Optimization of condensing tray shapes for a multi-effect solar still coupled with parabolic solar collectors for domestic wastewater treatment: A comparative study

The issue of water depletion emerged as a life-threatening problem for the world due to urbanization, groundwater over-extraction, industrialization, and global warming. Current study aimed to address this issue by proposing a solution to distill wastewater using a multi-effect solar still. The study optimizes two condensation tray shapes, U and V, based on the yield produced and the temperatures achieved. Two solar still units with four stages of U and V-shaped trays were connected to a parabolic solar collector. To determine the optimal tray shapes, a rigorous optimization process was carried out using SolidWorks 2020. The optimization process yielded optimum heat flux values of 3.04e⁰¹ and 2.84e⁰¹ W/m² for U and V-shaped trays, respectively. Higher the value of heat flux suggested more energy available for condensation. Which was corroborated by physical findings that the U-shaped condensation tray was more efficient, producing an average per day yield of 2.519 L/m² h compared to the V-shaped tray's yield of 2.041 L/m² h. The findings provide strong evidence that the U-shape is a better tray shape for condensation purposes. Maximum yield for both units was observed during the peak temperature time between (13:00–15:00 h), indicating a direct correlation between yield and atmospheric temperature.