Thermal and Exergy Efficiency Analysis of a Solar-driven Closed Brayton Power Plant with Helium & s-CO2 as Working Fluids

Solar Thermal Energy power plants operating with traditional steam Rankine cycles have a low thermal and exergy efficiency. An attractive pathway to increase the competitiveness of this technology is to investigate Closed Brayton cycles working with different fluids with desirable properties that show potential for improving their efficiency In this work a solar driven regenerative Brayton cycle is studied employing two different working fluids: Helium and supercritical CO2. The cycle efficiencies are determined for different turbine inlet temperatures and for the optimal compressor pressure ratios. Additionally, an exergy analysis breakdown of the different plant components is shown for each case, while the solar field sizes and working fluid flows are calculated for a fixed gas turbine output