Exergetic Performance Investigation of Varying Flashing From Single to Quadruple for Geothermal Power Plants

Abstract

Geothermal power plants are considered important renewable energy resources for clean energy production. Flash steam type plants constitute a significant portion of worldwide geothermal power. In this study, single, double, triple, and quadruple flash steam geothermal power plants are investigated with reinjection options. The optimal operating points are determined specifically through optimal flashing pressures. The turbine power outputs, energy efficiencies, and exergy efficiencies are further studied. A rise in the flashing stages from single to double is found to increase the power outputs considerably. However, when the flashing stages are increased from double to triple and triple to quadruple, the increase in turbine power outputs is found to drop significantly. Also, both exergy efficiency and energy efficiency are found to reduce with increasing number of flash stages. The energy efficiencies are obtained as 28%, 25.5%, 24.2%, and 23.5% for single, double, triple, and quadruple plants, respectively. Furthermore, the exergy efficiencies are found to be 72.6%, 70.9%, 70.2%, and 69.8% for these plants, respectively.