Effect of partial intermittent shading on the performance of a simple basin solar still in south Algeria

Algeria is considered a dry country due to the severe scarcity of its water resources. Low-density population areas lack not only fresh water availability, but in most cases electrical power grid connections as well. Fortunately, these areas are blessed with high renewable energy and huge underground water resources. The water has a salinity of 2-5 g/L in most places. The main aim of our research has been to study the effect of desert climatic conditions on the performance of a simple basin solar still. A small-scale solar powered distillation unit has been constructed and operated. The experiments were conducted in Ouargla, south of Algeria. Three series of experiments were performed. The first consisted of studying the solar still under local climatic conditions. The bottom and the sides of the still were lagged with an additional 100 mm insulation layer of local dune sand in the second series. The daily output in the first series was found 6.01 L/(m2 d). This amount was improved in the second series by about 33.7%. The third series consisted of lowering the glass temperature, by an intermittent shading of the north glass cover. This procedure resulted in a further 12% enhancement in the daily distillate output.