Yazar "Tutkun, Nedim" seçeneğine göre listele
Listeleniyor 1 - 20 / 27
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Basic Parameter Extraction From An Organic Solar Cell Through The Single Diode Model And A Metaheuristic Technique With The Lambert W Function(Ieee, 2014) Tutkun, Nedim; Elibol, Erdem; Maden, DinçerRecently solar power has increasingly been used to generate electricity worldwide through photovoltaic (PV) systems. The electrical performance of each PV module plays major role in maximum power transfer. In order to absorb the maximum power from such systems, optimal output voltage and current should be obtained from the I-V characteristics of previously developed models. It is fact that, this is a relatively uneasy task because manufacturer's data sheet is confined to limited number of measured values. In this study, the hybrid genetic algorithms method is employed to extract basic parameters of the ideality factor and the parasitic resistances in the single diode model to transfer maximum power from a PV module to a resistive electrical load. Optimal parameters in the circuital model are found using the I-V characteristic of a silicon diode expressed by the Lambert W function. The results are meaningful and encouraging for maximum power transfer under certain conditions.Öğe Comparison of ABC and Genetic Algorithms on Economic Power Dispatch(Ieee, 2018) Afandi, A.N.; Fadlika, Irham; Sendari, Siti; Miyauchi, Hajime; Fujita, Goro; Tutkun, NedimRecently, an economic evaluation of the power system becomes one of main issues in the power system management since the power production and power selling consider a financial aspect. The system should be operated in the lowest cost and cheaper fee for consumers. In particular, an environmental protection also becomes a major issue to penetrate the pollutant production of thermal power plants. To cover this issue, one of strategies is approached using a combined economic emission dispatch (CEED) considered an economic dispatch (ED) and an emission dispatch (EmD). In these studies, the CEED is optimized using Artificial Bee Colony Algorithm which is contrasted to Genetic Algorithm for comparing both performances. By considering both algorithms, results show that generated powers lead to the total cost and pollutant emission. The total minimum cost is performed in the optimal solution with different speeds. Combinations of ED and EmD also give difference implications.Öğe Comparison of Typical PV Module Performances Based on the Circuit Models(Ieee, 2018) Tutkun, Nedim; Gegin, Keziban; Sarma, Nur; Salam, Z.In PV systems, it is usually expected that power generation under varying conditions at any time should be maximum as much as possible. Therefore, it is essential to build a circuit model based on a widely used single or double diode model under instantly varying conditions with minimum estimation error through the measured values in the manufacturers' data sheet. It is fact that these approximate circuits models ease the performance analysis of PV systems if the unknown parameters are accurately estimated at various temperatures and unchanged irradiance levels or vice versa. This paper comparatively studies the performances of the two approximate circuit models for the four types of PV modules using the real-coded genetic algorithms. The results indicated that I-V characteristics obtained from the identified parameters exhibit almost similar trend with those given in manufacturers' data sheets under the same conditions. Besides, the estimated parameters obtained from using both models slightly show difference from each other and it can be said that the single diode model is solely satisfactory to model a typical PV model as long as they are accurately estimated.Öğe Daily Cost Minimization for an Off-Grid Renewable Microhybrid System Installed to a Residential Home(Ieee, 2015) Tutkun, Nedim; Can, Özay; Şan, Ender SinanElectricity prices inevitably increase in many countries due to various reasons such as growing demand, incremental costs etc. This obviously has considerable impact on electricity consumers using electrical household appliances in daily life. In Turkey, rise of electricity price is almost around 10% every year and unfortunately this leads to budge from living comfort. Use of renewable energy systems is one alternative to reduce energy cost in family budget. The recent survey has shown that Turkey is rich in renewable energy sources in order to generate low cost electricity in residential homes or similar places using a typical micro-hybrid system with very low power wind turbines, several PV panels, few storage batteries and controllable and uncontrollable electrical loads. The operational cost of this system should be reduced to competitive amount of the grid cost. This is actually a typical global minimization problem with several constraints to be solved. In this investigation, the problem was solved by the SFLA technique and the results indicated that operational cost in a PV/wind micro-hybrid renewable system is considerably reduced.