Energy Systems Engineering / Enerji Sistemleri Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4752
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Article Citation - WoS: 9Citation - Scopus: 11Experimental Investigation of Spray Characteristics of Ethyl Esters in a Constant Volume Chamber(Springer, 2024) Ulu, A.; Yildiz, G.; Özkol, Ü.; Rodriguez, A.D.Abstract: Biodiesels are mainly produced via the utilization of methanol in transesterification, which is the widespread biodiesel production process. The majority of this methanol is currently obtained from fossil resources, i.e. coal and natural gas. However, in contrast with methanol, biomass-based ethanol can also be used to produce biodiesels; this could allow the production line to become fully renewable. This study aimed to investigate the spray characteristics of various ethyl ester type biodiesels derived from sunflower and corn oils in comparison to methyl esters based on the same feedstocks and reference petroleum-based diesel. Spray penetration length (SPL) and spray cone angle (SCA) were experimentally evaluated in a constant volume chamber allowing optical access, under chamber pressures of 0, 5, 10 and 15 bar and injection pressures of 600 and 800 bar. Sauter mean diameter (SMD) values were estimated by using an analytical correlation. Consequently, ethyl esters performed longer SPL (2.8–20%) and narrower SCA (5.1–19%) than diesel under ambient pressures of 5 and 10 bar. Although the SMD values of ethyl esters were 48% higher than diesel on average, their macroscopic spray characteristics were very similar to those of diesel under 15 bar chamber pressure. Moreover, ethyl esters were found to be very similar to methyl esters in terms of spray characteristics. The differences in SPL, SCA and SMD values for both types of biodiesels were lower than 4%. When considering the uncertainty (± 0.84%) and repeatability (±5%) ratios, the difference between the spray characteristics of methyl and ethyl esters was not major. Graphical abstract: [Figure not available: see fulltext.] © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Article Citation - WoS: 1Citation - Scopus: 1Experimental Investigation of Naca 4415 Airfoil Using Vibration Data for Stall Detection(Emerald Group Publishing, 2023) Ayaz Ümütlü, Hatice Cansu; Kıral, Zeki; Karadeniz, Ziya HaktanPurposeThe purpose of this study is to identify the possible relation between the vibration and the stall by using the vibration response of the airfoil. For this purpose, the root mean square values of the acceleration signals are evaluated to demonstrate the compatibility between the stall angles and the vibration levels. Design/methodology/approachAn experimental study is conducted on NACA 4415 airfoil at Reynolds numbers 69e3, 77e3 and 85e3. Experiments are performed from 0 & DEG; to 25 & DEG; of the angles of attack (AoA) for each Reynolds number condition. To observe the change of the vibration values at the stall region clearly, experiments are performed with the AoA ranging from 10 & DEG; to 25 & DEG; in 1 & DEG; increments. Three acceleration sensors are used to obtain the vibration data. FindingsThe results show that the increase in the amplitude of the vibration is directly related to the decrease in lift. These findings indicate that this approach could be beneficial in detecting stall on airfoil-type structures. Originality/valueThis study proposes a new approach for detecting stall over the airfoil using the vibration data.Article Determining Suitable Regions for Potential Offshore Wind Farms in Bandırma Bay Using Multi-Criteria Method(Bandırma Onyedi Eylül Üniversitesi, 2021) Karipoğlu, Fatih; Öztürk, Samet; Genç, Mustafa SerdarWind energy is an environmentally friendly, profitable, and renewable energy resource. Wind energy eployment is increasing in the last two decades. In this paper, Bandırma bay which has a potential for offshore wind deployment is studied to determine the most suitable area in it and eventually potential offshore power capacity of the location is estimated. This study combines applications of Geographical Information System and Multi-Criteria- Decision-Making Methodology to obtain fast results supported with visual documentation. In this scope, eight standard criteria such as wind speed, water depth, bird migration lines are applied and nvestigated in detail by using Geographical Information System. It is found that there is sufficient wind speed t the shallow level of the sea. Consequently, two locations are found to be suitable; one is on the