Exergo-Environmental Analysis of a Supercritical Hybrid Brayton–ORC Cycle System Using Solar Radiation and Biomass as Energy Source

The increasing cooling demand in residential sectors located in warm climates requires sustainable energy systems capable of supplying thermal loads with reduced environmental impact. This study presents an exergo-environmental assessment of a hybrid system based on a supercritical Brayton cycle coupled with an organic Rankine cycle (ORC). Solar radiation and biomass are used as energy sources to supply the cooling demand of a residential complex composed of 275 housing units constructed with Glass Mat fiberglass. The system was evaluated through exergy analysis to identify the main sources of irreversibility and life cycle assessment (LCA) to quantify environmental impacts during construction, operation, maintenance, and decommissioning stages. The exergetic results show that the solar field represents the largest source of irreversibility, accounting for 49.17% of the total, while the heater and evaporator are the components with the greatest improvement potential in the Brayton and ORC cycles, respectively. The exergo-environmental analysis indicates that the compressor in the Brayton cycle presents the highest environmental impact associated with exergy destruction (BD = 76.16 mPts/h, Bk = 77.65 mPts/h), while the ORC pump shows the highest impact in the ORC cycle (BD = 60.57 mPts/h, Bk = 60.58 mPts/h). Turbines exhibit the highest exergo-environmental fractions (16.70%, 16.41%, and 12.11%), which are mainly associated with their manufacturing stage.