Optimized construction of marble pieces as thermal storage materials for performance improvement of hemispherical solar distiller

The present work aims to obtain the optimized construction of marble pieces as thermal energy storage materials that achieves the highest performance of the hemispherical solar distillers. To obtain the optimal construction of the marble pieces as energy storage materials, four different marble pieces (black marble pieces, green marble pieces, red marble pieces, and white marble pieces) were placed on the basin of hemispherical distillers and tested under the same climate conditions. To achieve this goal, three hemispherical distillers were designed, constructed, and tested under the same climatic conditions; the first is the classical hemispherical distiller (CHD) which represents the reference case, the second and third hemispherical distillers contains marble pieces. The experiments were conducted in two stages, in each stage; two types of marble pieces are tested and compared with the reference case. The experimental results showed that the utilization of red marble pieces represents the optimal construction of marble pieces, which led to improving the cumulative productivity of hemispherical solar distillers to 7.75 l/m2 days compared to 4.8 l/m2 day achieved by the CHD, with an improvement of 61.46 %. The accumulative thermal efficiency of CHD reached 39.25 %, while the utilization of red marble pieces improved the accumulative thermal efficiency to 62.98 %. Also, the use of red marble pieces reduced the distillate cost by 35.6 % compared to the reference distiller.