Solar distiller efficiency enhancement via optical concentration and thermal storage: Challenges, materials, and future directions

A more sustainable process of desalination is solar stills, which are typically limited by a low absorption of heat and low evaporation rates. This paper discusses the use of mirrors and sun concentrators to improve thermal performance, increase freshwater production, and efficiency. These optical improvements increase the rate of phase transition by enhancing solar radiation on the evaporation basin to produce productivity benefits of up to 200 percent under experimental conditions. Further, phase change materials (PCMs) and nanomaterials are more effective in storing heat, and this enables an extended operation to continue even during hours of darkness when the sun may not be shining. Though these improvements add significantly to still performance, other issues like optical degradation, thermal nonuniformity and cost effectiveness are still to be considered in large-scale uses. Future developments ought to aim at long-lasting coating, AI-enhanced solar tracking, and energy coupling to improve its efficiency and reliability.