Solar rankine and absorption multi-generation for residential buildings: design, exergy analysis and techno-economic optimization across hemispheric climates

• Solar trigeneration system tested across hemispheric climates. • Computer models are combined for full system design and energy use optimization. • System reached 19.42 % exergy efficiency with consistent surplus energy output. • Annual CO 2 emissions were reduced by 332.43 tons under optimal conditions. • Framework supports scalable zero-energy housing applications. Seasonal contrasts between hemispheres pose major challenges to solar energy availability and demand management, yet no previous solar-thermal multi-generation study has systematically evaluated system robustness across mirrored latitudes with opposite seasonal patterns. This study presents a solar thermal multi-generation framework designed to ensure reliable, year-round performance across contrasting hemispheric climates. The proposed system integrates a heliostat field, central receiver, molten-salt thermal storage, a Solar Rankine cycle for power generation, a recuperator for domestic hot water and space heating, and an absorption chiller for cooling. Four representative cities, Sydney and Melbourne (Australia), and Ahvaz and Isfahan (Iran), were selected for their roughly similar latitudes, contrasting climates, and reliable meteorological data, enabling a consistent hemispheric comparison of system adaptability. The methodology combined Building Energy Optimization (BEopt) simulations, thermodynamic modeling in Engineering Equation Solver (EES), and multi-objective optimization using Response Surface Methodology (RSM). Under optimal operation, the system achieved an exergy efficiency of 19.42% producing 1,629.6 MWh of electricity, 10,527.8 MWh of heating, and 1,446.8 MWh of cooling annually in Isfahan. Carbon Dioxide (CO 2 ) emissions decreased by 332.43 tons per year relative to baseline, and the cost rate was optimized to $169.93/h. The results confirm that the framework maintains stable performance under seasonal reversals, an aspect rarely quantified in solar thermal multi-generation research. The study introduces two key novelties: a hemispheric robustness evaluation framework and a transferable methodology that links building-level demand modeling with thermodynamic simulation and optimization, offering a scalable pathway toward climate-responsive, zero-energy residential systems.