Master Degree / Yüksek Lisans Tezleri

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

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Author: search.filters.author.Gökçen Akkurt, GüldenPublisher: search.filters.publisher.Izmir Institute of Technology

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Now showing 1 - 10 of 23
  • Master Thesis
    Improvement of Indoor Air Quality in Classrooms Based on Age of Air Parameters and Fanger's Predicted Mean Vote Method
    (Izmir Institute of Technology, 2023) Yetiş, Ahmetcan; Gökçen Akkurt, Gülden; Karadeni̇z, Zi̇ya Haktan; Gökçen Akkurt, Gülden; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Indoor air quality in classrooms is an important research topic today. Studies have shown that poor or inadequate indoor air quality has negative effects on students' performance and active participation in classes. The aim of this study is to examine the local air velocity and air age parameters to determine the ventilation needs of crowded, but limited-sized classrooms that are not connected to a central ventilation system, and to investigate the applicability of ventilation systems that can provide adequate indoor air quality. In the study, a primary school classroom with a capacity of 30 students was examined. Ventilation requirement is determined per person according to "ASHRAE 62.1-2022" Standard and "Building Bulletin 101" directive. For ventilation of the classrooms, counter-fluid heat recovery ventilation units mounted embedded in the wall. It is aimed to reduce the total volume allocated for the ventilation device in the classroom compared to the use of a single device. To slow down fresh air entering the room at high speed and mix it before reaching breathing zone, blowing directions of the neighboring devices are intersected. With these information, a classroom model was created to be analyzed with the Computational Fluid Dynamics method. In addition, another classroom model was created for investigating personal ventilation scenario. By a comparative analysis, average air velocities, age of air values around heads of students and students' perception of indoor air quality according to Fanger's "Predicted Average Vote" method were investigated.
  • Master Thesis
    Experimental Investigation and Computational Fluid Dynamics (cfd) Analysis of Geothermal Sourced Hot Air Drying
    (Izmir Institute of Technology, 2022) Helvacı, Hüseyin Utku; Gökçen Akkurt, Gülden; Gökçen Akkurt, Gülden; Helvacı, Hüseyin Utku; 01. Izmir Institute of Technology; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering
    Drying is one of the oldest methods used to increase the product's shelf life and reduce transportation costs, consisting of heat and mass transfer between the product and the surrounding environment. One of the most common drying methods is hot air drying. The most critical parameters in hot air drying processes are drying air temperature, air velocity and relative humidity. Renewable energy resources can be used as heat/electricity in drying processes. Geothermal energy resources are highly suitable for hot air drying with their temperature compatibility and reliability. The geothermal resources in Turkey have a high potential for hot air drying. This Thesis examines tomato slices' quality parameters at different drying air temperatures and velocities. A cabinet-type geothermal sourced hot air dryer is installed in the Yenikale Heat Center of the Balcova-Narlidere Geothermal District Heating System in Izmir-Turkiye. Drying experiments are carried out at 40-60-80°C air temperatures and 0.5-1.5 m/s air velocities to examine their effects on drying kinetics and quality of dried tomatoes, such as pH, color, and moisture. With the help of the data obtained, drying time, drying rate, moisture rate, and effective diffusion coefficients are determined, and dimensionless moisture rate is modeled using thin layer models. Also, energy and exergy analyses are made for each experiment. Finally, experimental and simulation results are compared by using CFD to perform experimental design. The simulations created by using CFD are obtained in a much shorter time and more accurately since all materials used for the experiment are idealized.
