Sürdürülebilir Yeşil Kampüs Koleksiyonu / Sustainable Green Campus Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7755
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Master Thesis An Experimental Investigation Into the Effects of High Thermal Mass on Building Performance(Izmir Institute of Technology, 2019) Karataş, Özgür; Başaran, Tahsin; Başaran, Tahsin; 02.02. Department of Architecture; 02. Faculty of Architecture; 01. Izmir Institute of TechnologyThe focus on energy efficiency in buildings has contributed to the increased interest in vernacular architecture using locally available materials. Monotype architecture has spread across Anatolia during last century despite builders having centuries of knowledge of vernacular dwelling. Climatic conditions are specific to geographical locations, therefore the architectural solutions respecting climatic conditions are also specific. Local construction materials are in harmony with the surroundings because they have previously been part of the current environment. The main aim of this thesis is to investigate and simulate the effects of high thermal mass on the thermal environment of cave dwellings. The case study was undertaken in a cave dwelling carved out of a fairy chimney in Ürgüp, Cappadocia. Data loggers were placed in the dwelling to observe the annual temperature and relative humidity fluctuations. Measurements showed that the interior temperature fluctuated around 18°C in January and 20°C in July, and the relative humidity fluctuated around 70% in January and 65% in July. These measurements showed that the interior conditions were thermally comfortable as a result of the high thermal mass of the cave dwelling. DesignBuilder software was used to simulate the thermal behaviour of the cave dwelling. The thermal conductivity, specific heat and density of the main material, volcanic tuff rock, were measured and defined in DesignBuilder. After defining all the inputs and boundary conditions, the numerical results obtained from the DesignBuilder provided thermal outputs which agreed with the experimental results.Master Thesis Natural Groundwater Recharge in the Alaşehir Sub-Basin (gediz Basin, Turkey)(Izmir Institute of Technology, 2018) Tonkul, Serhat; Tonkul, Serhat; Baba, Alper; Baba, Alper; Şimşek, Celalettin; 03.06. Department of Energy Systems Engineering; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe increase in water utilization due to climate change in recent years, as well as excessively growing population causes to an increase in usage of groundwater and threatens water resources. Dams and artificial lakes are being constructed to ensure the sustainability of water resources, but there is much evaporation on large surface of these structures. Due to reason that the evaporation losses are not experienced, the groundwater recharge by direct rainfall becomes important. Groundwater recharge protects the water without too much evaporation in the basins and increases the potential of water resources and ensures sustainability. The aim of this study is to determine alluvial aquifer recharge in Alaşehir (Manisa) sub-basin using numerical and chemical methods. In addition to this aim, the mechanism of mixing of groundwater and geothermal fluid has also been examined. The Gediz Basin, located in the west of Turkey constitutes 2% of the country, has an important groundwater potential in the area where it is used. The Alasehir sub-basin, located in the southeast of the Gediz Basin and having extensive withdrawal for irrigation, constitutes the study area. Alluvial aquifer is the main groundwater bearing lithological unit in the plain. Twenty-five research wells, which is ranging from 20 m to 50 m in depth, were opened for the calculation of the recharge of the aquifer. Soil characterization was done on the core samples and the aquifer characterization was performed and the alluvial aquifer recharge was calculated. As a result, the recharge value of annual precipitation is range from 21.78 mm to 68.52 mm and average recharge from precipitation is 43.09 mm in the wells which are opened into the alluvium aquifer. According to the numerical model, this amount of recharge corresponds to 10% of the amount of annual rainfall. This estimated recharge ratio directly represents recharge from precipitation into the aquifer. According to the results of the chemical method, it is understood that the average recharge value from precipitation is 16.38%. In addition, the mixing ratio of the groundwater and geothermal fluid is 17% in the sub-basin. Keywords Aquifer Characterization, Alaşehir, Precipitation Recharge, Numerical ModellingMaster Thesis Steady and Unsteady Aerodynamic Analysis of the Airfoil Profiles by Using Vortex Singularity Elements(Izmir Institute of Technology, 2018) Elmacı, Salim Cenk; Özbahçeci, Bergüzar; Özkol, Ünver; Özkol, Ünver; Özbahçeci, Bergüzar; 03.10. Department of Mechanical Engineering; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe 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 Effects of Grid Design on Lead-Acid Battery Performance(Izmir Institute of Technology, 2017) İşler, Tuğçe; Top, Ayben; Ebil, Özgenç; Ebil, Özgenç; Top, Ayben; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn today’s world, approximately 88 percent of the total energy demand is supplied by fossil fuels; however, it has become clear that; other energy sources are needed due to limited fossil fuels. The demand for energy can most effectively be filled by renewable energy sources as installed energy storage capacity is growing rapidly. If renewable energy sources advance enough to fulfill the high demand, earth-friendly, clean and sustainable energy will help to protect the environment, thus ensuring a healthier life for future