Mugdesem Tanrioven

Financial payback analysis of small wind turbines for a smart home application in Istanbul/Turkey

Small-scale wind turbines are promising renewable energy devices driven by the aim of carbon savings at energy generation. However, the use of small-scale wind turbines in residential areas is still very narrow because of low wind speeds, high turbulence intensity, and the perception of high aerodynamic noise produced by wind turbines. Furthermore, their high cost make it essential to assess the turbines carefully before deciding to purchase so that the optimum performance and costs can be obtained. In this study, power curves of bestselling small scale wind turbines in Turkey are compared using experimentally collected one year wind data for the use in a smart home environment at Davutpasa Campus, Istanbul. The total annual energy production of the wind turbines and financial payback periods are calculated. With the results of performed analysis, it is possible to define the most profitable small wind turbine to be used in related applications in Istanbul and in areas where wind speed is similar.

A New MPPT Algorithm for Vehicle Integrated Solar Energy System

Photovoltaic (PV) systems are considered as a support unit and eco-friendly energy source for the electric vehicles. If the surface of the electric vehicle is covered by PV cells, it is possible to store considerable amount of energy in the battery system. In this study, different maximum power point trackers (MPPT) with different maximum power point (MPP) tracking algorithms have been tested on a PV structure moving according to a predefined motion loop. Compatibility of each algorithm to moving systems, such as electric vehicles, is presented in a real experimental environment. As a result of these experiments, positive factors in each algorithm have been defined and a new MPP tracking algorithm convenient for moving vehicle has been proposed. The proposed MPPT algorithm shows a better performance than other MPPT algorithms under fast varying radiations. However, proposed algorithm brings slightly higher costs compared to usage of other MPPT algorithms since it requires the measurement of solar irradiance. The developed algorithm is described in detail and comparative analysis and performance evaluation with other algorithms are presented. Autor Nakir, Ismail; Durusu, Ali; Akca, Hakan; Ajder, Ali; Ayaz, Ramazan; Ugur, Enes; Tanrioven, Mugdesem Quelle Transactions of the ASME, Journal of Energy Resources Technology * Band 138 (2016) Heft 2, Seite 021601/1-9 (9 Seiten)

Photovoltaic System: Case Studies

Solar energy is one of the most important energy, which is environmentally friendly such as clean, inexhaustible and free, among the renewable energy sources. Studies on solar photovoltaic (PV) energy generation system were promoted in last two decades. The main application of PV systems are in stand-alone (water pumping, lighting, electrical vehicle, etc.), hybrid and grid-connected (PV power plants) configuration. Stand-alone PV power generation system is considered as good alternative for places that are far from conventional power generation/transmission/distribution system. PV generation systems have two big problems; PV conversion efficiency is very low and PV electricity generation is effected from changing of weather condition. PV output varies periodically in a year and in a day, and is not stable due to environmental condition. Accordingly, in order to increase PV output and PV efficiency, it is crucial to analyze PV output considering solar radiation, temperature, wind speed, shadow, etc. Maximum power point trackers (MPPTs) are employed for extracting power from photovoltaic (PV) panels. MPPTs enforce the solar modules to operate at maximum power point (MPP) under the fluctuations of ambient conditions. Therefore, they take a vital role for increasing of PV system efficiency. In this part, the case studies of MPPT system, which includes stand-alone and hybrid PV systems, will be briefly reviewed, followed by discussion of the MPPT modeling, design, etc. Several stand-alone and hybrid MPPT application will be presented. Latest developments in MPPT methods will be summarized. Finally some of the present challenges facing the MPPT techniques will be explored.

Thermal management of power LED system

LEDs are used in many areas today. Street lighting is one of them and high-power LEDs are utilized in this area. Electrical energy is converted into light with an efficiency in 10-25% range. The rest is converted into heat. The generated heat is largely caused from LED chip. Furthermore, Driver circuit would also causes heat rise. Removing of this heat from the system is important in order to LED system efficiency because increasing of temperature causes a reduction of luminous flux. Excellent thermal management plays a significant role in terms of efficiency, reliability and durability. In this study, losses are caused from the LED chip and the heat sink which are part of the LED lighting systems are examined. These elements are thermally analyzed. The impacts of these losses on efficiency will be presented.

A new approach for relationship between daylight and indoor illumination level

In recent years, the studies on energy efficiency in both industry and academia increased visibly worldwide. As the result of these studies, DIN V 18599-4 is published in 2007. According to this pre-standard, calculation methods about building energy performance were prepared. During design process of building for high energy efficiency, pre-standard contains daylight supply factor. However these calculations are so complex for software development. Our studies on these calculations indicate that there are a lot of parameters which affect the results so realistic results cannot be obtained easily. Also, indoor lighting energy is affected from these results. These are disadvantages of this method. This study provides an alternative for calculation methods of daylight supply factor which is given in DIN V 18599-4 pre-standard. The relationship between global radiation on horizontal surface and building zone that has window is established and it is formulized empirically. Therefore, by using this formula the effect of daylight in windowed zone can be calculated. The number of calculations of this presented method is quite simpler and these calculations provide more realistic results than the pre-standard method in terms of indoor lighting energy.

Continuous Control of a Synchronous Generator's Active and Reactive Power Connected to Network by Using Fuzzy Neural Networks Algorithms

The fuzzy logic controller based on the fuzzy set theory provides a useful tool for converting the linguistic control rules from the expert knowledge into automatic control rules [1]. By using fuzzy automatic rules from the heuristic or mathematical strategies, complex processes can be controlled effectively in many situations. But the most important and difficult point is how to obtain the proper control rules for a given system. In addition to that Artificial Neural Networks (ANN) is successfully used in many areas such as fault detection, control and signal processing in our daily technology. Artificial Neural Networks have nonlinear structure and this is an effective feature that it approaches to the results of learning phase. Then, it gives results in test phase in short time (the degree about 10−3 second). It is a very preferable according to the other approaching methods.