhat; Altın, MüfitAs the percentage of wind energy in global energy portfolio rises, the wind turbine control is becoming increasingly important for the integration of wind turbines in power systems. The early control objective of wind turbine control was only to maximize the power output but now the wind turbines are required to provide frequency control as well. To emulate the inertia response (IR) of the conventional synchronous machines the wind turbines can be provided with an inertia emulation controller. The modelling work presented in this thesis aims at equipping the modern Type D wind turbine with inertia response and primary frequency control capabilities. Two controllers — inertial and droop, are implemented and their frequency control capabilities are compared in an isolated power system consisting of a conventional steam turbine generator and a wind farm. A model of one Type D wind turbine is simulated and aggregated for the whole wind farm. The ability of wind turbines to provide inertial response (IR) and primary frequency control (PFC) after a frequency deviation shows a better performance than the case when there is no contribution to frequency control through wind turbines.Master Thesis Steady and Unsteady Aerodynamic Analysis of the Airfoil Profiles by Using Vortex Singularity Elements(Izmir Institute of Technology, 2018) Elmacı, Salim Cenk; Özkol, Ünver; Özbahçeci, BergüzarThe steady and unsteady 2D flows around the airfoil were analyzed by utilizing the vortex singularity elements with two different inviscid flow models. Firstly, the steady flow was modeled in the light of steady state algorithm available in the literature. Then, the unsteady flow model was developed by some modifications on the algorithm of the steady flow. All the algorithms were transformed to the code in MATLAB® 2018a environment. For the steady state model, lift coefficients were compared with the inviscid and inviscid-viscous coupling models of the Xfoil 6.9 program data (Drela, 2001); and NASA experimental archive (Ira Herbert Abbott & Von Doenhoff, 1959). Since the model is inviscid, the reference point is the inviscid solvers; and the model agreed well with the Xfoil 6.9 inviscid mode for different type of airfoils. The unsteady model was created with three different operating modes; which are the sudden forward, heaving and the pitching. For the sudden forward motion, the lift and drag coefficients were compared with the studies in the literature. Besides, the lift, drag moment coefficients; and the wake patterns of the heaving and pitching motions were compared with the experimental data in the literature. The model is limited in terms of reflecting lift, drag and moment coefficients due to the not being included the viscous effects, flow separation, stall etc.; however, in terms of capturing the wake patterns, the model is quite useful.Master Thesis Hybrid Energy Capacity of Turkey for Small and Micro Scale Energy Production(Izmir Institute of Technology, 2017) Yıldız, Mustafa; Bingöl, Ferhat; Gökçen Akkurt, GüldenTurkish state has opened a new possibility on investing small or micro scale energy production without license in 2014. This is a new step in Turkish energy market and two renewable energy sources are considered to be the main interest; wind and solar. Although there are studies covering both technology separately, currently there is no hybrid system assessment methodology and results for the country. This thesis aims to create a quantified hybrid energy capacity of Turkey. The study will include total energy capacity of a given location based on small scale wind and solar and furthermore would be able to suggest an optimum balance between these two sources to get the maximum production capacity out. The study does not cover areas that such investment cannot be done; environmental protected areas, historical places, city centers etc.