Energy, exergy and cost analysis of different hemispherical solar distillers: A comparative study

The experimental study of the results of reflective aluminum foils, metal sheets, and phosphate granules on the productivity and efficiency of hemispherical solar stills was given throughout this work under the solar conditions of the city of El-Oued (Algeria). Solar stills were designed, manufactured, and tested in August 2020. A standard hemispherical solar still was made of wood and coated with black silicon. It was considered a traditional solar still. Although it was compared to traditional solar stills, it was improved by covering its side walls with reflective aluminum foil, zinc metal sheets, and copper sheets. It had been found that the productivity of the modified still was 8.67%, 29.08%, and 42.35%, respectively, on top of that of the traditional solar still. This could be due to the activity of the foils and metals, which reflect more radiation and store energy, increasing the temperature of the salt water in the basin. In the second experiment, three modified solar stills in line with aluminum foil and phosphate granules (30 g/L), zinc metal sheet and phosphate granules, and copper metal sheet and phosphate granules were collectively used. It had been found that the productivity of the modified solar still with aluminum foil and phosphate granules (the improvement rate is 30.61%) was on the far side of that with zinc metal sheets and phosphate granules (the improvement rate is 49.961%) and copper metal sheets and phosphate granules (the improvement rate is 62.24%).