Investigation of structural parameters for inclined weir-type solar stills

Abstract

The solar still, in which saline or brackish water is converted into freshwater using renewable solar energy, can be an effective solution to water scarcity. Inclined solar stills are well-known due to their high production yields compared to other types of solar stills. In this study, an inclined weir-type solar still was developed as a modified inclined solar still with an emphasis on the effect of structural parameters, such as weir height, distance between weirs, and distance between the absorber plate and the condenser cover, on distilled water production. The optimal values of structural parameters for the maximum freshwater production were specified by the response surface methodology and a quadratic model derived from a Box-Behnken design model. The results showed that the operational variables of the inclined weir-type solar still system significantly impacted the water production volume. Using a weir height of 2 cm, a distance of 3.5 cm between weirs, and a distance of 15 cm between the absorber plate and the condenser cover, the maximum water production volume was achieved at 6.474 kg m⁻².day⁻¹. The selected model had R2, Radj2 and Rpred2 values of 0.9978, 0.9939, and 0.9756, respectively. The maximum and minimum volumes of the produced water were obtained as 6.64125 and 1.79792 kg m⁻². day¹, based on the multiple response prediction of the variables. According to the validation tests, the model’s accuracy in prediction of the maximum amount of freshwater production was notable (97.49%).