Mechanical Engineering / Makina Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4129
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Conference Object Citation - WoS: 7Modeling of Low Temperature Geothermal District Heating Systems(Taylor and Francis Ltd., 2004) Yıldırım, Nurdan; Gökçen Akkurt, Gülden; Gökçen, Gülden; Yıldırım, Nurdan; 03.10. Department of Mechanical Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this work, low temperature geothermal district heating systems with heat pumps have been studied and compared with fuel-oil boiler heating systems for intermittent and continuous regimes according to the optimum indoor air temperature and operational cost. Izmir Institute of Technology (IZTECH) Campus is taken as a case study. Various heat pump and boiler configurations are studied to meet required duty. Operational cost analysis for each alternative is conducted. According to the results, for IZTECH Campus the best alternative, which gives the optimum indoor air temperature and the lowest operational cost, is heat pump continuous regime.Book Part Citation - Scopus: 3Performance Analysis of Single-Flash Geothermal Power Plants: Gas Removal Systems Point of View(Nova Science Publishers, Inc., 2012) Yıldırım Özcan, Nurdan; Gökçen, Gülden; Gökçen Akkurt, Gülden; Yıldırım, Nurdan; 03.10. Department of Mechanical Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyNon-condensable gases (NCGs), natural components of geothermal fluids, affect the performance of a geothermal power plant (GPP) significantly. Therefore, the NCGs should be removed from the process to optimise the thermodynamic efficiency of the plant. GPPs require large capacity NCG removal systems that occupy large portion in the total plant cost and auxiliary power consumption. The flashed-steam GPPs, which are commonly used in the World, are a relatively simple way to convert geothermal energy into electricity when the geothermal wells produce a mixture of steam and liquid. The primary aim of this study is to develop a code for simulating flashed-steam GPPs to examine the thermodynamic performance of NCG removal systems, which represent major concerns at planning and basic design stages of GPPs. A single-flash GPP model is developed and simulated to identify the effects of input variables, such as NCG fraction, separator pressure and condenser pressure. Among the variables, NCG fraction is the most significant parameter affecting thermodynamic performance of single-flash GPPs. The net power output and overall exergetic efficiency of single-flash GPP are decreased 0.4% for compressor system (CS), 2.2% for hybrid system (HS), 2.5% for reboiler system (RS), and 2.7% for steam jet ejector system (SJES) by 1% increase in NCG fraction.Article Citation - Scopus: 10Exergy Analysis and Performance Evaluation of Kizildere Geothermal Power Plant, Turkey(Inderscience Enterprises Ltd., 2004) Yıldırım, Eda Didem; Gökçen Akkurt, Gülden; Gökçen Akkurt, Gülden; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyConventional geothermal power plants (GPP) differ from fossil-fuel power plants (FFPP) in many ways. The most specific ones are GPPs, are not cyclic plants and the working fluid is not pure steam. Geothermal steam contains non-condensable gases (NCG) which degrade power plant efficiency. This discrepancy leads to two considerations in energy and exergy analysis of GPPs. One is that the amount of NCGs in the steam cannot be omitted during the calculations; the other is that the dead state composition varies throughout the process. In this work, energy and exergy analysis is conducted to assess the performance of Kizildere GPP under both considerations. The net second law efficiencies of the plant based on reservoir and wellhead exergy are 24.3 and 27.2% respectively. Both indicate that the plant performance is low comparing with the other single-flash GPPs and FFPPs. The losses are mainly associated with high NCG content and low steam fraction of the fluid.Article Citation - WoS: 66Citation - Scopus: 79Piping Network Design of Geothermal District Heating Systems: Case Study for a University Campus(Elsevier Ltd., 2010) Yıldırım, Nurdan; Toksoy, Macit; Yıldırım, Nurdan; Toksoy, Macit; Gökçen Akkurt, Gülden; 03.10. Department of Mechanical Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyGeothermal district heating system design consists of two parts: heating system and piping network design. District heating system design and a case study for a university campus is given in Yildirim et al. [1] in detail. In this study, piping network design optimisation is evaluated based on heat centre location depending upon the cost and common design parameters of piping networks which are pipe materials, target pressure loss (TPL) per unit length of pipes and installation type. Then a case study for the same campus is presented. © 2010 Elsevier Ltd.