Performance enhancement of a spherical solar distiller using yttrium oxide (Y2O3) nanoparticles and solar reflectors

• Integration of Y₂O₃-activated carbon nanoparticles and solar reflectors enhanced SSD productivity by 54.89%, reaching 6.97 L/m²/day. • Energy and exergy efficiencies significantly improved, reaching 82.83% and 4.9% respectively, with a 114.73% increase in the Exergy Production Factor (EPF). • The optimized SSD3NR design reduced the economic payback period from 31 to 23 days, confirming its cost-effectiveness for decentralized water production Water scarcity in arid and remote regions demands decentralized, low-cost desalination solutions. This study investigates the performance enhancement of a spherical solar distiller (SSD) through the integration of yttrium oxide (Y₂O₃) nanoparticles and external solar reflectors. Three configurations were experimentally evaluated: the baseline SSD, a nanoparticle-modified still (SSD3N), and a dual-modified system with nanoparticles and reflectors (SSD3NR). The dual-modified SSD3NR achieved a daily freshwater yield of 6.97 L/m²/day, representing a 54.9% improvement over the baseline (4.50 L/m²/day). Energy efficiency increased from 42.9% to 82.8%, exergy efficiency nearly doubled from 2.5% to 4.9%, and the exergy production factor improved by 114.7%. The payback period was shortened from 31 to 23 days, confirming economic viability. The novelty of this work lies in the first experimental demonstration of a dual-modified spherical distiller combining nanofluid-based thermal enhancement with reflector-based optical flux concentration, a configuration not previously reported in the literature. This approach provides a scalable and sustainable pathway for freshwater production in off-grid and water-stressed regions.