Exergy, exergo-economic, environmental and sustainability analysis of pyramid solar still integrated hybrid nano-PCM, black sand, and sponge

A sustainable and cost-effective technique for desalinating water with solar energy to alleviate the freshwater scarcity is the solar still. In this study, four different cases including the case-I: conventional solar still (CSS), caseII: CSS with fins and black sand, case-III: CSS with fins, hybrid enhanced nano PCM, black sand and sponges, case-IV: CSS with fins, hybrid enhanced nano PCM, crushed stone and sponges have been comprehensively investigated in terms of thermal, productivity, exergy, economic, environmental and sustainability point of view. The assessments were executed at the Rajshahi (latitude: 24 degrees 22'N, longitude: 88 degrees 36'E), Bangladesh. Later, the performance case-III was investigated by using river (Padma) water and discolored water, respectively. Average thermal efficiency on daily basis of case-III is about 32.44 % and 6.47 % higher than case-II and case-IV due to the improved heat storing configuration. In addition, cases-II, III, and IV all had exergy efficiency improvements of 18.89 %, 74.75 %, and 53.54 %, correspondingly in comparison to case-I. For cases I, II, III, and IV, the payback periods are 185, 159, 126, and 135 days, accordingly. In cases-I, II, III, and IV, modified SS results in cost-per-litre reductions of 73.5 %, 77.29 %, 81.89 %, and 80.63 %, correspondingly, as compared to market prices. Cases-I, II, III, and IV ' s energy production factors are 0.137, 0.099, 0.138, and 0.195 yr(-1), respectively. The research also supports the claim that adding fins, sponges, black sand, and hybrid enhanced nano-PCM to CSS results in a higher sustainability index.