generations. Energy storage systems are essential in this endeavor, and in order to become more prevalent, storage systems for renewable energy sources must supply electricity without interruption as much as possible. As an electrochemical storage, a battery with a high level of performance, high energy density and life cycle could offer a viable solution for electricity storage provided that battery cost should be economically viable. This thesis aims to improve the geometry of the grid used in lead acid batteries in order to obtain a more uniform current and potential distribution, and minimize the potential drop for improved battery performance. A 3D mathematical model was developed using finite element method to evaluate the behavior of the grid under various conditions. Five different porous grid geometries were simulated under different loads and optimum grid geometry was identified. The 3D mathematical model of the lead-acid battery based on finite element method was simulated under certain conditions in order to evaluate the effect of grid geometry on battery performance.Master Thesis Cogeneration Sustainability Study for the Izmir Institute of Technology(Izmir Institute of Technology, 2017) Ahmad, Awais; Rodriguez, Alvaro Diez; Rodriguez, Alvaro Diez; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study, feasibility of Cogeneration/Combined Cycle System will be evaluated for the Izmir Institute of Technology. Turkish Energy Policy lacks some key factors which need to be highlighted for achieving Energy targets. The first aim of this study is to compare the policies and implementation of combined cycle systems of Turkey with Europe and to analyze the steps carried out by European Countries to achieve sustainability. The main objective of this study includes the implementation of a combined cycle system based on the data collection from the authorities of the Institute to analyze the deficiencies of existing system and to propose a more efficient system for meeting the energy demand. Two systems were taken in consideration, a gas turbine and a reciprocating engine based combined cycle system, detailed energy analysis with emissions and cost analysis were presented to determine what case provides the best solution to meet the energy demand.Master Thesis Processing and Characterization of High Performance Piping Materials for Geothermal Applications(Izmir Institute of Technology, 2003) Toğulga, Murat; Tanoğlu, Metin; Tanoğlu, Metin; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyPolymer composite based pipes are being recently utilized in transportation of geothermal fluids.The utilization of composites is due to their resistance to aggressive chemicals and hot-wet environment with relatively high specific strength and design flexibility.Exposure of materials to wide range of temperatures and humidity level, while under the action of load, may degrade them and cause to severe reduction in their properties and service life.Understanding the complex degradation mechanism of the composites exposed to a variety of temperature and fluid chemistry (including geothermal fluid) is essential to improve their durability.This research focuses on the investigation of interactions between geothermal fluid and composite piping materials made of various matrices and the mechanism of degradation in these composites.The matrix materials include polyester, epoxy and graphite particle added epoxy materials.In this study, E-glass fiber reinforced polymer composites were fabricated by employing filament winding and tube rolling techniques.Fabricated composites and neat polymers were exposed to dry environment, distilled water and geothermal fluid of Balçova geothermal field until the saturation of weight gains due to water uptakes.In addition, the specimens with neat polymers were prepared to simulate and follow the degradation of matrix materials under hot-wet environments.Once the saturation occurred, the specimens were subjected compressive mechanical testing.For both dry and wet specimens, the mechanical testing was performed to obtain stress-strain behavior, modulus of elasticity, strain at failure values and energy absorption during the loading.The results were compared to evaluate the degradation of the properties due to various exposures.Moreover, the thermal conductivity of the various composites fabricated in this research was measured to determine the heat losses and temperature distribution within the materials.The temperature distribution within the cross-section of the pipes for various materials was analyzed using a finite element-modeling tool, LUSAS for uninsulated pipes.The heat loss occurring during the transportation of hot geothermal fluid was calculated as a case study to compare composites and traditional metal piping.It was found that polyester composite pipes have higher mechanical performance under axial and radial compression as compared to the composite with epoxy matrices. For all the composite types, some considerable degradations were measured due to exposure to hot-wet environments.The extend of degradation was less for graphite particles added epoxy composite pipes that exhibited the lowest water uptake values. The graphite particles incorporated into the matrix affected the water uptake and thermal conductivity of the epoxy.The water uptake of polyester matrix composite pipes was the highest that might be related to the most extensive degradation of polyester based composite.Moreover, it was found that the thermal conductivity of the composites is much lower than traditional materials.The graphite particles cause reduction in thermal conductivity, simultaneously in heat loss for uninsulated pipes.However, if the isolation is used, heat loss is not sensitive to pipe material.