Öğe Determination of capacitance range in the self-excited induction generator through the hybrid genetic algorithms(2010) Tutkun, Nedim; Arslan F.The self-excited induction generators (SEIGs) are mainly demanded for generation of electricity in remote areas due to several advantages such as less maintenance, rugged construction etc. The SEIG's excitation is usually supplied from a capacitor bank whose capacitance plays major role in transferring power into the load. Previous investigation has shown that excitation is only possible between minimum and maximum capacitances and the resonant capacitance lies down in this range. Determination of these capacitances involves in a numerical solution of transcendental equations extracted from the steady state equivalent circuit of the SEIG. Although the Newton-Raphson method is extensively used to solve these equations however it is inefficient in most cases. In this paper, the hybrid genetic algorithms (HGA) technique is proposed to solve these equations to obtain necessary capacitance range for excitation under ohmic, inductive and capacitive load conditions. The proposed approach produces meaningful and encouraging outcomes for understanding the SEIG's performance from various aspects. © 2010 IEEE.Öğe Forecasting of daily natural gas consumption on regional basis in Turkey using various computational methods(Elsevier Science Sa, 2013) Taşpınar, Fatih; Celebi, Numan; Tutkun, NedimIt is widely accepted that natural gas is a clean energy source that can be used to meet energy demand for heating and industrial purpose among the fossil fuels and its usage remarkably increases in order to maintain a clean environment in many countries in the world. It is fact that this makes energy investment planning in a country or region highly important for suitable economic development as well as environmental aspect. Therefore, energy demand for various sectors should be estimated in the frame of short-term energy policy. For accurate estimation of short-term energy demand a limited number of computational methods are employed by using the 4 yearly measured natural gas consumption values. Among these methods, the ANN and time series are widely used for short-term estimation of natural gas consumption in Turkey's certain regions. In this study, multilayer perceptron the ANNs with time series approach is proposed to forecast short-term natural gas consumption. Meteorological data (moisture, atmospheric pressure, wind speed and ambient temperature) obtained from the regional gas distribution company and the local meteorology office in last 4 years to construct well-tuned algorithm. Although the number of data was small, the proposed algorithm works well to forecast the short-term natural gas consumption and produces encouraging and meaningful outcomes for future energy investment policy. (C) 2012 Elsevier B.V. All rights reserved.Öğe Harmonic elimination in a single phase inverter output voltage with 2 and 4 bipolar notches in a half cycle by the HGA(2010) Tutkun, Nedim; Türkkan, Y.; İbrahimbaş, M.; Yücel, N.Inverters are power devices used for many industrial applications such as power conversion, the speed control of induction motors etc. When a magnetic device is energized by an inverter power supply, its magnetic core is subjected to additional core losses due to harmonic contents. One solution to this problem may be the selective harmonic elimination based on the simultaneous solution of non-linear equations that are mainly function of the switching angles. In this paper, the hybrid genetic algorithms method was used to eliminate the dominant harmonics leading to additional losses in a strip wound toroidal core used to build a low power transformer. The results indicated that the proposed method works well and it achieves to reduce the total harmonic distortion at the primary current and the induced voltage of the transformer under both ohmic and inductive loads. © 2010 IEEE.