54 Int. J. Exergy, Vol. 12, No. 1, 2013 Copyright © 2013 Inderscience Enterprises Ltd. Exergy analysis of geothermal electricity using the Kalina cycle Christopher Koroneos* and Dimitrios Rovas Laboratory of Heat Transfer and Environmental Engineering, Aristotle University of Thessaloniki, P.O. Box: 483, GR. 54124, Thessaloniki, Greece Email: koroneos@aix.meng.auth.gr Email: drovas@aix.meng.auth.gr *Corresponding author Abstract: The geothermal energy that is stored in the earth is so vast that could supply all the energy needed by humanity. The difficulty in tapping this energy lies in its diffusivity. The geothermal energy in regions near volcanoes is close to the surface and easy to use economically. In this paper a vapour dominated system will be examined. The electricity that is produced from such a system is economically and environmentally in a better position than the electricity produced from coal or diesel. The Kalina cycle will be used in this system and an exergy analysis is performed. The Kalina cycle is a new concept in power generation and uses a mixture of 70% ammonia and 30% water as the working fluid with the potential to increase the exergy efficiency over the Rankine cycle. The exergy analysis will provide a qualitative and quantitative picture of the process. Keywords: exergy analysis; geothermal energy; Kalina cycle; electricity production; desalination. Reference to this paper should be made as follows: Koroneos, C. and Rovas, D. (2013) ‘Exergy analysis of geothermal electricity using the Kalina cycle’, Int. J. Exergy, Vol. 12, No. 1, pp.54–69. Biographical notes: Christopher Koroneos is a chemical engineer. He did all his studies at the Department of Chemical Engineering of Columbia University in New York, USA, where he later was a Professor. Now he is at Laboratory of Heat Transfer and Environmental Engineering of Aristotle University of Thessaloniki and at the Unit of Environmental Science and Technology of the Department of Chemical Engineering at the National Technical University of Athens. He is teaching at the Interdisciplinary Programme of Post Graduate Studies ‘Environment & Development’ of the National Technical University of Athens and at the Hellenic Open University. His research interests are in Renewable Energy, Exergy Analysis, Life Cycle Assessment and Sustainable Development. Dimitrios Rovas is a research associate at the Laboratory of Heat Transfer and Environmental Engineering since 2005. He received his Mechanical Engineer Diploma in 2003 at the Faculty of Engineering of Aristotle University of Thessaloniki. His fields of interest are renewable energy, exergy analysis, life cycle assessment and sustainable development.