An innovative S–CO2 recompression Brayton system and its thermodynamic, exergoeconomic and multi-objective analyses for a nuclear spacecraft

Abstract

An innovative layout of a recompression supercritical carbon dioxide (S–CO2) cycle for nuclear spacecraft was proposed in this work. Thermodynamic and exergoeconomic analysis of the innovative cycle have been performed to study the effect of essential operating parameters on the split ratio, maximum operating pressure ratio, minimum operating temperature, maximum operating temperature, and compressor C4 inlet pressure based on the first and second laws of exergoeconomics and efficiency. Finally, the innovative power cycle is optimized with high efficiencies, low cost and lightweight. The results show that the optimization progress is based on the thermodynamic and exergoeconomics method; the minimum operating temperature can significantly improve efficiencies and reduce circular investment cost; then after the multi-objective optimization progress, the thermal efficiency (ηth), exergy efficiency (ηex) and mass of Brayton turbomachinery unit (MBTU) improved by 2.71 %, 3.69 %, and 2.8 %; total capital cost rate (total) and levelized cost of electricity (LCOE) reduced by 0.88 % and 4.55 %, respectively.

Keywords

• S-CO2 recompression Brayton cycle
• Thermal efficiency
• Sensitivity analysis
• Multi-objective optimization
• Improved cycle performance