Öğe Improved Approach To Extract Maximum Power From A Small-Scale Fixed PV System(Ieee, 2016) Tutkun, Nedim; Aktaş, MelihIt is obvious that irradiation level and cell temperature are mainly influential on I-V characteristic of a PV module. A change in optimal operation point of voltage affects maximum electricity generation transferred to a load. Therefore, it is necessary to use a dc-dc converter to adjust PV output voltage to optimal point of it under constant load conditions. To do that I-V curve of the PV module should first be obtained at given insolation rate and temperature and the dc-dc converter is used to set the voltage to optimal point. In this study, at certain ranges of irradiation level and temperature the I-V curve was obtained through parameter extraction from the single diode model using the genetic algorithm. The duty ratio of the dc-dc converter is optimized until the input resistance of the converter equals the optimal resistance under varying irradiation level and temperature. The results are meaningful and encouraging compared to those of similar works.Öğe An Improved Approach to Minimise Energy Cost in a Small Wind-Photovoltaic Hybrid System(Ieee, 2016) Tutkun, Nedim; Celebi, NumanToday recent developments in renewable technology such as wind and photovoltaic systems encourage people to generate electricity with low investment costs. In this manner, this may result in partial reduction in power demand hence import of primary sources may gradually decline as well as foreign dependence on energy. Furthermore this lets decrease power losses in transmission lines by reducing power generation capacity in power stations. The widely use of wind turbines and photovoltaic systems in residential and official buildings depends on being economic investment and operation costs. The unit investment cost shows no big difference in all the renewable systems but, to make operation cost lower the balance between production and consumption at any time interval must be maintained without shedding loads. For instance, in case of an hour time interval this balance should be maintained for 24 times in a day however this may not always be possible since sources of renewable energy are irregular. At some time intervals, a power boost is needed either by adding a power source to renewable system or by shedding loads according to their priorities but this is not desired case. In this study, the problem with 7 constraints was solved by a combinatorial optimization based the real-coded genetic algorithms to reduce operation cost to acceptable level and balance between generation and consumption at all the time intervals. The results are encouraging and meaningful for similar applications.Öğe Improved load shifting and valley filling strategies in demand side management in a nano scale off-grid wind-PV system in remote areas(Ieee, 2017) Tutkun, Nedim; Üngören, Furkan; Alpağut, BişarIt is reported that residential buildings almost consumed around 30% of electricity generated among other sectors such as industry, commercial and public services etc. In developing countries considerable amount of people have no direct access to the national power grid or are encountered long power blackout. Therefore people in those countries are very limited to use of electricity for routine basic daily applications in their homes. In this study, power demand for those who live in such countries are met by a nano scale autonomous wind-PV system through the demand side management in order to reduce total daily energy cost to reasonable price as much as possible. The preliminary results indicated daily energy cost can be achieved to have competitive prices depending on renewable energy potential and sustainable energy production for 20-25 years of lifetime is also possible for emergency cases.Öğe Improved photoluminescence and monodisperse performance of colloidal CdTe quantum dots with Cannula method(Korean Institute Chemical Engineers, 2019) Elibol, Erdem; Elibol, Pınar Sevim; Çadırcı, Musa; Tutkun, NedimColloidal quantum dots are nano semiconductor materials that have been found in many applications, producing multiple exciton generation, unique optical and electronic properties, adjustable in size and bandwidth. Synthesized QDs are expected to exhibit high photoluminescence quantum yield and monodisperse properties according to their application area. Cannula method was adapted together with the organometallic synthesis method for the first time in the literature to increase the photoluminescence quantum yield of organometallic CdTe QD and minimize the full width at half maximum value of the photoluminescence band. Injection of precursors by the Cannula method is much faster than the injecting with the conventional method of using a glass syringe, which limits the size distribution in the solution during synthesis. In addition, the fastest injection method using Cannula method yields the shortest full width half maximum value of 27.20 nm for CdTe QDs in the literature. The photoluminescence quantum yield value of the CdTe QDs synthesized by the classical method was 8.12 +/- 2.1%, while the photoluminescence quantum yield of the CdTe QDs synthesized by the Cannula method was increased to 25.66 +/- 2.1%.