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.Conference Object Citation - Scopus: 2Co2 Capture by Pei-Impregnated Alumina Sorbents(ISRES Publishing, 2023) Turgut, Furkan; Kostik, Simge; Erdoğan, Barış; Çağlar, BaşarDirect air capture (DAC) or direct CO2 extraction from ambient air is a promising approach to reduce greenhouse gas emissions caused by both distributed (location independent) and point sources (location specific). Solid sorbents have been considered as more effective for DAC compared to the liquid counterpart since they have a faster kinetic and avoid volatile and heat losses due to the absence of evaporation of liquids. In this study, the alumina-supported polyethyleneimine (PEI) material was chosen as solid sorbents and their CO2 capture performance for different PEI loadings (20, 35, 50 wt%), flow rate (15, 30, 45 L/h) and adsorption temperatures (30, 40, 50, 60 °C) was investigated. Sorbents were prepared by using wetness impregnation method and their physical and chemical properties were characterized by several techniques such as N2 adsorption-desorption (surface area, pore size and volume), Scanning Electron Microscopy-SEM (surface morphology, surface chemical composition). The CO2 capture performance of sorbents were analyzed under different CO2 concentrations and the cyclic (adsorption-desorption) behavior of the sorbents were tested. The results show that alumina-supported PEI adsorbents are promising materials for CO2 capture with high CO2 adsorption capacity and stability. © 2023 Published by ISRES.Book Part Citation - Scopus: 4Investigation of a New Methanol, Hydrogen, and Electricity Production System Based on Carbon Capture and Utilization(Springer, 2023) Khani, Leyla; Mohammadpourfard, MousaIt is well-known that clean energy transition requires low carbon emission. The increase in population, economic development, and human welfare demands has led to a rise in energy consumption, mainly supplied by fossil fuels. However, burning fossil fuels produces carbon dioxide, which is a greenhouse gas and a contributor to environmental problems. Therefore, carbon capture and conversion to different products have gained attention. On the other hand, combining two or more different thermodynamic systems for simultaneous production of various demands from one energy source looks reasonable. In this regard, a new trigeneration system is proposed to decrease atmospheric carbon dioxide emission and produce methanol, hydrogen, and power. A flue gas stream with a defined composition, solar energy, and atmospheric air are the system’s inlets. Then, mass, energy, and exergy balance equations are applied for each subsystem to investigate the system’s thermodynamic performance. Also, the effect of changing operating parameters on the performance of each subsystem is studied. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.Book Part Citation - Scopus: 1A New Stable Solar System for Electricity, Cooling, Heating, and Potable Water Production in Sunny Coastal Areas(Springer, 2023) Khani, Leyla; Mohammadpourfard, MousaNowadays, more attention is paid to provide clean energy products with low environmental pollution in a decentralized way. Many coastal rural areas suffer from freshwater and electricity scarcity, especially in hot weather condition. Meanwhile, these regions have a great access to intense solar radiation and seawater. Hence, it seems logical to use the available solar energy in those places to provide to necessities like power, heating, and cooling. A new solar cooling, power, heating, and freshwater production system is designed, evaluated, and optimized in this research. The proposed system is composed of several subsystems to generate each product with high efficiency and reliability. Solar energy is unavailable at night, so molten salt energy storage is used to establish the steady operation of the system. Then, the system is evaluated from thermodynamic and exergoeconomic viewpoints, and a parametric study is accomplished to study the effect on the system performance of key variables. In the end, the system is optimized to determine its best operating condition for different cases. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.Article Citation - Scopus: 21The Developing Flow Characteristics of Water - Ethylene Glycol Mixture Based Fe3o4 Nanofluids in Eccentric Annular Ducts in Low Temperature Applications(Elsevier, 2022) Çobanoğlu, Nur; Banisharif, Alireza; Estelle, Patrice; Karadeniz, Ziya HaktanNatural circulation loops with double pipe heat exchangers at heating and cooling ends have a potential to be used in the refrigeration systems as an alternative to suction line heat exchangers. The heat transfer capability of such natural circulation loops depends on the geometrical parameters as well as thermophysical properties of the working fluid. This study aims to investigate the effect of water-ethylene glycol mixture based Fe3O4 nanofluids (0.01, 0.05 and 0.1 vol.%) on the annular flow propagation and heat transfer in the annuli of double pipe heat exchanger at low pressure side of the refrigeration cycle. In addition to increased non-dimensional velocity values due to the lower viscosity and higher non-dimensional temperature values with expanded temperature gradient, improved heat transfer by nanofluids shows that they can be used as secondary heat transfer fluids at low-pressure side in refrigeration systems. Although the maximum transferred (13.6% improvement compared to base fluid) heat observed for the highest concentration, the nanofluids with smallest concentration has the minimum pressure drop value (25% reduction compared to base fluid) and the highest performance evaluation criteria (PEC) value (PEC = 1.08) with tiny increase in exergy destruction (1.45% compared to base fluid)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.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.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 Molecular Dynamics Study of the Thermal Conductivity of Graphene Coated Copper(Avestia Publishing, 2019) Toprak, Kasım; Ersavaş, GizemIn this study, the thermal conductivity of various size of pure copper, pure graphene and, different number of layer graphene coated copper models are studied using non-equilibrium molecular dynamics (NEMD) simulations. Our findings show that the thermal conductivity of graphene coated copper is higher than the uncoated ones. Furthermore, results also indicate that single layer graphene (SLG) model has the highest thermal conductivity as compared to the other model. Even though multiple layer graphene (MLG) has lower thermal conductivity value compare to SLG, this study shows that the thermal conductivity of MLG coated copper has higher thermal conductivity than SLG coated one. The most important finding in this study suggests that the thermal conductivity of copper can be improved using high thermal conductivity materials like graphene. © 2019, Avestia Publishing.