Proposal and assessment of a novel supercritical CO₂ Brayton cycle integrated with LiBr absorption chiller for concentrated solar power applications

A novel recompression supercritical CO₂ Brayton cycle integrated with an absorption chiller (RSBC/AC) is proposed for air-cooled concentrated solar power (CSP) plants. The residual heat of CO₂ in the cold end of the supercritical CO₂ cycle is utilized to drive the absorption chiller, which chills the CO₂ exiting the precooler further before it enters the main compressor. Parametric analyses and optimizations are performed for the RSBC/AC. Energy and exergy analyses and comparisons are conducted to illustrate the mechanisms of RSBC/AC performance improvement. Sensitivity analyses of pressure drop and ambient temperature are performed to investigate RSBC/AC performance under various working conditions. Economic evaluations of a CSP plant integrated with RSBC/AC are performed to investigate its feasibility as an alternative to the stand-alone supercritical CO₂ cycle. Results show that the optimized thermal and exergy efficiencies of RSBC/AC are 5.19% and 6.12% higher, respectively, than those of the stand-alone supercritical CO₂ cycle. The exergy destruction/loss in the high-temperature recuperator and precooler of RSBC/AC are significantly reduced. The levelized cost of electricity and payback period for the plant integrated with RSBC/AC are reduced by 0.46–0.77 ￠/kWh and 0.67–5.27 years, respectively, with an annual full-load hour ranging from 5000 to 8500.