solar still performance improvement using tar-coated blue metal stones: yield and efficiency analysis

The lack of fresh water is one of the most common issues people face. employing a solar still (ss) to transform saltwater into drinkable water can reduce the shortage of drinking water. still, the lower yield of ss remains a drawback. the use of energy storage materials can significantly improve an ss water output. four separate experiments were carried out:  ss, ss with tar-coated blue metal stones at a 1 cm water level (ss+tc-bms at 1 cm wl), ss+tc-bms at 2 cm wl, and ss+tc-bms at 3 cm wl. additionally, the thermal and exergy efficiency are assessed. the distilled water produced from ss+tc-bms at 1 cm wl was 3.82 kg, and ss+tc-bms at 2 cm wl was 3.29 kg, representing an increase of 59.4% and 37.2%, respectively, than the ss. the yield during the daytime (7 am- 6 pm) from ss, ss+tc-bms at 1 cm wl, ss+tc-bms at 2 cm wl, and ss+tc-bms at 3 cm wl were 2.32, 3.49, 2.91, and 2.15 kg, respectively. similarly, the generation of distilled water at night (7 pm to 11 pm) was 0.08, 0.33, 0.38, and 0.22 for ss, ss+tc-bms at 1 cm wl, ss+tc-bms at 2 cm wl, and ss+tc-bms at 3 cm wl, respectively. additionally, the ss+tc-bms’s diurnal thermal and exergy efficiency of the ss+tc-bms at 1 cm wl was 43.3%, and 2.2%, respectively. in contrast, ss’s diurnal thermal and exergy efficiency were 30.9% and 1.26%, respectively.