A comparative energy and exergy efficiency study of hemispherical and single-slope solar stills.

In this experimental work, a comparative energy and exergy efficiency study of hemispherical solar still and a single-slope solar still has been carried out. The experiments were conducted in southeast Algeria on 25-5-2020 and 3-6-2020 in the natural climatic environment, and daily accumulation of distilled water produced for both distilleries was measured. The maximum obtained cumulative yield of distilled products is equal to 5.38 kg/m/day for the hemispherical solar still, and 3.64 kg/m/day for the single-slope solar still. The overall daily productivity was improved by 47.96% for the hemispherical solar still compared to the single-slope solar still. The maximum daily energy efficiency of the single-slope solar still is 25.81%, and hemispherical solar still is 38.61%. Similarly, the maximum daily exergy efficiency of single-slope solar still is 1.8%, and hemispherical solar still is 3.1%. The main conclusion from the study is the hemispherical distillery greatly enhances productivity as compared to the single-slope distillate and gives more efficiency. Thus, the hemispherical solar still is recommended to be used to provide safe drinking water from salty water.