Abstract A common assumption in the mathematical analysis of solar stills is that the heat capacities of the basin liner and glass covers are negligible compared to that of water. This work investigates the error invoked when this assumption is applied by including these thermal capacities into the analysis. A double-basin solar still is considered, and its output is calculated both with and without consideration of heat capacities of the liner and glass covers. For the basin liner, six materials have been considered for the liner, namely stainless steel, iron, copper and aluminium, graphite and rubber. Results show that neglecting the heat capacity of the basin liner leads to significant overestimations of daily distillate output, with approximately 4.01% for stainless steel, 3.8% for iron, 3.5% for copper, 2.6% for aluminium, 1.9% for graphite and 2.1 % for rubber. In contrast, neglecting the heat capacities of the glass covers has a minimal impact. The overestimation is only about 0.49% when the lower glass cover's heat capacity is ignored, and just 0.17% when the upper glass cover's is excluded. These findings indicate that, for accurate simulation and performance prediction of solar stills, the thermal capacity of the basin liner should be considered, while that of the glass covers can be safely neglected.
Verma et al. (Thu,) studied this question.