Öğe Improving CdTe QDSSC's performance by Cannula synthesis method of CdTe QD(Elsevier Sci Ltd, 2019) Elibol, Erdem; Tutkun, NedimIn this study, CdTe Quantum Dots (QDs) used in QD Sensitized Solar Cell (QDSSC) design were synthesized by Cannula method. Cannula method is a method used to minimize problems occurring in hot injection method, while reducing the Full Width Half Maximum (FWHM) value to 27.20 nm, QD's Photoluminescence Quantum Yield (PLQY) increased to 25.66 +/- 2.1%. This study was carried out to determine the effects of CdTe QDs synthesized by Cannula method on CdTe QDSSC application. Firstly, CdTe QDSSCs with the same parameter values (TiO2 thickness, redox couple, collecting electrode, coating technique and duration) were designed with CdTe QDs synthesized by using classical method and Cannula method. The Photo Conversion Efficiency (PCE) of QDSSCs using CdTe QDs synthesized by Cannula method was 0.234%, 2.68 times bigger than the PCE of the CdTe QDSSC synthesized by the classical method. Then, to determine how the size of CdTe QD affects the PCE of CdTe QDSSCs, 6 CdTe QDSSCs were designed by using different size CdTe QDs which were synthesized by Cannula method. In addition, the FTO/TiO2 surface was treated with TiCl4 in CdTe QDSSCs designed. The decrease in the size of the CdTe QD has been found to increase the PCE of CdTe QDSSC. As a result, the PCE of CdTe QDSSC was increased to 0.385% by using 2.80 nm CdTe QDs synthesized by Cannula method. This PCE is the highest value in CdTe QDSSCs designed using CdTe QDs synthesized in the literature by hot injection method. The current density (J(sc)) and open circuit voltage (V-oc) of the designed CdTe QDSSC were found to be 1.292 mA/cm(2) and 0.724 V, respectively.Öğe Improving the performance of CdTe QDSSCs by chloride treatment and parameter optimization(Elsevier Sci Ltd, 2019) Elibol, Erdem; Elibol, Pınar Sevim; Çadırcı, Musa; Tutkun, NedimIn this study, organometallic CdTe(Cl) Quantum Dot Sensitized Solar Cells (QDSSCs) using cadmium chloride (CdCl2) treated CdTe QDs were designed for the first time in the literature. The study is divided into 3 basic sections; synthesis of CdTe QD, treatment of CdTe QD with CdCl2 and design CdTe(Cl) QDSSCs. The hot injection method modified by Cannula method was used to synthesize organometallic CdTe QDs. The chloride passivation procedure was applied to CdTe QD with injection of different amount of chloride (12-96 CdCl2/nm(2)) into the CdTe solution. Uv-vis, Photoluminescence (PL), PL Quantum Yield (PLQY), Full width Half Maximum (FWHM) analyses were performed for all CdTe QDs which were synthesized and treated with chloride. As a result of the analyses, PLQY value was increased from 25.66 +/- 2.1 to 87.33 +/- 2.1% with 60 CdCl2/nm(2) treatment. To determine the effects of chloride treatment on QDSSC, CdTe QDSSCs were designed using 6 different CdTe (CI) QDs obtained by different amounts of chloride treatments applied to the surfaces of CdTe QDs. After that, TiO2 thickness, collector electrode selection were chosen by experimental optimization. As a result of the study, FTO/TiCl4/TiO2 (22 mu m)/TiCl4/(36 CdCl2/nm(2)) CdTe(Cl) QD surface was used as the photo anode at the end of all optimization procedures, while FTO/Pt was selected as the collecting electrode surface. I-/I-3(-) redox pairs were injected between these two surfaces. For the designed QDSSC, J(sc), V-oc, filling factor (FF), Power Conversion Efficiency (PCE) were found 2.842 +/- 0.10 mA/cm(2), 0.810 +/- 0.019 V, 56.630 +/- 1.79%, 1.306 +/- 0.10% respectively. This efficiency value is 5.58 times better than the most efficient CdTe QDSSC's efficiency (0.234%) obtained by using organometallic CdTe QDs in the literature.