Performance improvement of tubular solar still with pistachios shell materials: Energy, exergy, economic, and sustainability analysis

This study is based on the effects of using a tubular solar still (TSS) with pistachio shells of macro size as an energy storage material for generating high water extraction from the solar still. Two different solar stills are used for performing the distillation process, in which one still is accommodated with pistachio shells for storing solar energy to escalate water productivity. Energy and exergy analysis were performed along with the calculation of the freshwater production for both modified tubular solar stills (MTSS) and conventional tubular solar stills (CTSS) without a heat storage facility. The results indicate that the modified distillation apparatus yielded more fresh water, collecting about 2.41 kg from the saline water, whereas the non-modified still obtained 1.91 kg. This represents a 27.3 % enhancement in the performance of the modified still. The thermal efficiency of both systems is also evaluated with MTSS achieving a maximum efficiency of 39.15 % whereas CTSS achieved 26.15 %. Furthermore, the exergy efficiency of the systems is evaluated, where the maximum exergy efficiency is attained as 3.82 % and 2.22 % for MTSS and CTSS, respectively. In economic analysis CPL and payback time of the study are also evaluated, and it is found that the CPL of MTSS and CTSS is obtained as 0.027 $/l and 0.031 $/l, and 0.443 years and 0.515 years, respectively.