Augmentation of thermo-environmental performance of hemispherical distiller utilizing low-cost thermal energy storage materials: A comparative study

This study explored the potential of two thermal energy storage materials – sand before demineralization (SBMR) and minerals after sand removal (MASR) – to boost the daily output of a hemispherical solar still (HSS). Both materials were prepared and characterized before being integrated into the HSS system for sensible heat storage. Additionally, the study focused on evaluating the effect of varying material depths, spanning from 0.25 cm to 2 cm, to identify the optimal depth for maximizing the HSS's performance. Two experimental setups were conducted: with and without an external condenser. A thermoenviroeconomic analysis was carried out to compare the performance of the modified HSS (MHSS) with SBMR, and MHSS with MASR to the conventional HSS (CHSS), both with and without the external condenser. Our findings demonstrate that a material depth of 0.75 cm optimizes productivity for MHSS configurations. Furthermore, incorporating an external condenser significantly enhances both thermal performance and productivity. Energy efficiency considerably increased, MHSS with SBMR showing a 57.13 % improvement and MHSS with MASR exhibiting an 88.35 % improvement over CHSS. Exergy efficiency also saw substantial gains, with the most significant improvement (85.26 %) observed in MHSS with MASR utilizing an external condenser. Daily yield was highest for MHSS with MASR, reaching 6.08 kg/m² (an 88.24 % increase), followed by MHSS with SBMR at 5.06 kg/m² (a 56.66 % increase). Regarding production costs, MASR-equipped MHSS without an external condenser achieved the most significant cost reduction (36.47 %) compared to CHSS.