Synergetic Effect of Rubber Sheet and Jute Cloth on Solar Thermal Evaporation From Inclined Solar Still: An Experimental Approach

ABSTRACT The low freshwater productivity of passive solar stills remains a major barrier to their widespread deployment in water‐scarce regions. To address this limitation, the present study experimentally investigates the performance enhancement of an inclined solar still (ISS) using a bilayer absorber configuration composed of a rubber sheet and jute cloth. In this design, the rubber sheet serves as a sensible thermal energy storage and insulation layer, while the jute cloth functions as a hydrophilic porous wick to promote localized interfacial evaporation. Three configurations were tested under identical climatic conditions: a conventional ISS, an ISS with a rubber sheet, and an ISS with a combined rubber–jute bilayer absorber. Key performance parameters, including absorber, basin water, and cover temperatures, hourly distillate yield, and thermal efficiency, were measured and compared. The results show that incorporating the rubber sheet alone increased the daily freshwater yield and average thermal efficiency by 48.05% and 48.24%, respectively, compared with the conventional ISS, due to improved heat retention and delayed thermal release. The bilayer rubber–jute configuration delivered the best performance, achieving a maximum absorber temperature of , sustained elevated water temperatures during postpeak solar hours, and a daily freshwater yield of , corresponding to a 70.31% improvement over the baseline ISS. The average thermal efficiency increased from 23.34% to 39.75%, confirming a nonadditive, synergistic enhancement arising from the coupled action of thermal storage and wick‐assisted evaporation. Overall, the study demonstrates that integrating low‐cost, locally available materials into a bilayer absorber structure can significantly improve the thermal performance and productivity of ISSs, offering a simple, scalable, and sustainable solution for decentralized solar desalination applications.