Master Degree / Yüksek Lisans Tezleri
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Master Thesis Bina Çatılarında Bir Boyutlu Zamana Bağlı Isı Transferinin Türkiye'nin Farklı İklim Koşulları için İncelenmesi(2025) Büyükyazıcı, Muhammed Samed; Başaran, TahsinBu tez çalışması, farklı iklim bölgelerinde yer alan konut çatılarında zamana bağlı bir boyutlu ısı iletimini analiz ederek, çatı tipinin, eğim açısının, yönlenmenin ve yalıtım düzeyinin ısı geçişine etkisini değerlendirmeyi amaçlamaktadır. Çalışma kapsamında; Türkiye'de farklı iklimsel özellikleri olan altı şehir, iki betonarme çatı tipi, iki eğim açısı, dört ana yön ve dört farklı yalıtım senaryosu dikkate alınmıştır. Çatı sistemlerindeki yalıtım katmanları, TS825 standardının öngördüğü U-value gereksinimlerini sağlayacak şekilde tanımlanmıştır. Dış hava sıcaklığı, güneş ışınımı ve etkin gökyüzü sıcaklığı zamana bağlı dış ortam koşulları olarak tanımlanırken iç ortam sıcaklığı ise sabit kabul edilmiştir. Bir boyutlu ısı transferi problemi, implicit sonlu farklar temelli bir sayısal yöntemle çözülmüştür. Ocak ve temmuz aylarının ortalamasını yansıtan 24 saatlik periyotlar incelenerek mevsimsel karşılaştırmalar yapılmıştır. Bulgular, yalıtım seviyesi arttıkça hem kış aylarında ısı kayıplarının hem de yaz aylarında ısı kazançlarının belirgin şekilde azaldığını göstermektedir. Yüksek yalıtımlı senaryoda q değerleri yalıtımsız duruma göre 88–92% oranında azalmış, iç mekânda daha kararlı bir sıcaklık dağılımı sağlanmıştır. Yönelime bağlı farklar 4–10 Wh/m²·gün seviyesine kadar düşmüş, mevcut TS825 standardı eski standarda göre 4–10% iyileşme sunmuştur. Doğu ve batı yönlenmeli eğimli çatılar; güneyle benzer değerler gösterirken, kuzey yönündeki 30° eğimli çatı ise diğer üç yönden yaklaşık 6-46% oranında ayrışmaktadır. Bu durum yönelime bağlı optimizasyon stratejilerinin önemini ortaya koymaktadır. Çalışma, iklimsel, yapısal ve yönelime bağlı parametrelerin birlikte değerlendirilmesinin enerji etkin çatı tasarımı açısından kritik olduğunu göstermektedir.Master Thesis An Investigation of Transient Water Vapor Migration in Building External Walls(Izmir Institute of Technology, 2019) Turgut, Çiğdem; Başaran, Tahsin; Gökçen Akkurt, GüldenBuilding envelope design is very important for energy efficiency in the building due to control the mass and energy transfer between the internal and external environments. Additionally, this performance is also important for obtaining indoor air quality and comfort conditions in the built environment. The study aims to analyze the heat and moisture performance of the different building exterior wall types composed of the different structural elements and insulation materials. Two different analysis models were used for this study. The objective of the thesis is to predict the physical, chemical and biological problems in the building envelope that will arise due to condensation in the design stage. So, saving cost and time will be provided to consumers. In the scope of the thesis, the heat and moisture performance of 21 different wall sections that composed commonly used structural body elements (concrete, brick and aerated concrete) and insulation materials (XPS, EPS and MW) in different insulation situations (internal insulation, external insulation and non-insulated situation) were analyzed in steady and transient regimes. The interlayers with a risk of condensation were determined in the result of this study. The results of the two different analysis methods were evaluated and the differences of the methods were revealed. As a result of the study, it has been shown that the placement of the insulation material on the exterior side is more suitable for moisture.Master Thesis Numerical Analysis of Thermal Performance of Glazing Systems(Izmir Institute of Technology, 2019) Şahin, Yağmur; Başaran, TahsinThermal performance of different glazing systems have been investigated with a comprehensive parametric study numerically. In order to analyze the heat transfer through the windows, CFD simulations have been performed considering many affecting parameters. The aim of the study is to determine the appropriate window configurations according to the different cities that have different climatic conditions of Turkey which are: Ağrı, Sivas, Amasya and İskenderun. For this purpose, the glazing part of the window has been analyzed because of having low thermal resistance due to the gap widths, temperature differences and the emissivity values. Four physical models of glazing systems were designed. The thickness of glazing units is 4 mm and the height is 1 m as a constant. For investigating the effect of the cavity dimension on the heat transfer, two gap widths usually used, are determined and combined in different ways which as 12–12 mm, 16–16 mm, 12–16 mm and 16–12 mm. Different boundary conditions are defined according to ambient temperature of inside and outside. Radiation heat transfer is included in the calculations and various low-e coatings are defined to analyze the radiation effect on the heat transfer coefficient. As a result of this study, temperature and velocity profiles are different in all scenarios. The effect of gap width on the U-value is more distinguished in the low temperature difference. Heat loss can be minimized significantly with using low-e material and the emissivity value is more effective on the wider gap widths. It is also shown that the optimum air layer thickness of the triple pane window differ from the temperature difference significantly. The highest U-values were obtained in 12-12 mm gap width glass. It was determined that the heat losses can be reduced by using 