Energy, exergy, and economic analysis of solar still using coal cylinder fins: an experimental study

The phenomenon of drinking water scarcity has turned into the foremost issue that the world's populace is facing today. The Algerian desert regions, including the El Oued region (southeastern Algeria), also suffer from drinking water shortages, despite the presence of huge quantities of underground salty water. Solar distillation is among the easy and cheap solutions to solve this problem because this method relies on renewable energy (solar energy) as a key factor in providing drinking water from saltwater. As solar energy is intermittent energy, energy storage is required for augmenting the yield. Coal cylinders are low cost and locally available materials that can be used as fins and energy storage materials. In this research, two solar stills such as conventional solar still with a black absorber (CSS-BA) and CSS with a black absorber and coal cylinders (CSS-BA&CC) were fabricated and tested. The CSS-BA&CC produced a potable water yield of about 4.16 kg per day while the CSS-BA could only produce 2.88 kg, which is 44.44% lower when compared to the CSS-BA&CC. The thermal efficiency was noted to be 22.04 % and the exergy efficiency is 1.07 % in the CSS-BA. Similarly, the thermal efficiency is 32.46% and exergy efficiency is 1.90% for the CSS-BA&CC. The experimental results proved that the potable water yield of the CSS-BA was enhanced by coal cylinders (sensible heat energy storage material -SHESM) which is a locally available low-cost material.