Design and Evaluation of a Desiccant-based Solar Still for Atmospheric Water Collection

A novel still design is proposed that employs a composite desiccant to adsorb atmospheric water vapor. The still has a pyramid design with two short windows and two large glass surfaces. The still is designed to be partially buried 15 centimeters into the ground for passive cooling of the condensing glass surfaces to improve condensation efficiency. An experimental setup is developed with a mud platform to study the performance of the still. A pyramid-shaped still of dimension 30cm x 30cm x 45cm (LxWxH) is fitted with thermocouples, humidity sensors, and a pyranometer to record the global irradiance. The data for two days, one with a buried still and the other unburied, of similar irradiance, are recorded from 6 am to 6 pm with a beaker containing water placed at the stage in the still. The results indicate a drop in glass temperature of about 10.42% in the buried setup compared to the unburied structure. This also resulted in the dew point being maintained for only 35% of the time in the unburied still compared to the buried still.