  • Master Thesis
    Statistical Analysis of the Effect of Meteorological Parameters on Pm10
    (Izmir Institute of Technology, 2022) Gökçen Akkurt, Gülden; Turhan, Cihan; Gökçen Akkurt, Gülden; Turhan, Cihan; 03.10. Department of Mechanical Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Air pollution is a serious threat where the pollutants in the air in solid, liquid and gaseous states reach levels that would harm the natural balance of the environment and the lives of vital organisms. Especially in industrialized cities, in addition to the effects of urbanization, physical environment characteristics may also play a role in the formation of environmental problems. Therefore, it is of high importance to understand the characteristics of the natural environment in the studies on air quality, in order for urban spaces to be livable areas. In this study, the correlations between PM10 pollutant data and certain meteorological parameters that were obtained from 3 stations in İzmir province were statistically evaluated. PM10 data was studied according to pre-pandemic, mid-pandemic and post-pandemic periods between 2017–2021. Meteorological data was gathered for a twelve-month period between February 2021 and January 2022 and its effect on PM10 data for the same period was analyzed. In the statistical analysis that was performed via Minitab software, hourly average data of PM10 was the dependent variable; temperature, relative humidity, and wind speed and direction were the independent variables. In the analysis that Pairwise Pearson Correlation Coefficient (r) was used, the most significant correlation was found to be between relative humidity and wind speed.
  • Master Thesis
    Energy Performance Analysis and Materials Characterization of Aerogel Insulation Blankets
    (Izmir Institute of Technology, 2022) Akkurt, Sedat; Gökçen Akkurt, Gülden; Gökçen Akkurt, Gülden; Akkurt, Sedat; 03.09. Department of Materials Science and Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    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
    The Effect of Restoration Interventions on the Indoor Climate of Historic Buildings: Case Study of Tire Necip Paşa Library, İzmir, Turkey
    (Izmir Institute of Technology, 2022) Gökçen Akkurt, Gülden; Durmuş Arsan, Zeynep; Durmuş Arsan, Zeynep; Gökçen Akkurt, Gülden; 02.02. Department of Architecture; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology; 02. Faculty of Architecture
    Libraries are collections of recorded information which can host cultural heritage values that must be protected against mechanical, chemical and biological degradation. To prevent degradations, libraries require stable indoor climates with minimal temperature and relative humidity fluctuations and low concentrations of indoor air pollutants. Aim of the thesis is to investigate if installing a HVAC system is effective in improving the indoor climate of a historic library as a long-term preventive conservation method on the preservation of paper-based collections. Tire Necip Paşa Library in İzmir was selected as the case building which underwent restoration and a HVAC system integration in 2015. Library’s indoor climate was investigated before 2015 which allowed the comparison of pre- and post-restoration periods. Within the scope of this thesis, library was monitored at five locations between 2019-2021. 2019-2020 monitoring results were compared to pre-restoration monitoring results in terms of degradation risks and ASHRAE Chapter 23 control classes. Pre- and post-restoration indoor climates satisfied A1 and AA control classes, respectively. While there were mechanical and chemical degradation risks before restoration, no risk was observed post-restoration. There was no biological degradation risk during either periods. Additionally air pollutants were sampled during summer and winter of 2020-2021 which showed high SO2 and NO2 concentrations. Lastly the BES model of library was prepared and calibrated to investigate if existing HVAC system will continue to provide a stable indoor climate on future. The results of 2050 and 2080 simulations showed that HVAC system will struggle to provide a stable indoor climate.
  • Master Thesis
    Wind Turbine Power Curve Update Based on Atmospheric Conditions and Structural Fatigue
    (Izmir Institute of Technology, 2020) Bingöl, Ferhat; Gökçen Akkurt, Gülden; Bingöl, Ferhat; Gökçen Akkurt, Gülden; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Wind energy is still developing industry and people who work in this industry working hard to accomplish the difficulties. Problems are not arise only by nature of wind but technological developments, methods and even market pressure itself. Wind turbine theoretical power curves are given only for certain conditions and one can easily say that those conditions are not met in real sites. This difference generates a uncertainty in AEP calculations thus financial models become less reliable. Shifting power curve by taking atmospheric effects into account will give more realistic power curve thus more accurate AEP and financial models. In this study, effects of atmospheric conditions and correction methods on NREL 5MW wind turbines power curve have been investigated and importance of corrected power curve has been discussed.
