Master Degree / Yüksek Lisans Tezleri

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

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Access Right: Open AccessAuthor: search.filters.author.Helvacı, Hüseyin Utku

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  • Master Thesis
    Modeling and Thermo-Economic Analysis of a Photovoltaic-Battery Hybrid Energy System: a Case Study in Yenikale Geothermal Heat Center
    (01. Izmir Institute of Technology, 2023) Gökçen Akkurt, Gülden; Helvacı, Hüseyin Utku; Gökçen Akkurt, Gülden; Helvacı, Hüseyin Utku; 01. Izmir Institute of Technology; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering
    Water is vital for agriculture accounting 50-70% of the total global use of fresh water for irrigation. Geothermal water as a renewable energy source is used to generate electricity, heat and cool. The remaining water can be desalinated to be used for agricultural irrigation. Energy demand of desalination systems is high and mostly rely on fossil fuels increasing cost and greenhouse gas emissions. Thus, renewable energy use in desalination process is increasing. Based on a research project, a pilot desalination system is installed in Yenikale Heat Center of Balcova-Narlidere Geothermal District Heating System to desalinate geothermal water and use for agricultural irrigation. The desalination system is powered by a solar PV system which meets energy need entirely in summer but only 30-50% in winter. The remaining energy need is supplied from the grid. The aim of this study is to maximize the utilization of solar energy for the desalination process while minimizing reliance on the grid. To achieve this objective, three different scenarios are analyzed based on three different solar radiation values of 2021 integrating a battery system. For each scenario; first, battery capacities and the number of PV panels are determined. Then, energy, exergy and exergo-economic analysis are conducted. The parameters calculated in economic analysis are net present value, payback period and cost of energy production. One of the main results obtained is the unit energy cost for solar driven desalination system 0.28 $/kWh which is in a good agreement with the literature (0.214-0.23 $/kWh).
  • Master Thesis
    Design and Tests of a Geothermal Dryer and Determination of Quality Parameters of Dried Product
    (Izmir Institute of Technology, 2012) Helvacı, Hüseyin Utku; Helvacı, Hüseyin Utku; Gökçen Akkurt, Gülden; Gökçen Akkurt, Gülden; 01. Izmir Institute of Technology; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering
    Drying which is a heat and mass transfer process between the product surface and its surrounding medium and within the product is practised to enhance the storage life and reduce transportation costs of products. Olive leaves are the plants which have been used for medicinal purposes are often dried before use. Renewable energy sources such as geothermal energy can be used in drying processes as heat source besides fossil fuels. The temperature and the thermal potential of geothermal resources in Turkey is high enough to be used in drying process. In this thesis, a geothermal cabinet type drier was constructed and placed in Balcova-Narlidere geothermal field. To be able to determine drying parameters (temperature and velocity) and whose effects on drying kinetics of olive leaves and on the quality parameters of dried olive leaves (antioxidant content and phenolic content), drying experiments were carried out at three different air temperatures (40, 50 and 60 °C) and at three air velocities (0.5, 1, 1.5 m/s). During the experiments temperature, relative humidity and velocity of drying air was measured and recorded. Then, using the measured data drying time, drying rate, moisture ratio and effective diffusivity was determined and moisture ratio was modelled using thin-layer models. The quality parameters which are total antioxidant activity and total phenolic content were determined using spectrophotometric techniques. To evaluate the performance of the dryer, energy and exergy analyses were conducted. The drying time was determined as 240 – 555 min. (4 – 10) hour which is quite short comparing with open air sun drying. Optimum drying air temperature and velocity which gives the minimum total phenolic content and antioxidant loss value were determined by response surface methodology as 50 °C and 1 m/s, respectively. The energy utilization was found 0.3316 kW and the energy utilization ratios were found 50.36% and 7.96% for the case at drying air is re-circulated and the case at drying air was no re-circulated, respectively.