Comparative performance analysis of hemispherical solar stills using date and olive kernels as heat storage material

This study investigates the performance of hemispherical solar stills (HSS) enhanced with date kernels and olive kernels as heat storage materials to improve water distillation efficiency. By utilizing these natural and sustainable materials, the research highlights an alternative to synthetic options. Rigorous experimentation and detailed analysis under identical conditions reveal that both kernels significantly improve heat retention and water production rates. The HSS with date kernels (HSSDK) achieved a daily water productivity of 6.66 kg/m² day, representing an efficiency increase of 10.87%, while the HSS with olive kernels (HSSOK) produced 8.00 kg/m² day, enhancing efficiency by 13.54%. The cost per m³ of distilled water for HSSDK is approximately USD 4.65, while HSSOK costs USD 3.89, compared to USD 7.83 for the conventional CHSS system. These results demonstrate that the inclusion of heat storage materials has significantly reduced the cost of water production, with reductions of about 40% for HSSDK and 50% for HSSOK compared to the conventional system. These results are attributed to the high thermal conductivity and specific heat capacities of the kernels, enabling effective heat storage and gradual release. This study demonstrates the potential of agricultural by-products as cost-effective and sustainable solutions for solar water distillation. Further research is recommended to optimize the quantities and configurations of these materials, as well as to explore their integration with other renewable energy systems to enhance overall efficiency and sustainability.