Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
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Article Citation - WoS: 40Citation - Scopus: 47Boron in Geothermal Energy: Sources, Environmental Impacts, and Management in Geothermal Fluid(Elsevier, 2022) Mott, A.; Baba, Alper; Hadi Mosleh, Mojgan; Ökten, Hatice Eser; Babaei, Masoud; Gören, Ayşegül Yağmur; Feng, C.; Recepoğlu, Yaşar Kemal; Uzelli, Taygun; Uytun, Hüseyin; Morata, Diego; Yüksel Özşen, AslıThe problem of hazardous chemicals in geothermal fluid is a critical environmental concern in geothermal energy developments. Boron is among the hazardous contaminants reported to be present at high concentrations in geothermal fluids in various countries. Poor management and inadequate treatment of geothermal fluids can release excessive boron to the environment that has toxic effects on plants, humans, and animals. Despite the importance of boron management in geothermal fluid, limited and fragmented resources exist that provide a comprehensive understanding of its sources, transport and fate, and the treatment strategies in geothermal energy context. This paper presents the first critical review from a systematic and comprehensive review on different aspects of boron in geothermal fluid including its generation, sources, toxicity, ranges and the management approaches and treatment technologies. Our research highlights the origin of boron in geothermal water to be mainly from historical water-rock interactions and magmatic intrusion. Excessive concentrations of boron in geothermal fluids have been reported (over 500 mg/L in some case studies). Our review indicated that possible boron contamination in geothermal sites are mostly due to flawed construction of production/re-injection wells and uncontrolled discharge of geothermal water to surface water. The dominancy of non-ionic H3BO3 species makes the selection of the suitable treatment method for geothermal waters limited. Combining boron selective resins and membrane technologies, hybrid systems have provided effluents suitable for irrigation. However, their high energy consumption and course structure of boron selective resins encourage further research to develop cost-effective and environmentally friendly alternatives.Article Citation - WoS: 8Citation - Scopus: 11Geothermal Potential of Granites: Case Study- Kaymaz and Sivrihisar (eskisehir Region) Western Anatolia(Elsevier, 2022) Chandrasekharam, Dornadula; Baba, Alper; Ayzit, Tolga; Singh, Hemant K.Radiogenic granites are gaining importance due to their ability to generate a substantial amount of electricity and support the advancement of agricultural and water sectors. In the western Anatolian region, such granites occupy a cumulative area of 6910 km2 varying from 7 to 20 μW/m3, far above the heat generated by the average continental crust of 5 μW/ m3. One cubic. The granite plutons of the Eskisehir region are amongst such granites with radioactive heat generation kilometer of such granite can generate 79 × 106 kWh of electricity. In the present case, the Eskisehir granites are capable of generating 616 million kWh of carbon-free electricity. Besides electricity, the heat from the granites can be utilized for space heating and greenhouse cultivation. This energy can also be utilized for the generation of fresh water from the sea through the desalination process. Hydrofracturing of the granites to create a fracture network connecting injection and production well is being replaced with closed-loop system that do not require knowledge about the stress pattern of the region and reduce the risk of induced micro-seismicity that was a bottleneck for developing EGS projects. Although the currently estimated cost of electricity generated from EGS projects is 9 euro cents/kWh, this cost will get reduced due to technological development in drilling technology. The Western Anatolian region has an additional advantage over the cost, since the drilling depth to capture the heat from the granites is shallow (∼3 km) which gives further benefit to the cost due to the reduction in drilling depth cost. In addition to high radiogenic granites, the presence of curie point temperature at shallow depth, high heat flow, and high geothermal gradient makes this region a warehouse of energy making Turkey energy-food and water independent in the future.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; Khani, Leyla; Mohammadpourfard, Mousa; Gökçen Akkurt, GüldenEmploying 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.Conference Object Citation - Scopus: 2Importance of Load Based Automatic Control in Geothermal Energy Systems(Elsevier, 2003) Şener, Adil Caner; Toksoy, Macit; Aksoy, NiyaziGeothermal energy production is not possible without use of electricity, since electricity is needed to pump geothermal fluid from underground to consumption point. The biggest portion of the operating cost in geothermal district heating systems comes from pumping energy consumption. In ibis study Balcova-Narhdere geothermal district heating system has been analysed and the optimum control strategies minimising the energy consumption in the system discussed. Then decisive factors in the efficient control and operation of geothermal healing systems have been studied. Finally fundamental automation requirements for efficient operation of geothermal district heating systems has been introduced. Copyright © 2003 IFAC.Article Citation - WoS: 33Citation - Scopus: 42Thermodynamic Assessment of Downhole Heat Exchangers for Geothermal Power Generation(Elsevier, 2019) Yıldırım, Nurdan; Parmanto, Slamet; Akkurt, Gülden GökçenDownhole heat exchanger is a device to extract heat from geothermal fluid. While it is widely used for heating purposes, its use for power generation has not been reported. The aim of this study is to examine the feasibility of power generation from a 2500 m deep existing geothermal well with high temperature gradient and insufficient flowrate by using a downhole heat exchanger. For this purpose, a thermodynamic and an economic evaluation model are developed by the use of Engineering Equation Solver software. Additionally, the parametric studies have been carried out to identify the effects of insulation, geothermal well conditions, geometry of downhole heat exchanger, mass flowrate and type of working fluids on the performance of downhole heat exchanger system. Consequently, work output of the best alternative is computed as 2511 kW(e) with 64 kg/s mass flowrate of R-134a for 2500 m-deep downhole heat exchanger having inner pipe diameter of 0.127 m. Electricity generation cost and simple payback time are calculated as 46 $/MWh and 2.25 years, respectively. The obtained results showed that the downhole heat exchanger system can be a feasible alternative for wells with very low geothermal flowrate to generate power. (C) 2019 Elsevier Ltd. All rights reserved.