Experimental Assessment of Hemispherical Solar Still Design with Reflectors

Freshwater scarcity is a significant and pressing problem on a global scale, with particular emphasis on regions such as the Middle East, Northern Africa, and different desert regions. These regions face severe challenges in accessing an adequate supply of freshwater resources. The scarcity of freshwater in these areas has far-reaching consequences, impacting various aspects of life, including agriculture, industry, and public health. To address this problem, solar distillation has emerged as a promising solution, utilizing renewable energy sources. However, the low efficiency of solar stills has hindered their widespread adoption. Hence, recent studies have focused on enhancing the efficiency of solar stills by examining different variables and implementing various designs. In accordance with this objective, a new experiment was conducted during the autumn season in the Kingdom of Bahrain to investigate a solar still with a hemispherical top cover for water desalination. The hemispherical cover was constructed using a 6 mm thick lexan plastic sheet, having a base diameter of 1m and a depth of 0.4m, resulting in a net effective area of 0.785
$\mathrm{m}^{2}$
. The findings revealed that this hemispherical solar still had an average daily water production rate of 3.610 liters per day. It is important to note that this yield was 11.1% higher than that achieved by a conventional single slope solar still with a
$20^{\circ}$
glass cover and a larger effective area of
$1\mathbf{m}^{2}$
, as observed in previous research conducted under similar climatic conditions. Additionally, by including curved Aluminum reflectors sheets that are
$1.2\mathbf{m \ \ x} \ \ 0.15\mathbf{m}$
, the hemispherical solar yield was increased by 5.5%. While the implementation of
$1.2\mathbf{m \ x} 0.3\mathbf{m}$
curved aluminum reflectors led to a further boost in productivity, showing an enhanced yield of 8%.