Experimental analysis of solar still equipped with porous rubber sheet as energy storage material

Due to technological advancements and an increase in population growth, the need for freshwater has escalated. Several techniques have been developed to produce fresh water, and one of the promising techniques is using the solar thermal desalination process. This study conducts experimental analysis on a single slope solar still employing porous rubber sheet thermal energy storage. Various experiments were performed with water masses ranging from 10 to 25 kg within the basin, comparing these to a similar setup lacking sensible heat energy storage. The results showed that the increased water mass in the basin reduced the distilled water produced from the Solar still (SS) with and without sensible thermal energy storage. The highest distilled water produced from the SS in both cases was at the lowest mass of water. The SS with porous rubber sheet produced maximum distilled water of 0.85 kg/m², whereas the SS without rubber sheet was found to be 0.75 kg/m² at the lowest water mass. Similarly, the highest distilled water collected occurred at different time intervals, and the mass of water in the basin as the stored energy is liberated to the water at different times of the day. The augmentation in the distilled water produced from the SS with a porous rubber sheet may be due to the higher absorption of heat and improved surface area of water with solar radiance. Furthermore, at the lowest water mass, the average daily efficiency of the modified SS with porous is higher, reaching about 55.6%, which is higher compared to the SS without porous rubber sheet as thermal energy storage, and the average daily efficiency decreases with increased water mass inside the basin on both the cases. The exergy analysis revealed that the average exergy efficiency improved to about 4.69% from 3.54% using a porous rubber sheet in the basin for the lowest water mass of 10 kg as compared to the SS without any material.