Theoretical and experimental parametric study of modified stepped solar still

In this paper, a stepped basin is used to improve the performance of solar still. An experimental as well as theoretical investigation is carried out. Two solar stills are used simultaneously and both use saline water; a conventional single sloped solar still and a modified stepped solar still. The influence of depth and width of trays on the performance of the stepped solar still is investigated. Feed water temperature to the stepped still is varied using a vacuum tube solar collector. For further augmentation of the yield a wick on the vertical sides is added to the stepped still. A good agreement between the experimental and theoretical results is observed. The results show that the productivity of the stepped solar still strongly depends on the tray depth and width. Also it is found that maximum productivity of stepped still is achieved at a tray depth 5. mm and tray width 120. mm, which is about 57.3% higher than that of the conventional still. In this case the daily efficiency and estimated cost of 1. l of distillate for stepped and conventional solar stills are approximately 53%-0.039$ and 33.5%-0.049 $ respectively. © 2012 Elsevier B.V.