4E Comparative Analysis of Two sCO2 Brayton/ORC Hybrid Configurations for Cooling Loads in Residential Applications Using Solar Radiation and African Palm Biomass

This study evaluates, from energy, exergy, exergo-sustainability, and environmental perspectives, two combined-cycle configurations based on a supercritical CO2 Brayton cycle coupled to an ORC: a simple reheat configuration (S-CO2-ORC) and a recompression-reheat configuration (SRC-CO2-ORC). Both were assessed under two thermal sources: concentrated solar power (CSP) and a hybrid biomass-CSP source using oil palm residues. Sizing was based on the cooling demand of a 130-home residential complex in Barranquilla, estimated at 152 kW through hourly simulation. The SRC-CO2-ORC configuration delivered the best energy performance, reaching 138.38 kW and 55.34% with CSP and up to 157.28 kW and 57.66% under hybrid operation. The highest irreversibilities were concentrated in the solar field and receiver, while the thermal sources contributed more than 85% of the total carbon footprint. The lowest life-cycle impact corresponded to the SRC-CO2-ORC-Solar configuration, at 0.0117 kg CO2-eq/kWh, against 0.0194 kg CO2-eq/kWh for the S-CO2-ORC-Hybrid case. The results confirm the technical feasibility of these configurations for residential applications and reveal a clear trade-off between thermodynamic performance and minimum carbon footprint.