northwest and the other one is on the north east of Bandırma, with capacities of 72 MW and 48 MW, respectively.Conference Object Citation - Scopus: 11Wind-Solar Site Selection Using a Gis-Mcdm Approach With an Application in Kayseri Province/Turkey(Institute of Electrical and Electronics Engineers Inc., 2021) Genç, Mustafa Serdar; Karipoğlu, FatihRenewable and sustainable energy sources such as wind, biomass, geothermal and solar are defined as a less harmfully to environment than other fossil fuels reserves. At the last decade, the demand of energy because of the rising of industrialization and population is increasing in Turkey. Thus, investments on renewable energy sources especially wind and solar energy systems are increasing rapidly because of unlicensed energy production legislation published by Turkish Ministry of Energy and Natural Sources. Although Turkey has high solar and wind capacity, there has not been develop a tool to determine the suitable regions for hybrid energy systems. In this study, geographical information systems (GIS) and Multi-criteria-base method (MCDM) are used to determine the suitable regions for wind-solar hybrid energy systems of Kayseri Province under potential and environmental impacts. The results shows (2.080 km2) %12.3 of Kayseri is suitable for hybrid energy system investment. © 2021 IEEE.Article Citation - WoS: 1Performance Analysis of Thermal Storage Assisted Cooling Tower With Night Cooling(Gazi Üniversitesi, 2020) Ouedraogo, Kiswendsida Elias; Toprak, KasımAs global warming and water scarcity issues continue to grow, it is essential to increase resources efficiency for air conditioners and power plants. In order to increase the efficiency, the systems need to be modified to take the advantages of the low night temperature and thermal storage tanks. In this study, the low night temperature and thermal storage tanks effects on the cooling tower is studied using TRNSYS. Using a chiller operating from 8:00 to 16:00 as a case study, hot water from the condenser is partially stored on daytime and cooled slowly during the night. The storage tank volume is optimized by considering two big tanks and five small tanks. The results show that night cooling reduces cooling water temperature by 5.8 degrees C or 21.8% while the cooling efficiency is increased by 36%. The thermal storage tanks enable to have the low continuous flow rate and help to reduce the fan power by 67.1%. On the storage side, compared to two tanks system, the tanks volume is reduced by 16.5% when 5 tanks are used. In theory this reduction can go up to 50% by increasing the number of tanks and reducing their individual size.Article Omega type solar charge station(Croation Union of Mech. Engineers and Naval Architects, 2002) Atagündüz, GürbüzAcid rains, greenhouse effect, smog and depletion of ozone layer arc some of the factors, which lead to the air pollution in big cities all over in the world. One of ways to reduce the air pollution in big cities is the introduction of electro or hybrid cars. The present work deals with a photovoltaic charge station, which could be installed on a garage roof with the dimensions about three meters by six meters in order to charge the battery of an electro car. The present work consists of two parts. First part deals with the theoretical design of the charge station, which has been started during a research stay of the author* in Germany. The second part is an experimental work, completed at Izmir Institute of Technology as a MS-Thesis. The present work bases on the original idea of the author, used in a previous work for the field of heliostats of the Solar Thermal Power Plant in the University Ege. The idea is to create a fix mirror area, which should acts as if it were a sun-tracking array. The theoretical design work and the results of the experiments have shown that the idea is applicable also to photovoltaic fields.Conference Object Citation - WoS: 1Citation - Scopus: 3Green Smart Cities: Living Healthily With Every Breath(Institute of Electrical and Electronics Engineers Inc., 2019) Turhan, Cihan; Atalay, Ali Serdar; Gökçen Akkurt, GüldenFifty-four percent of the world's population lives in big cities and it is projected to increase to nearly 70% by 2050s. Rapid and dense urbanization leads to smart cities which improve the quality of lives of the citizens. Therefore, development of smart cities is becoming vital. The quality of the citizens is affected by many factors including poor air quality, increased pollutants and microclimates called urban heat