Experimental Evaluation of the Shadow Effect on the Single-Slope Solar Still Performance

The shadow effect is one of the major problems hindering the operation of solar energy-based systems and affects the performance of solar stills. The shade cast by the still's lateral walls on the basin reduces the solar-exposed area and reduces the daily distillation yield. This article deals with an experimental study to evaluate the shadow effect on the conventional solar still (CSS) performance. A comparative analysis was conducted between the single-slope CSS and the modified one (modified solar still [MSS]) with three glasses. Therefore, outdoor experiments were performed in hot and cold weather conditions in Adrar—Algeria. The results showed that replacing wooden walls with transparent glass is not always efficient, and the still's thermal performance depends on the weather conditions. On the summer day, the daily productivity reached 3.57 kg/m² for the CSS and 4.42 kg/m² for the MSS (a reduction of about 24% compared with the MSS). On the winter test day, the glass side walls appeared to negatively impact the MSS distillate yield, which was 5.55% lower than the CSS yield (2.57 vs. 2.71 kg/m² for CSS). Energy and exergy analysis show that the MSS is more efficient than the CSS on summer days, whereas the opposite happens on winter days.