Surface Area–Mediated Heat Transfer Enhancement And Thermal Energy Storage Integration For Productivity Improvement In Hemispherical Solar Stills

Abstract

This paper is numerical research of a hemispherical solar still (HSS) with eight basin fins based on the COMSOL Multiphysics software. There were four thermal energy storage materials under consideration such as phase change material (PCM), salt, sand and insulation. They were tested in two different configurations (no fins and eight basin fins) with regard to performance. The results of the simulation show that the overall productivity of all materials was significantly increased with the introduction of eight fins. The PCM with fins had the highest level of productivity (388.0), which was 174% higher than in the case of finless PCM (141.7). Insulation with fins gave a value of 373.3 (an increase of 133%), salt with fins gave a value of 357.8 (an increase of 152%), and sand with fins gave a value of 347.0 (an increase of 148%). The fins increase heat transfer by increasing the contact area between the basin plate and the storage medium, especially when using PCM because of its low thermal conductivity. PCM was not a good substitute to insulation, and worse still without fins. Latent heat storage capacity of PCM prolongs the distillation process after the sun has gone down and is therefore better than sensible storage materials such as salt and sand. The COMSOL simulations have provided comprehensive temperature and heat flux distributions that justify the trends that have been observed. In conclusion, the combination of eight basin fins and PCM would be the best design to obtain the highest freshwater production in a hemispherical solar still. The study offers important information on how to maximize solar desalination systems with the help of numerical simulation.