Advanced exergy analysis and performance enhancement of air-cooled solar recompression supercritical carbon dioxide systems

Abstract

This study advances the efficiency of a recompression power generation cycle using supercritical carbon dioxide, leveraging solar energy as a sustainable alternative to fossil fuels. It is the first to uniquely address the performance of air-cooled solar recompression cycles by evaluating both the heat and cooling source. Traditional water and cooling towers are replaced with air and fans to conserve water and enhance cooling efficiency. The study employs advanced exergy analysis to identify optimization strategies and reduce exergy destruction. The baseline system “System A” identifies the precooler and main compressor as key areas for improvement. Two novel systems are proposed: “System B,” which integrates an intercooler and a secondary compressor to significantly cut exergy losses, and “System C,” which uses a single-effect absorption refrigeration cycle to further reduce exergy destruction. The results show an increase in energy efficiency and exergy efficiency from 23.24% in System A to 25.72% in System B and 24.28% in System C. Advanced exergy analysis reveals that, although the central receiver and high-temperature recuperator are major sources of exergy destruction, the heliostat and low-temperature recuperator are crucial for system optimization. This study's unique approach combines comprehensive exergy analysis with innovative system proposals based on the results.