Öğe Low cost operation of an off-grid wind-PV system electrifying residential homes through combinatorial optimization by the RCGA(Institute of Electrical and Electronics Engineers Inc., 2018) Tutkun, Nedim; Can, Özay; Afandi, A.N.A low power off-grid wind-photovoltaic system is increasingly used to energize residential homes in remote areas where no grid utility or grid extension is available. An economic design of such a system for 20-year lifetime requires optimal unit sizing as well as investment, operation and maintenance costs. However power generation by this system varies from one day to another due to irregular natures of wind speed and solar irradiation. Therefore battery storage is needed to integrate into this system if all the electrical appliances are desired to uninterruptedly feed and this requires to efficiently manage battery operation. Besides, load shifting can be applied to such a system through controllable loads in order to balance generation and consumption at each time interval as much as possible. One way to balance generation and consumption in a specified period is possible to solve a discrete optimization problem defined as minimization of daily cost with few constraints for optimal time slots. In this study, minimization of total cost for such system is achieved by the real-coded genetic algorithms technique from various aspects. The results obtained are meaningful and encouraging to design and operate such a low cost system. © 2017 IEEE.Öğe Minimization of operational cost for an off-grid renewable hybrid system to generate electricity in residential buildings through the SVM and the BCGA methods(Elsevier Science Sa, 2014) Tutkun, NedimRecently Turkey's electricity demand has shown a considerable increase due to its population and economic growths. It is understandable that this may be very influential on electricity price on market as well as other factors such as an increase in natural gas price, etc. It should be noted that the half of Turkey's electricity generation is supplied from natural gas and 95% of this source is imported from other countries. However, Turkey is rich in wind and solar energy potentials to generate electricity and it is believed that this makes a considerable impact on reducing high electricity unit cost to competitive one. In this regard, these potentials can be utilized for electricity generation in order to meet a significant portion of the power demanded by residential houses through a PV/wind system. The electricity cost of the renewable system can be minimized by optimally scheduling generated and consumed powers. In this paper, optimal power scheduling in such systems is carried out by using the BCGA and the SVM methods. The results indicated that the proposed approach was able to minimize the operation cost in the hybrid system through the optimal power scheduling. (c) 2014 Elsevier B.V. All rights reserved.Öğe Modeling of a Typical Photovoltaic Module using Matlab/Simulink(Ieee, 2018) Sarma, Nur; Gegin, Keziban; Şimşir, Mehmet; Tutkun, NedimThis paper presents detailed modeling principles of a typical photovoltaic (PV) module using the Matlab/Simulink software. The presented model is based on equations that are obtained from equivalent circuits of the single and double diode models. The presented models are designed with user-friendly blocks from the Simulink block library. The models provide better understanding of the output characteristics of a typical PV module and its changes, since the models can predict the behavior when it operates under various design parameters, as well as environmental conditions. The P-V and I-V output characteristics are determined using the developed models under various temperature and solar irradiation conditions. The accuracy of the developed models is validated by comparing the predicted results with the parameters provided in the datasheet of the investigated PV module.Öğe Optimal Design of a Rooftop Wind-PV Hybrid System to Meet Energy Demand for a Typical Residential Home in 20-Year Lifetime Projection(Ieee, 2018) Tutkun, Nedim; Bozok, Necati; Şimşir, Mehmet; Alkhesha, AussamaThe need for electrical power gradually increases every year due to population growth and economic development in particular in developing countries. The primary sources of electricity are usually fossil fuels such as coal, natural gas, oil etc. and major part of them is imported by those countries. This is unfortunately a typical indication of the energy dependence and play strategic role in economic development of the developing countries since some cannot switch to renewable energy use despite they have abundant renewable energy potential. The fact that the use of renewable energy is not widespread in those countries and it can be seen as not making enough investment by the government or private sector. This potential can be utilized by using on-grid/off-grid renewable systems in particular wind-PV systems ranging from power ratings of 1 to 10 kW in remote areas. To make such systems economic, power balance between generation and consumption should be maintained at hourly time slots in the day. One way to do that is to solve a discrete optimization problem and the solution can be achieved by a mathematical model satisfying the given constraints in a certain location. Unit sizing of a low power off-grid renewable system to meet power demand for a typical residential home in a location is achieved and the outcomes are meaningful and encouraging for widening renewable energy applications worldwide.