islands. The URBAN GreenUP project, initiated in June 2017, is a project funded under the European Union's Horizon 2020 programme. The main objective of the project is the development, application and replication of re-naturing Urban Plans in a number of European cities. In this study, measurement of nature-based solutions for mitigation of urban heat island effect and improvement of air quality for Urban GreenUP project in Izmir, will be introduced.Article Citation - WoS: 7Inertia and Droop Controller for a Modern Variable Speed Wind Turbine To Provide Frequency Control in a Microgrid(Gazi Üniversitesi, 2020) Hassan, Ali; Altın, Müfit; Bingöl, FerhatThe increasing penetration of modern Variable Speed Wind Turbines (VSWTs) in microgrids creates the problem of frequency stabilization due to reduced inertia of the power system. To emulate the Inertia Response of the conventional synchronous machines, wind turbines can be provided with an inertia emulation controller. The modeling presented in this paper aims at equipping the modern Type D wind turbine with inertia response and primary frequency control (PFC) capabilities. Two controllers - inertial and droop, are implemented and their frequency control capabilities are compared in an isolated power system which consists of a conventional steam turbine generator and a wind farm. The results suggest that proposed controllers help in better frequency control performance in the microgrid.Book Part Citation - Scopus: 2Ventilation Strategies for the Preventive Conservation of Manuscripts in the Necip Paşa Library, Izmir, Turkey(Elsevier, 2018) Coşkun, Turgay; Şahin, Cem Doğan; Gülhan, Özcan; Durmuş Arsan, Zeynep; Gökçen Akkurt, GüldenLibraries are specific spaces in which the indoor microclimate should meet rigorous requirements such as the thermal comfort of humans and the conservation of books, manuscripts, and cultural property. An inadequate indoor microclimate (mainly temperature, relative humidity, and their fluctuations) in libraries may cause chemical, biological, and mechanical degradations in paper-based collections. In this chapter, the indoor microclimate of the Necip Paşa Library, the historic library located in Tire-Izmir, Turkey, is discussed from the perspective of the preventive conservation of manuscripts. The library, which has no active heating, cooling, and ventilation system, was modeled with the help of a building energy simulation tool, DesignBuilder. The indoor temperature and relative humidity were monitored throughout 1 year and the model was calibrated with respect to these measurements. To reduce the risks of the manuscripts degrading, ventilation strategies were proposed including natural and mechanical control. The results showed that risks of chemical degradation can be diminished to some extent. © 2018 Elsevier Inc. All rights reserved.Conference Object Citation - Scopus: 1Offshore Wind Energy Estimation in the Bay of Bengal With Satellite Wind Measurement(IEEE, 2019) Nadi, Navilla Rahman; Badger, Merete; Bingöl, FerhatThe objective of this paper is to obtain appropriate offshore location in the Bay of Bengal, Bangladesh for further development of wind energy. Through analyzing the previous published works, no offshore wind energy estimation has been found related to the Bay of Bengal. Therefore, this study can be claimed as the first footstep towards offshore wind energy analysis for this region. Generally, it is difficult to find offshore wind data relative to the wind turbine hub heights, thus a starting point is necessary to identify the possible wind power density of the region. In such scenario, Synthetic Aperture radars (SAR) have proven useful in previous studies. In this study, SAR based dataset- ENVISAT ASAR has been used for Wind Atlas generation of the Bay of Bengal. Furthermore, a comparative study has been performed with Global Wind Atlas (GWA) to determine a potential offshore wind farm production in a reasonable location at the bay. The annual energy production of that offshore windfarm has been analyzed by combining SAR, GWA and ASCAT datasets. Through ASAR based Wind Atlas and GWA comparison, some differences have been found where there are less samples from the ASAR datasets. Thus, Weibull statistical analysis are performed to have a better Weibull fitting and accurate estimation of Annual Energy production (AEP). The study summarizes that, satellite datasets can be a very useful method to detect potential zone if compared with any long time statistical result and bathymetry data together. © 2019 IEEE.