Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 1Citation - Scopus: 1Energy and Exergy Analysis of a Geothermal Energy Sourced Hot-Air Drying System(Inderscience Enterprises, 2023) Helvacı, Hüseyin Utku; Gökçen Akkurt, Gülden; Keleş, Nazlı; Helvacı, Hüseyin Utku; Gökçen Akkurt, Gülden; 01. Izmir Institute of Technology; 03.06. Department of Energy Systems Engineering; 03. Faculty of EngineeringA geothermal energy-sourced drying system was tested for the thin-layer drying process of tomato slices at air temperatures of 40 degrees C, 50 degrees C and 60? and velocities of 0.5 m/s and 1.5 m/s to investigate system performance in terms of the first and second laws of thermodynamics. The energy and the exergy efficiency of the system were found to be 6.6% and 22.31%. The energy utilisation and energy utilisation ratio were calculated in the range of 1.271 kW-5.102 kW and 9.644%-39.56%, respectively. The exergy destruction, exergy efficiency and improvement potential of the drying chamber varied between 0.0198 kW-0.2621 kW, 59.74%-81.95% and 0.00486 kW-0.07396 kW, respectively.Article Citation - WoS: 38Citation - Scopus: 40Exergoeconomic Analysis and Optimization of a High-Efficient Multi-Generation System Powered by Sabalan (savalan) Geothermal Power Plant Including Branched Gax Cycle and Electrolyzer Unit(Elsevier, 2022) Seiiedhoseiny, Miryasin; Mohammadpourfard, Mousa; Gökçen Akkurt, Gülden; Gökçen Akkurt, Gülden; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyEmploying suitable subsystems to reach high efficiency and low cost in renewable-based power plants is more crucial. The geothermal energy heat source is located in many countries, but this has never been investigated to run a multi-generation system, including a branched GAX cycle and an electrolyzer. In this path, a high-efficient multi-generation system powered by a Sabalan (Savalan) geothermal power plant consisting of a single flash cycle, a branched GAX cycle, and an electrolyzer is presented and scrutinized from thermodynamic and exergoeconomic viewpoints. In the end, a two-objective optimization, by using the Total Unit Cost of Product (TUCP) and energy efficiency as objectives, is utilized to find the optimum operating conditions. Critiques and studies of variables reveal that the produced hydrogen rate remains unchanged at 5.655 kg/h by changing the degassing value and temperature of the generator, condenser 2, and evaporator. By increasing the flash tank pressure from 5.2 bar to 7 bar, the cooling and heating loads rise about 108.4%, while the net electricity falls from 3977 kW to 3506 kW. Interestingly, the TUCP has a minimum value at the evaporator temperature of 273 K and condenser 2 temperature of 322.3 K. The optimization results indicate the values of the produced hydrogen rate and net electricity with 5.85 kg/h and 4187 kW are more than those of the base case. Also, the optimal values are 7.046 $/GJ, 36.82%, and 65.42% for the TUCP and energy and exergy efficiencies, respectively.Book Part Citation - Scopus: 11Thermodynamic Performance Evaluation of a Geothermal Drying System(Springer Verlag, 2014) Helvacı, Hüseyin Utku; Gökçen Akkurt, Gülden; Helvacı, Hüseyin Utku; Gökçen Akkurt, Gülden; 01. Izmir Institute of Technology; 03.06. Department of Energy Systems Engineering; 03. Faculty of EngineeringRenewable energy sources such as geothermal energy can be used in drying processes as a heat source due to the high energy costs of fossil fuels. In this study, geothermal cabinet type dryer was constructed and situated in Balcova-Narlidere Geothermal Field, Turkey where the clean city water of district heating system is used as an energy source for the dryer. The dryer was tested on site for drying of olive leaves and energy and exergy analyses of the drying process conducted under two cases: Case 1. Exhaust air was rejected to the environment. Case 2. A portion of exhaust air was re-circulated. Energy Utilization Ratio (EUR) was determined as 7.96 for Case 1 and 50.36 for Case 2. The highest rate of exergy destruction occurred in the fan, followed by heat exchanger and the dryer, accounting for 0.2913, 0.05663 and 0.0115 kW, respectively. Exergetic efficiency of the drying chamber was calculated as 89.66 %. Re-circulating the exhaust air decreased the exergy value at the outlet of the dryer from 0.1013 to 0.08104 kW, indicating that re-using the air increases the performance of the dyer.Article Citation - WoS: 25Citation - Scopus: 32District Heating System Design for a University Campus(Elsevier Ltd., 2006) Yıldırım, Nurdan; Toksoy, Macit; Toksoy, Macit; Yıldırım, Nurdan; Gökçen Akkurt, Gülden; 03.10. Department of Mechanical Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technologyİzmir Institute of Technology campus is in use since 2000 and still under development. At present, heating is provided by individual fuel boilers. On the other hand, the campus has a geothermal resource in its borders with a temperature of 33 °C. Because of this low geothermal fluid