16-12 mm gap width glass about 2% and 8% in cold regions and in warm regions respectively.Master Thesis Improvement of the Thermal Performance of an Aluminium Window Frame With Cfd Analysis(Izmir Institute of Technology, 2019) Gökçen, Gökçe; Başaran, TahsinMost of the primary energy used in the world belongs to fossil fuels. Energyefficient activities are carried out in many different sectors in order to prevent the depletion of the reserves of these resources. The building sector is one of them and many different studies are being carried out to reduce the energy consumed in the buildings. Windows are the main unit of heat losses and gains in buildings. In literature, the main reasons for heat losses through windows are usually stated as glass units due to their large areas and relatively higher overall heat transfer coefficient. However, windows frames are as important as glass units because they also have higher heat transfer. Since the most commonly used material in window frames, which is aluminium, has the highest thermal conductivity value, this topic should be investigated. In this study, two different strategies are presented to improve the thermal transmittance of an aluminium frame without changing the frame geometry. The first strategy presented is the improvement of the gasket and thermal break materials in which high thermal conductivity materials are used which have a considerable impact on the thermal performance of aluminium window frames. The second strategy is to fill the cavities in aluminium profiles with polyurethane foam in order to reduce convection effects. Two dimensional CFD simulations of the aluminium window frame, modelled with information from the manufacturer, were used to investigate these improvement strategies. As a result of the study, the importance of thermal break and gasket materials used in the aluminium window frame has been seen and the thermal conductivity of these materials has a considerable effect on the thermal performance of the windows. Moreover, the polyurethane foam filled air cavities in the aluminium frame have positively affected the thermal performance of window as proposed and %29.44 improvements occurred.Master Thesis Effectiveness in Space and Energy Utilization in Hvac System Selection(Izmir Institute of Technology, 2019) Elbiz, Gizem; Başaran, TahsinIn Turkey, energy consumption for heating constitutes an important part of the total energy consumed. The choice of heating system and the preferences in the use of related energy sources, excessive energy consumption and environmental impact cause high costs and significant area losses. A large number of parameters must be evaluated for the correct system selection. These parameters determine the installation cost of the system, heating and cooling loads during the construction period, and the environmental impact of energy consumption. This study aims to obtain the most economical and environmental friendly energy resource in a housing structure and accordingly, heating system and the system spatial value. The use of fossil fuels such as coal, fuel oil and natural gas and the geothermal energy as a renewable energy source are planned to be investigated. The analysis was carried out on how the climate conditions and economic values of the provinces of İzmir, Balıkesir, Kütahya and Ağrı, which are located in different climatic regions will be effected and where direct use of geothermal energy is concerned, will affect the results of the different system usage. Life Cycle Cost assessment was performed to investigate the relationship between the initial investment in a housing structure and the use of energy source and system selection. Geothermal energy is the best source of energy both for installation and renewal and for fuel consumption and environmental purposes. Geothermal heat exchangers selected for the source take up 36 times less space than coal boilers, and the economic reflection of this area is approximate 8000 if given the example of İzmir province. While considering the environmental impacts, CO2 emissions of geothermal energy are 15 times less than natural gas and 50 times less than coal.Master Thesis An Experimental Investigation Into the Effects of High Thermal Mass on Building Performance(Izmir Institute of Technology, 2019) Karataş, Özgür; Başaran, TahsinThe 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 The Heating System of Turkish Bath(Izmir Institute of Technology, 2017) Çelikyürek, Cansu; Başaran, TahsinThe beginning of bathing action lies in the prehistoric times and the bathing had an important role in the daily life in the Hellenistic period for the first time. Romans, who had been influenced by the bath techniques in the Hellenistic period, improved architecture and heating system technologies of the baths and made them an important part of their life. The Roman bath culture that spread in Anatolia was turned by the influence of Turks into the Turkish bath and still goes on today. Because of the fact that, investigations are not enough about heating system of Turkish bath, to the best of the author’ knowledge, thermal analysis’ studies have not been done, the plan and projects of the heating systems of the bath and thermal conditions of the bath have not been investigated; extensive researches become necessary. On the other hand, energy efficient solutions with consideration of the environmental impact should be developed for historic bath buildings which are allowed for a restoration process. The study has been concentrated on the documentation of the information about the heating systems of a Turkish bath, therefore the Alibey bath