An innovative solar still design integrated with radiative cooling for sustainable, passive, all-day freshwater harvesting: A comprehensive study

This study investigates the application of radiative cooling, a cutting-edge approach gaining significant attention, to enhance condensation efficiency in solar stills, addressing the limitations of these eco-friendly devices. Two designs were explored: one with an opaque, radiative cooling-coated metal chamber adjacent to the glass, and another replacing the glass with a transparent radiative cooling plate. Using a novel two-dimensional numerical and CFD method, validated by experimental results and relying solely on radiation and temperature as environmental parameters, the study evaluates these designs’ effectiveness. Additionally, the impact of single- and double-layer windshields at night was assessed, along with Atmospheric Water Harvesting using the transparent radiative cooling design. This design showed a 23.5% increase in water production and a 24.2% improvement in energy efficiency. For the chamber-based design, various geometries were analyzed using dimensionless numbers to optimize performance, yielding a 12.5% increase in production and a 2.7% rise in energy efficiency. Integrating a Parabolic Trough Collector to preheat water at the basin of the solar still amplified these gains, leading to 260.4% production and 65.3% efficiency improvements. These findings demonstrate that radiative cooling can significantly enhance sustainable solar desalination efficiency without additional energy input, offering promising potential for future research.