A comparative assessment of innovative hemispherical solar distillers with cylindrical and conical fins: An experimental approach

Although the influence of fins on a basin's flat absorber will improve thermal performance and distillate production due to the increased heat transfer areas, many researchers are still interested in the problem of shading caused by fins, which reduces distiller productivity for some configurations of the fins designs. To obtain the best fin configurations that achieve the lowest shading effects and highest performance of hemispherical solar stills. The influences of absorbent cement layer with two types of fins (cylindrical and conical fins) with a diameter of 1.5 cm and a height of 3 cm at different gap spacing (3, 3.75, and 4.5 cm) were studied. To achieve these; three hemispherical solar stills were tested at same weather conditions, first is the conventional hemispherical still without fins (CHSWF) which represent the reference case. Second, is the cylindrical finned hemispherical still with gap spacing 3, 3.75, and 4.5 cm (CyFHS). Third, is the conical finned hemispherical still with gap spacing of 3, 3.75, and 4.5 cm (CoFHS). The results showed that, the cylindrical finned hemispherical still (CyFHS) productivity values are 5.55, 6.00, and 6.70 kg/m 2 , respectively, while conical finned hemispherical still (CoFHS) productivity values are 6.20, 6.65, and 7.15 kg/m 2 at gap spacing of 3, 3.75, and 4.5 cm, respectively compared to 4.20 kg/m 2 that was produced by CHSWF. The results showed that the use of conical fins achieves the highest performance of hemispherical still as a result of reducing the effect of shading. Whereas, the best configuration that achieves the highest performance is the use of conical fins with a gap spacing of 4.5 cm, where the rate of improvement is 70.24% compared to CHSWF