Enhancing water productivity and cost-effectiveness in hemispherical solar stills using sandy beds, reflectors, and a vapor extraction fan

Abstract

The objective of this study was to enhance the performance of hemispherical solar stills (HSS) through experimental investigations utilizing various types of sand beds as thermal storage materials. The research examined the influence of sand type (yellow and black) and sand bed heights (1, 2, and 3 cm) on the efficacy of HSS. Additionally, the study explored the effects of external reflectors and a vapor extraction fan on the performance of sand-based HSS. The experimental results indicated that HSS using black sand demonstrated superior performance compared to other operating conditions in terms of both productivity and efficiency. Particularly, the most significant improvement in performance for the black sand hemispherical solar still (BSHSS) was observed when employing reflectors and a fan with a sand bed height of 1 cm, resulting in a substantial 154% increase in production, where the production for hemispherical SS and BSHSS + fan and reflectors was 4100 and 10400 mL/m2.day, respectively. Under these optimized conditions, the thermal efficiency of BSHSS + R + F reached 56%. In conclusion, an economic analysis was conducted, revealing that the cost for water treatment was $0.022 per liter for the conventional hemispherical solar still (HSS) and $0.012 per liter for the BSHSS equipped with reflectors and a condenser. These findings represent a significant advancement in enhancing the feasibility and efficiency of solar distillation systems, thereby addressing the global challenges of water scarcity and environmental sustainability.