Master Degree / Yüksek Lisans Tezleri

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

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Access Right: Open AccessSubject: search.filters.subject.Thermal management

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  • Master Thesis
    Numerical Investigation of Thermal Management in Photovoltaic Cells With Phase Changing Materials (pcm) and High Conductivity Inserts
    (01. Izmir Institute of Technology, 2021) Çetkin, Erdal; Çetkin, Erdal; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Photovoltaic cells' electrical conversion efficiency from incident solar radiation heavily depends on the cell temperature. A novel thermal management strategy aimed at keeping the cell temperature in the same order to maximize PV cell electrical conversion efficiency is proposed in this study. The study compares four solar module configurations: a conventional photovoltaic module (PVT module), a hybrid of conventional with PCM (PVT/PCM-I), an internally finned configuration with PCM (PVT/PCM-II), and a configuration where the bottom surface of PVT/PCM-II was cooled via convection (PVT/PCM-III). The developed 3D numerical model was solved via ANSYS software involving the solar ray tracing radiation model for incident solar radiations and a transient melting-solidification thermo-fluid model for modeling of the PCM. Numerical results were validated by comparing them against experimental results published in the literature. Results show that the conversion efficiency of PV cells reaches 16.84%, 18.65%, 18.83%, and 18.98% after 120 minutes for PVT module, PVT/PCM-I, PVT/PCM-II, and PVT/PCM-III, respectively while the specific electrical power produced reaches 75.30W/m2, 83.39W/m2, 84.19W/m2, and 89.42W/m2 for solar radiation of 540W/m2 and 26°C ambient temperature. A 5 mm increase in the fin height for PVT/PCM-II results in a 0.22% increase in efficiency while a 0.5m/s increase in the inlet velocity of the cooling air for PVT/PCM-III results in about 0.06% efficiency increase. Furthermore, performance evaluation of PVT/PCM-III was carried out with sample weather data of the Indian Institute of Technology-Delhi and the Algiers site. The hourly average of overall conversion efficiency for the respective sites reaches 16.70% and 16.84% for a conventional PV module and 19.04% and 19.19% for PVT/PCM-III where the conversion efficiency increases by 14% and 13.7% respectively.
  • Master Thesis
    Numerical Investigation of Thermal Management for an Airfoil Profile To Prevent Ice Formation
    (Izmir Institute of Technology, 2019) Kök, Çağatay; Çetkin, Erdal; Çetkin, Erdal; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    In this study, we present a design alternative to prevent the icing of a wind turbine blade in the cold climate wind zones. The main objective is to create a thin film around the wing profile that can protect the surface from ice formation. In order to form this insulating layer, the leading edge, which is the region where the icing started first, the circular openings that could provide hot air to the outside of the wing, were added to geometries. By means of these openings, it has been tried to provide a solution that will prevent ice on the surface without the need to heat the entire wing. At the same time, the effect of these openings on the wing, the distance between the openings and the positions and diameters of the wings on the lifting performance of the wing were investigated. Throughout the study, the design parameters were all proportional to the chord length of the wing. In the model stage, instead of the entire wing, only one section of the wing was modeled using symmetry boundary conditions in order to use the existing limited computing power more efficiently. In this way, both the number of network elements and the calculation time can be modeled in such a way that the distance between the openings is equal to the width of the section. The results show that the lifting force, as can be expected, is small. As the width, i.e. the distance between the openings increased, the lifting force became more stable, while the film layer temperature decreased.