Experimental insights of a novel stepped solar distiller by augmenting condensing cover cooling and heat recovery mechanisms

Water scarcity in arid and coastal regions underscores the need for efficient desalination methods, especially for high-salinity sources that are not suitable for traditional reverse osmosis systems. This investigation delves into the design and efficiency of a stepped solar distiller incorporating novel elements like a condensing cover cooling mechanism (CC) and a heat recovery (HR) system. The study, carried out in Gujarat, India, from May to June 2024 under four configurations standalone SSS, SSS with CC, SSS with HR, and SSS with both CC and HR assessed distillate production, thermal effectiveness, and sustainability. The findings reveal that the SSS-CC-HR variant yielded the highest daily water output at 5.9 L/day, surpassing the standalone SSS by 17 %. The cooling of the glass cover decreased its temperature by 20 %, elevating condensation and evaporation rates. The evaporative heat transfer coefficients for SSS-CC-HR, SSS-CC, and SSS-HR were 43–50 % greater than the individual setup, contributing to average thermal efficiencies of 40 %, 39 %, and 38 %, respectively. The exergy efficiency of SSS-CC-HR reached 5.6 %, marking an 80 % improvement over the standalone SSS. This research illustrates that integrating cover cooling and heat recovery significantly boosts solar distillation performance, offering a practical solution to freshwater scarcity in coastal regions.