The cavity geometry of a single-slope solar still directly influences the internal transport phenomena by altering natural convection, heat transfer, and vapor movement, as their alteration collectively determines the system’s freshwater productivity. Variations in the glass cover inclination modify the cavity geometry, thereby changing the natural convection flow pattern, evaporation, and condensation mechanisms, as well as the overall thermal behavior of the solar still. Despite its importance, the impact of cavity geometry on the internal transport phenomena has not yet been fully understood. Therefore, the present work conducted a systematic two-dimensional numerical investigation to assess the effects of five glass cover inclination angles (10°, 15°, 20°, 25°, and 30°) on the thermo-fluid behavior and freshwater productivity. To isolate the influence of cavity geometry, the basin length and front-wall height were kept constant, while the back-wall height was varied to produce the desired inclination angles without altering the remaining design parameters. The numerical results confirmed that modifying the glass cover inclination induced a substantial change in the natural convection flow regime within the still cavity, leading to significant nuances in heat and mass transfer characteristics. At steeper inclination angles, the airflow was dominated by a single large recirculating convection cell that confined convective heat transfer between the evaporating water surface and the glass cover, causing a uniform reduction in the effectiveness of condensation and freshwater production. In contrast, the shallowest inclination angle of 10° promoted the formation of multiple localized convection cells that enhanced fluid mixing, strengthened convective heat transfer, and improved vapor transport toward the condensing surface. Consequently, the 10° configuration exhibited the highest freshwater productivity among all investigated geometries.
Open Access
Journal Metrics
Journal Overview
Associated Journals