Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Now showing 1 - 6 of 6
  • Master Thesis
    Investigation of Windshield Defogging and Defrosting Designs To Decrease Energy Consumption in Vehicles
    (01. Izmir Institute of Technology, 2023) Ediz, Fatih; Çetkin, Erdal
    Fogging and icing of windshields are general problems that affect driving safety and energy consumption. The aim of this study is to improve the truck windshield defogging system and reduce energy consumption. Firstly, we investigated the effects of vent position and width relative to the glass. In the first stage, we performed analysis on the truck xz plane (2D). We preferred this method to quickly see the effect of vent changes. In the second stage, we applied the modification parameters to the 3D duct model. In both studies, we determined that the independent variables had a statistically significant effect on the dependent variable and determined the parameters with the highest desirability value by using the Analysis of Variance method. Secondly, we added various separators to the duct model. We investigated the total mass flow rate coming to the driver's side with total pressure drop. In this thesis, we used the Eulerian Wall Film (EWF) Model to model the defogging phenomenon on windshields. In the EWF model, the wall film is treated as a separate fluid phase, and the conservation equations for mass, momentum, and energy are solved separately for each fluid phase. As a result, we applied the obtained data to the current design. Windshield defogging performance has improved in the optimization model. The average film thickness in region A decreased by 8.2% compared to the current model, while the average film thickness in region B decreased by 48.1%.
  • Master Thesis
    Citation - Scopus: 21
    Multi-Objective Evolutionary Optimization of Photovoltaic Glass for Thermal, Daylight, and Energy Consideration
    (01. Izmir Institute of Technology, 2023) Taşer, Aybüke; Kazanasmaz, Zehra Tuğçe; Kundakcı Koyunbaba, Başak
    As the industry has expanded and the population has increased recently, so have the World's energy consumption and greenhouse gas emissions. Buildings are responsible for almost 40% of this consumption and emissions. They should be designed following energy-efficient and sustainable strategies. One of the most practical methods for increasing building energy efficiency and reducing environmental effects is building-integrated photovoltaic systems, which use solar energy to generate electricity on-site. This thesis explores the potential of photovoltaic glass technology in an architecture studio at the Izmir Institute of Technology Campus in Izmir, Turkey. The initial part of the study uses simulation modeling and field measurements in three scenarios to test the benefits of this technology in terms of thermal and lighting energy consumption and comfort levels. Scenarios included amorphous silicon thin-film modules in three transmittance values modeled in existing windows. Research findings propose that photovoltaic glasses have the potential to balance the room's lighting loads in a range between 15.1-and 20.3%. They improved occupant thermal and visual comfort by preventing overheating and glare risks. They also decreased cooling loads. Then, the study uses a genetic optimization algorithm to explore the optimum potential of the system in terms of annual energy consumption and daylight performance. Design variables are the window-to-wall ratio (i.e., window size and location) and amorphous-silicon thin-film solar cell transmittance to generate optimum Pareto-front solutions for the case building. Optimization objectives are minimizing annual thermal (i.e., heating and cooling) loads and maximizing Spatial Daylight Autonomy. Optimized results of Low-E semi-transparent amorphous-silicon photovoltaic modules applied on the window surface show that the Spatial Daylight Autonomy is increased to 82% with reduced glare risk and higher visual comfort for the occupants. Photovoltaic modules helped reduce the room's seasonal and annual lighting loads by up to 26.7%. Compared to non-optimized photovoltaic glass, they provide 23.2% more annual electrical energy.
  • Master Thesis
    Energy Performance Analysis and Materials Characterization of Aerogel Insulation Blankets
    (Izmir Institute of Technology, 2022) Alan, Selena; Gökçen Akkurt, Gülden; Akkurt, Sedat
    İzmir Geothermal Energy Inc. is a geothermal district heating company in İzmirTurkey that circulates hot water throughout the district via a 450 km of piping system and with the help of valves, pipes, and heat exchangers. As the distance traveled by the hot water is excessively long, heat losses are common. Rock wool is used as thermal insulation material, but the performance degraded over time because of water leakage. Instead of rock wool, aerogel insulation blanket use is evaluated in this study. Rock wool and three different aerogel insulation blankets are comparatively studied to assess their structures and thermal performances in two ways: the first is the characterization of materials by various physical and chemical analysis methods in the IZTECH-Integrated Research Center. The second way is to assemble a test setup on-site and make thermal measurements on the test setup for each aerogel insulation material, rock wool, and bare pipe. Heat loss calculations were conducted by EES software. The results are compared based on each characterization and thermal performance calculation. The thermal conductivity values of the insulation materials were calculated. Nonwetting properties were also checked to understand their hygrothermal properties. Compared with bare pipe, with the 10 mm thickness, rock wool decreases heat loss by 48-52%, and with the 10 mm thickness, the aerogel insulation blankets reduce heat loss by 57-61%. Finally, while aerogel insulation blankets have a better performance, they are more expensive than rock wool.
  • Master Thesis
    An Experimental Investigation Into the Effects of High Thermal Mass on Building Performance
    (Izmir Institute of Technology, 2019) Karataş, Özgür; Başaran, Tahsin
    The 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
    Event Distortion Based Clustering Algorithm for Energy Harvesting Wireless Sensor Networks
    (Izmir Institute of Technology, 2017) Al-Qamaji, Ali Mudheher Raghib Kafi; Atakan, Barış; Atakan, Barış
    Wireless Sensor Network (WSN) is a set of inexpensive densely deployed wireless sensor nodes with limited functionalities and scarcity in energies, whose observations are forwarded or relayed by intermediate nodes to the Base Station (BS). In the networks with densely deployed nodes, the observations are likely to be highly correlated in the space domain. This type of correlation is referred as spatial correlation, which produces unfavorable redundant readings causing energy wasting. In this thesis, the main task is to reduce these nodes that have redundant readings by using a clustering algorithm called Event Based Clustering (EDC) algorithm. The clustering algorithm is based on exploiting the spatial correlation that is used to cluster the sensor nodes. Exploiting spatial correlation is proposed by using Vector Quantization (VQ) with respect to the distortion constraints. Furthermore, this algorithm is applied for energy harvesting sensor nodes. Also, the inessential sensor nodes that have correlated readings are reduced for improving the Energy-Efficacy (EE) with acceptable level of event signal reconstruction distortion at the sink node. After applying the EDC algorithm, the communication model is changed from single-hop model to two-hop (clustered-network) model. Hence, a theoretical framework of distortion function, i.e., accuracy level, for both single-hop and two-hop communication models is derived. Then, single-hop and two-hop communication models are compared in terms of achieved distortion level, number of alive nodes, and energy consumption for different sizes of event area. Finally, the effects of various harvested energy level on the clustered-network is studied with respect to the same terms.
  • Master Thesis
    An Investigation of Transient Thermal Behaviors of Building External Walls
    (Izmir Institute of Technology, 2015) Pekdoğan, Tuğçe; Başaran, Tahsin
    Heat 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.