Abstract This study examines the use of computational fluid dynamics to analyze and simulate the 3D modeling of a solar desalination plant with a single slope design. It aims to optimize large-scale desalination by investigating factors like glass cover angle and fin placement. Results show that a 15° glass cover produced the most freshwater (0.2957 kg/m2·h), while a 60° angle decreased production by 8.63%. Adding fins increased freshwater production by 53.32% and improved heat transfer efficiency. These findings contribute to developing an optimized solar desalination model to enhance efficiency, reduce energy consumption, and lower carbon emissions.