from the Ottoman period; is chosen to investigate the use of heating systems from past to present. The study focuses on the evaluation of the collected information about the Alibey bath in order to examine the relationship between traditional heating systems and under floor heating systems of the Alibey bath. In the study, thermal analysis of the Alibey bath and the energy efficiency of two different systems are determined for different operating conditions by using the ANSYS Fluent commercial code. In addition to this, field surveys are composed of freehand sketches for architectural details, temperature distributions and flow analyses of different sections of the structure are examined. As a result of this study, two heating systems, old and new, are compared thermally. In the heating system with hypocaust, the amount of fuel to be consumed is relatively higher than the floor heating system. Besides, the temperature distribution in the floor heating system is more homogeneous than the hypocaust system.Master Thesis An Investigation of Transient Thermal Behaviors of Building External Walls(Izmir Institute of Technology, 2015) Pekdoğan, Tuğçe; Başaran, TahsinHeat transfer problem of the building opaque wall surfaces are highly important for providing thermal comfort for different climatic conditions and orientations. In this study, the insulation models with external, internal and center positioned insulation materials are parametrically analyzed regarding their time dependent thermal behaviors. One-dimensional time-dependent heat conduction equation is investigated by solving via implicit finite difference method for summer and winter climatic conditions; and north, south, east and west orientations. Meteorological data for Ankara, Erzurum, İstanbul and İzmir, which are cities with different climatic conditions, are used in these calculations. The results indicate that, sandwich wall insulated type gives more convenient results regarding the heating loads for winter and cooling loads for summer, for each investigated city and directions.Master Thesis Thermal and Physiological Responses of the Human Body During Exercise(Izmir Institute of Technology, 2015) Zora, Süleyman; Başaran, Tahsin; Çolakoğlu, Bekir MuzafferIn this study, the thermal behaviors of the athlete’s bodies were investigated with respect to thermal comfort and exercise intensity experimentally. The relation between Predicted Mean Vote (PMV) which is an thermal comfort index and Ratings of Perceived Exertion (RPE) that measures the exercise intensity and exhaustion level was evaluated statistically. The experiments were carried out with eleven subjects in a conditioned test chamber at School of Physical Education and Sports in Ege University with a bicycle ergometer in 2012 and 2013. The relation between PMV and RPE was analyzed statistically by SPSS and the average correlation coefficient was obtained -0,52. This result mentions that there are a negative moderately correlation. Moreover, the oxygen consumption rate and core body temperature which affect the exercise performance of athletes were divided two groups as high and low and statistically analysis were conducted. Accordingly, while the average correlation coefficient at high oxygen consumption rate group decreases -0,21, the average correlation coefficient at low oxygen consumption rate group increases -0,77. The level of correlation coefficient decreases at the subjects whose oxygen consumption rates are high. Similarly, while the average correlation coefficient at high core body temperature group decreases -0,36, the average correlation coefficient at low core body temperature group increases -0,70. The existed level of correlation coefficients increases at the subjects whose core body temperatures are low.Master Thesis Investigation of Oil Flow and Heat Transfer in Transformer Radiator(Izmir Institute of Technology, 2015) Kaymaz, Özben; Başaran, Tahsin; Erek, AytunçTransformer losses are produced by the current passing through resistance on the winding conductors. These losses are converted to heat energy as all electrical machines. Transformer life depends on the aging of cellulose-based insulation material in winding. Winding temperature must be kept below a certain temperature limit, because the excess heat in the windings directly accelerates the aging of insulation material. Oil-immersed transformers are cooled by using transformer oil. In this study, flow and heat transfer of transformer radiator filled with mineral oil, silicone oil and ester oil were investigated. Oil in radiator was modelled in 3D, thereby oil flow volume was created, heat transfer calculations were made with using different type transformer oils and investigation of flow behavior is studied. Temperature dependent density, thermal conductivity and viscosity values are obtained from oil suppliers. Transformer oil database was composed by using curve fitting methods in MathCAD Software to use in CFD (Computational Fluid Dynamics) analysis in Fluent software. Finally, the pressure differences were obtained for each oil type. According to the velocity versus pressure difference graph that was obtained from the results of this study, inertial resistance and viscous resistance could be described which are required in future studies to use porous medium approach. Number of elements and computation domain will be decreased by using porous medium approach, then complete transformer model could be analyzed. Additionally, thermal characteristics of transformer oils were obtained and compared in this study. Accordingly, natural ester oil had the best heat transfer and pressure drop.