Design and Optimization of the Kalina Cycle for Geothermal Energy in Kenya

Abstract

The Great Rift Valley, an area of Eastern Africa with strong tectonic activity, offers immense potential for large-scale geothermal projects. The geothermal energy is also considered clean and renewable, so this paper presents the exploitation of geothermal energy with Kalina cycle in Kenya. The software Engineering Equation Solver (EES) is used to run the models for each operating condition, using the thermodynamic properties data of ammonia and water supplied with that software package. Based on the good agreements with the actual operating parameters, the thermodynamics analysis of Kalina geothermal power cycle was analyzed. The optimum of the system is influenced by the condensation temperature, ammonia mass fraction, turbine inlet pressure and the temperature of heat source. The cycle efficiency and the electricity generation for the Kalina cycle are illustrated with different conditions. The ammonia content and the pressure of turbine is needed to be less than the optimum point. The largest cycle efficiency is found 20%, but the pressure is so high that the cost of components should be considered. Thermodynamic analysis of an operational 1 MWe binary geothermal power plant in Kenya is performed. Through energy and exergy, the energy efficiency is about 6.9% and the largest exergy destruction occurs at the condenser. The utilization of the low-temperature energy will increase efficiency and reduce the consumption of the fossil fuels.