temperature; heat pump district heating system is considered for the campus. As an alternative, fuel boiler district heating system is studied. Each heating system is simulated using hourly outdoor temperature data. For the simulations, a control system with constant flow rate and variable return water temperature is used and the main control parameter is the indoor temperature. Various heating regime alternatives have been studied for heat pump district heating system for the various condenser outlet temperature and geothermal fluid flow rate, and two of these alternatives are given in this study. Furthermore, economic analysis has also been done for each heating system alternative based on investment and operational costs. Results indicate that heat pump district heating system has the highest investment but lowest operational cost. The alternatives are evaluated according to internal rate of return method, which shows the profit of the investment and resulted that, the heat pump district heating system has minimum 3.02% profit comparing with the fuel boiler district heating system at the end of the 20-year period.Article Citation - WoS: 30Citation - Scopus: 36Overview of Kizildere Geothermal Power Plant in Turkey(Elsevier Ltd., 2004) Gökçen Akkurt, Gülden; Gökçen Akkurt, Gülden; Hepbaşlı, Arif; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyAchieving sustainable development is a target that is now widely seen as important in worldwide public opinion. In this context, the utilization of renewable energy resources such as solar, geothermal and wind energy appears to be one of the most efficient and effective ways of achieving this target. Recently, power generation from geothermal energy has become of big importance in Turkey, which is located on the Mediterranean sector of the Alpine-Himalayan Tectonic Belt and is among the first seven countries in abundance of geothermal resources around the world. The main objective in doing the present study is twofold, namely: (a) to investigate Turkey's geothermal energy potential for power generation and (b) to overview the Denizli-Kizildere geothermal power plant (DKGPP) with an installed capacity of 20.4 MWe, which is at present the only operating geothermal power plant of Turkey. Based on the drilling data, which have been gathered to date, Turkey's geothermal energy potential for power generation is determined to be 764.81 MWe. Electricity generation projections of Turkey are also 500 MWe from Germencik, Kizildere, Tuzla and several of the other fields by the year 2010 and 1000 MWe by 2020. The Denizli-Kizildere geothermal field has an estimated capacity of 200 MWe. The DKGPP was put into operation in 1984 and has been operated since then. It produced an electrical energy of 89,597 MWh in 2001, representing an electric power of 10.6 MWe in the same year. Present applications have shown that in Turkey, geothermal energy is a promising alternative and can make a significant contribution towards reducing the emission of greenhouse gases. As the public recognizes the projects, the progress will continue.Article Citation - WoS: 15Citation - Scopus: 16Geothermal Fields Suitable for Power Generation(Taylor and Francis Ltd., 2004) Gökçen Akkurt, Gülden; Gökçen Akkurt, Gülden; Hepbaşlı, Arif; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyTurkey is located on the Mediterranean sector of Alpine-Himalayan Tectonic Belt with many grabens, acidic volcanism, hydrothermal alteration zones, numerous hot springs and fumaroles. The data gathered since 1962 indicate that Turkey has a high geothermal energy potential. By comparison, it is among the first seven countries in abundance of geothermal resources around the world, while the share of its potential used is only about 2%. This means that considerable studies on geothermal energy could be conducted in order to increase energy supply and to reduce atmospheric pollution in Turkey. The main objective of the present study is threefold, namely: (1) to overview Turkey's geothermal fields suitable for power generation together with their possible utilization opportunities, (2) to present problems encountered and research projects developed in the Denizli-Kizildere geothermal field with an estimated capacity of 200 MWe and (3) to assess the current status of geothermal energy use for electric energy production in Turkey. The Denizli-Kizildere geothermal power plant with an installed capacity of 20.4 MWe which is, at present, the only operating geothermal power plant of Turkey, was put into operation in 1984, while electricity from geothermal energy has been produced commercially since 1913. This plant produced on average an electrical energy of 84,920 MWh in the period between 1998-2001, representing an average electric power of 10.45 MWe in the same period. Parallel to the development of the geothermal energy utilization in the country, it is projected that, by the years 2010 and 2020, the total geothermal power installed capacity will increase to 500 MWe, respectively.