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Exergy analysis of electricity generation for the geothermal resources using organic rankine cycle: Kızıldere-denizli case

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Geothermal energy is counted as one of the most significant renewable energy sources and currently in use for electric generation at many locations around the world. Turkey enjoys being seventh place in the world for geothermal resources and fifth place in direct use as the space and district heating. Geothermal resources are mainly located in western region in Turkey and there exists only one 20.4 MWe flash steam type power plant located at Kızıldere, Denizli. Since more Geothermal power plants are to be built under the cover of renewable energy incentives, efficient, and feasible technologies need to be investigated. As such, the purpose of this study is to demonstrate that Organic Rankine Cycle can be more efficient for the electric energy generation compared with the flash steam power plant currently in use at Kızıldere. Exergy analysis has been proven to be a powerful tool for evaluating thermodynamic efficiencies and losses for the thermal processes. Furthermore, exergy analysis provides a proper tool for optimum operation and design of complex thermal systems such as geothermal power plant. In this study, for the efficiency measure, the exergy analysis of the Organic Rankine Cycle is performed with four different working fluids. Exergy losses are calculated for each component of the Organic Rankine Cycle and the results are presented in tables. Isobutene, among others, has been found as the most efficient functioning fluid for the power plant in concern. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 830–836, 2013