Int. Journal of Renewable Energy Development 5 (2) 2016: 129-138 Page | 129 © IJRED – ISSN: 2252-4940, July 15 th 2016, All rights reserved Contents list available at IJRED website Int. Journal of Renewable Energy Development (IJRED) Journal homepage: http://ejournal.undip.ac.id/index.php/ijred Energetic and Exergetic Improvement of Geothermal Single Flash Cycle Navid Nazari a* and Soheil Porkhial a a Faculty of science, Islamic Azad University, Karaj, Iran ABSTRACT: This paper presents a method for modification of single flash cycle power output. The thermodynamic process of the new method consists of extracting a fraction of hot wellhead geothermal fluid for the purpose of superheating saturated steam entering the turbine. Computer programming scripts were developed and optimized based on mathematical proposed models for the different components of the systems. The operating parameters such as separator temperature, fluid wellhead enthalpy and geothermal source temperature are varied to investigate their effects on both net power output and turbine exhaust quality of the systems. Also, full exergy assessment was performed for the new design. The results of separator temperature optimization revealed that specific net power output of the new design can be boosted up to 8% and turbine exhaust quality can be diminished up to 50% as compared to common single flash cycle. In addition, for wells with higher discharge enthalpy, superheating process improve specific net power output even up to 10%. Finally, it was observed that the overall system exergy efficiency was approximately raised 3%. Keywords: Super heater, geothermal energy, single flash cycle, exergy analysis,optimization Article History: Received January 5 th 2016; Received in revised form June 25 th 2016; Accepted July 3 rd 2016; Available online How to Cite This Article: Nazari, N. and Porkhial, S. (2016). Energetic and Exergetic Improvement of Geothermal Single Flash Cycle. Int. Journal of Renewable Energy Development, 5(2),129-138. http://dx.doi.org/10.14710/ijred.5.2.129-138 * Corresponding Author: +98-44320033; mobile: +98-912 2636 817 Email: nazari.nvd@gmail.com 1. Introduction Development of human societies are dependent on energy availability, hence, it is vital to find reliable and stable source of global energy demand in future (Dincer 2007). Today, about 86% of the world's energy production is provided from combustion of fossil fuels like oil, gas and coal. Also, it is predicted that these resources will be the main source of energy production even for future decades (Abas et al. 2015). In respect to limited characteristic of these resources and recent global concerns about climate changes, which resulted from emission of green house gases, substitution of fossil base resources with clean and renewable ones is becoming favorable (Dincer et al. 2012). Geothermal energy is a clean and reliable source of energy, which can be used either for electricity generation or direct utilization (Phillips 2010). As it is reported, less than 0.5% of total worldwide installed electrical capacity was generated using geothermal sources in 2010, but it is predicted that the advancement of exploitation technologies will significantly increase this potential in the future (Chamorro et al. 2012). From the very first use of geothermal energy for electricity generation to date many developments in geothermal power technologies have been applied (DiPippo 2015). However, technologies which were utilized to generate electricity from geothermal resource can be categorized based on three main conversion cycles: dry steam plants operate by high temperature geothermal steam coming from steam- dominated resources, flash plants use moderate to high temperature geothermal fluid discharged from liquid- dominated resources and binary plants which are best suited for power production from low temperature resources (Coskun et al. 2011). Among available