Thermo-Economic Analysis for the Feasibility Study of a Binary Geothermal Power Plant in India

Abstract

AbstractThe objectives of ORC thermodynamic analysis are maximum performance and thermal conversion efficiency. For a feasibility design study, it is important to optimize both energy performance and system cost. Based on typical geothermal resources, this article describes a feasibility study for a binary geothermal plant in India. For important cycle design alternatives, a variety of working fluids, and component selection factors, thermodynamic and economic evaluations were done. The target function for selecting the most thermo-economic designs is calculated by dividing total Purchased Equipment Costs (PEC) by net electrical power output (Wnet). The working fluids investigated are n-pentane, R245fa, and R134a. The thermodynamic analysis shows that at a given turbine inlet pressure and mass flow rate of the working fluid, the net electrical power output (Wnet) of the cycle design reaches its maximum. Two-stage designs outperform one-stage designs in terms of Wnet, thermal, and exergy efficiency. According to an economic comparison, working fluid types and cycle designs have a significant impact on economic performance as assessed by PEC. The top five options were subjected to profitability analysis. The results show that a normal Rankine cycle with a two-stage turbine employing n-pentane is the most thermo-economical design based on the brine resource and reinjection conditions.KeywordsOrganic Rankine cycleThermodynamic cycle designBinary geothermal power plantFeasibility study