Öğe Optimal load management in a low power off-grid wind-photovoltaic microhybrid system(Ieee, 2016) Tutkun, Nedim; Can, ÖzayThe most significant problem is to balance between generation and consumption in power systems ranging from small to large scales. This may be done by daily load scheduling in small-scale systems using metaheuristic optimization techniques such as the GA, the PSO and the SA etc. In the case of an off-grid low power wind-photovoltaic hybrid system, it is expected to power the loads without shedding and this may require scheduling loads on the basis of power balance, continuously energizing loads and low operation cost as much as possible at each interval of in a day. The fact is that it is a complex optimization problem with several constraints and this problem should be solved 24 times for an hour time interval. Due to incapability of deterministic techniques the GA or similar techniques may be the best approach to solve this problem for optimal power management. The construction of objective function is considered to reduce operation cost and use stored energy in the micropower system consisting of a 1 kW wind turbine, 8 photovoltaic panels, a diesel generator and 4 gel batteries. The problem under consideration is solved by the GA for an hour time interval during a day. The results indicated that the balance between generation and consumption can mostly be maintained and operation cost and energy efficiency are improved with respect to an unscheduled case.Öğe Optimal power scheduling of an off-grid renewable hybrid system used for heating and lighting in a typical residential house(Ieee, 2013) Tutkun, Nedim; Şan, Ender SinanIn Turkey, there is a significant increase in demand for electricity due to population and economic growth taken place in recent years. This is a major economic factor affecting electricity price on market as well as other factors such as an increase in oil and natural gas prices. To be more specific around 50% of electricity is generated by natural gas generators and 95% of natural gas is imported from other countries. However, Turkey has considerable amount of wind and solar energy potentials to generate electricity through wind turbines and photo-voltaic arrays either on-grid or off-grid. An off-grid hybrid system is more attractive in rural areas where access to grid is limited or unavailable. This study focuses on a power scheduling in a simple renewable hybrid system in order to minimize the operational unit cost using the binary-coded genetic algorithm instead of using mixed integer linear programming. The preliminary results indicated that the binary-coded genetic algorithm produced encouraging and meaningful outcomes to minimize operational unit cost in a typical renewable microgrid photo-voltaic/wind hybrid system.Öğe Optimum Unit Sizing of Wind-PV-Battery System Components in a Typical Residential Home(Ieee, 2016) Tutkun, Nedim; Celebi, Numan; Bozok, NecatiOptimal unit sizing of generation units in small offgrid systems is an important aspect to minimize total annual cost. This can be applied to wind, photovoltaic (PV), and hybrid wind-PV power generating systems to meet power demand for a residential home constructed at a specific site located in remote hilly areas in Turkey's northwest Black Sea coast where no grid extension is available. It is obvious that unit sizing of a standalone wind-PV system simply requires an optimization task to determine the optimal generation capacity and battery storage for a typical load profile. In optimization process, power demand, wind speed, and insolation rate are annually averaged hourly estimated values for the given site. The six combinations of PV alone, wind alone and hybrid wind-PV systems are optimally sized to both meet load demand and minimize total cost for 20-year lifetime projection using the real-coded genetic algorithms. The results indicated that a hybrid system with a 3 kW wind turbine and three 0.25 kW PV panel was the best configuration to reduce total annual cost to an affordable price for the specific example.