  • Master Thesis
    Natural Ventilation Design for Historic Libraries With Cfd (computational Fluid Dynamics) Simulation
    (Izmir Institute of Technology, 2019) Gülhan, Özcan; Gökçen Akkurt, Gülden; Gökçen Akkurt, Gülden; Erek, Aytunç; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Libraries accumulate and protect written and printed works that make permanent knowledge and cultures have been accumulated throughout human history. Paper-based collections kept in libraries are the heritage of humanity. They are under risk of mechanical, biological and chemical degradation over the years caused by the fluctuations in temperature and relative humidity values and inability to control these values. The aim of the Thesis is to reduce degradation risks on paper-based collections in historic libraries by providing preventive conservation without damaging the structure of the building. The historic Necip Paşa Library which is home for 1147 manuscripts was chosen as a case study. In order to provide preventive conservation for manuscripts, firstly indoor microclimatic data were collected for one year and analyzed to observe the risks that may cause degradation types on manuscripts. Only chemical degradation risk was detected. Window controlled seven natural ventilation scenarios were developed to reduce the risk. Finally, ventilation scenarios were analyzed by Ansys Fluent 17.1. Computational Fluid Dynamics (CFD) modelling was used to observe the effect of natural ventilation scenarios on indoor relative humidity according to outdoor relative humidity and wind direction. Finally, k-? turbulence model was used in CFD analysis. Results shows that during the high chemical degradation risk period (May-October), outdoor air temperature and relative humidity are suitable only 7.53% of the total time which allows appropriate natural ventilation. As a conclusion, natural ventilation is not enough to decrease chemical degradation risk totally for the Library. Therefore, additional mechanical ventilation is required.
  • Master Thesis
    An Investigation of Transient Water Vapor Migration in Building External Walls
    (Izmir Institute of Technology, 2019) Turgut, Çiğdem; Başaran, Tahsin; Gökçen Akkurt, Gülden; Başaran, Tahsin; Gökçen Akkurt, Gülden; 02.02. Department of Architecture; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology; 02. Faculty of Architecture
    Building 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
    Thermal Comfort Analysis of Historical Mosques, Case Study: the Ulu Mosque, Manisa, Turkey
    (Izmir Institute of Technology, 2019) Diler, Yusuf; Gökçen Akkurt, Gülden; Turhan, Cihan; Gökçen Akkurt, Gülden; Turhan, Cihan; 03.10. Department of Mechanical Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Mosques are sanctuary places for Muslims where they can communicate with each other and perform their religious activities. Mosques differ from other building types in terms of occupancy period during a day with their unique function and intermittent operating schedule. Historical mosques with cultural heritage value, contain lots of artworks and represent Turkish culture for centuries. These mosques are originally built and serve without heating, cooling and mechanical ventilation systems. In this thesis, a systematic approach on monitoring and evaluating the microclimate and thermal comfort of historical mosques has been developed. This approach consists of two phases: detailed data collection and developing a dynamic building energy model. As a case study, The Ulu Mosque was monitored between 2015 and 2018. Thermal comfort evaluation of the mosque during worship periods were conducted based on the method provided by EN ISO 7730 standard. A dynamic Building Energy Performance Software, is used to model the mosque, and the model was calibrated by hourly indoor temperature data. The calibrated model, which meets ASHRAE 14 requirements, is used to develop retrofitting proposals. Thirteen different scenarios were proposed to improve thermal comfort during worship periods. The results were then evaluated according to EN 16883 standard in terms of the conservation of cultural heritage. Electric radiator heating with intermittent operating schedules was obtained as the best options to protect cultural heritage, while decreasing dissatisfaction level from 45% to 10% in winter months. Additionally, comparing with continuous operating schedule, intermittent operation saves 46.9% energy.
  • Master Thesis
    Hybrid Energy Capacity of Turkey for Small and Micro Scale Energy Production
    (Izmir Institute of Technology, 2017) Yıldız, Mustafa; Bingöl, Ferhat; Gökçen Akkurt, Gülden; Bingöl, Ferhat; Gökçen Akkurt, Gülden; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Turkish state has opened a new possibility on investing small or micro scale energy production without license in 2014. This is a new step in Turkish energy market and two renewable energy sources are considered to be the main interest; wind and solar. Although there are studies covering both technology separately, currently there is no hybrid system assessment methodology and results for the country. This thesis aims to create a quantified hybrid energy capacity of Turkey. The study will include total energy capacity of a given location based on small scale wind and solar and furthermore would be able to suggest an optimum balance between these two sources to get the maximum production capacity out. The study does not cover areas that such investment cannot be done; environmental protected areas, historical places, city centers etc.