A Comparative Study of Hemispherical Solar Stills With Various Modifications to Obtain Modified and Inexpensive Stills Models 

Abstract

This study is intended to comparative and analyze the operational performances of the conventional hemispherical solar still (CHSS), hemispherical solar still with glass cover cooling (HSS-C), and hemispherical solar still with CuO-water based nanofluid (HSS-N). To Obtain the best modifications that achieve the highest productivity with the lower inexpensive. The conventional hemispherical still (CHSS) was utilized as the reference case to investigate the best modification. In the first modification, CuO nanoparticles with three different concentrations (0.1, 0.2, and 0.3%) were added to the basin water, to increase the intensity of absorbed solar energy, improve the thermal properties of basin fluid, and then increase the rate of vapor generation inside the distillation basin. In the second modification, water film glass cooling technology with three different flow rates (1.5, 2, and 2.5 L/h) was utilized to increase the water vapor condensation rate. The experiments test of the three distillers (CHSS, HSS-N, and HSS-C) was conducted at the same weather conditions at 1 cm basin fluid depth. The average daily accumulative yield of CHSS is 3.85 L/m2/day, while the daily accumulative yield of HSS-N increases to 5.75, 6.40, and 6.80 L/m2/day with improvement 49.3, 66.2, and 76.6% at volume fraction 0.1, 0.2, and 0.3%, respectively. Also, the daily accumulative yield of HSS-C increases to 4.9, 5.35, and 5.7 L/m2/day with improvements of 27.3, 39, and 48% at water film flow rates of 1.5, 2, and 2.5 L/h, respectively. The cost of distilled water produced from CHSS is 0.0106 $/L, while the utilization of HSS-C (2.5 L/h) and HSS-N (0.3%) reduces the cost of distilled water to 0.0072 and 0.0066 $/L, respectively. Based on accumulative yield and economic analyzes, it is recommended that utilized the modified HSS-N (0.3% volume fraction) to achieving the highest accumulative yield and the lowest price of the produced distilled water.