Thermoeconomic Analysis of Subcritical and Supercritical Isobutane Cycles for Geothermal Power Generation

This article presents a novel and comprehensive approach for the thermoeconomic evaluation of subcritical supercritical isobutane cycles geothermal temperatures Tgeo = 100–200 °C. The are optimized with respect to maximum net power or minimum levelized cost electricity (LCOE). Cycle optimization is also included, using superheat temperature avoid turbine erosion, which usually neglected in literature. results show that economic optimums found far superheated region, while thermal obtained dry saturated slightly vapor at inlet (ΔTsup < 5 °C). Supercritical achieve better performance than 179–200 Internal heat recuperation improves cycle performance: output increases LCOE decreases, but specific installation costs (SICs) increase due additional exchanger. For 120 → 150 °C, 100 80 USD2022/MWh SIC 7000 5250 USD2022/kW, 200 estimated 70 4600 USD2022/kW.