Efforts toward performance enhancement of a stepped solar still for the concentration of sugarcane juice

Concentrated sugarcane juice is a raw material used to manufacture a number of value-added products. At present, the sugar industry ingests the maximum amount of fuel for obtaining concentrated sugarcane juice, which in turn leads to degradation of the environment. This study addresses the unexplored application of aluminum nanoparticle-enhanced beeswax, a sustainable bio-PCM, in solar still systems (SSS) for sugarcane juice evaporation, evaluating its thermal performance using simple and modified collectors to enhance energy efficiency and promote eco-friendly distillation in rural settings, at a flow rate of 25 mL/min. Among the tested systems, the stepped solar still having nanoparticle mixed beeswax and a modified collector is found to be the most economical, thermally more stable, and eco-friendlier. This system produces a maximum distillate output (4930.2 g) with the most concentrated sugarcane juice having a brix value of 32.8°B. The average convective heat transfer coefficient is found to be maximum for the stepped solar still having nanoparticle mixed beeswax and a modified collector, which is 14.29 to 57.96% higher than the other developed units. This system is also found to lead other systems with maximum values of carbon credit earned ($1137.1), CO₂ mitigation (56.85 tons), total productive cost ($0.96), thermal efficiency (64.8%) and exergy efficiency (3.91%). This study concludes that the stepped solar still having nanoparticle mixed beeswax and a modified collector might be an affordable and environmentally friendly tool to evaporate water from sugarcane juice, which could help the NCS industry in attaining the sustainability goal.