Evaluation of transparent acrylic stepped solar still equipped with internal and external reflectors and copper fins

This study experimentally evaluated the effect of combining stepped solar still with copper fins, transparent step walls and internal and external reflectors on its fresh water production and daily efficiency, compared with a conventional single-basin solar still tested under the same environmental conditions of hot arid area in Qena City in Upper Egypt territory, during daytime starting at 7:00 a.m. until 7:00 p.m. in summer conditions. The experimental results revealed that the new stepped solar still attained 129% increase in fresh water production compared with the conventional still. The results also showed that the daily efficiency of the modified stepped solar still reached about 63%, which was found to be higher than that for other stepped solar stills in the literature. Moreover, the daytime-accumulated fresh water per day attained up to 8285 ml/m(2)/day for an optimum seawater depth of 30 mm in stepped basin, with an additional 630 ml/m(2)/day of fresh water accumulation during nighttime. Furthermore, the produced fresh water can be used directly in different human applications, due to its acceptable levels of pH, turbidity, conductivity and total dissolved solids (TDS). Therefore, the modified stepped solar still is recommended for the use in remote and hot arid areas.