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 phi/kWh and 0.67-5.27 years, respectively, with an annual full-load hour ranging from 5000 to 8500. (C) 2018 Elsevier Ltd. All rights reserved.