Enhancing solar distillation and fruit drying efficiency with parabolic concentrators and phase change material: A sustainable dual-purpose approach

• Dual-purpose solar system for water distillation and food drying. • 222.25% increase in daily water yield using parabolic concentrators and PCM . • Cost of distilled water was reduced to $0.0098/L, improving economic feasibility . • Integration of PCM ensures sustained operation with low solar radiation. • Synergistic use of PCM and parabolic concentrators enhances efficiency. As global water scarcity and food preservation challenges intensify due to population growth, efficient and sustainable solutions are essential. This study aims to develop an innovative solar distillation and drying system that integrates parabolic concentrators and phase change materials (PCM), specifically a graphite matrix, to enhance water production and food drying efficiency. The experimental study was conducted in Nanjing, China, using a corrugated absorber within a solar parabolic concentrator. The system demonstrated a significant improvement in water productivity, achieving 12.58 kg/m 2 of water per day, compared to 3.898 kg/m 2 from a conventional flat plate solar distiller, representing a 222.25 % increase in productivity, along with 39.9 % thermal efficiency and 6.31 % exergy efficiency. In grape drying experiments, the system effectively reduced the moisture content from 80 % (wet basis) to approximately 20 %, with an average convective heat transfer coefficient of 6.8 W/m 2 °C. The absorber plate temperature peaked at 70.8 °C , demonstrating an effective enhancement in the drying process. Moreover, the integration of PCM allowed energy storage, enabling continuous operation during cloudy periods or at night, which is particularly beneficial for arid regions with limited water resources. These findings confirm that combining parabolic concentrators and PCM provides a scalable dual-purpose solution for improving solar distillation and food drying efficiency. Future work will further optimise system design and materials to enhance efficiency and affordability while addressing the global challenge of sustainable water and food preservation.