A new design for a passive atmospheric multistage still

A new design for passive atmospheric multiple effect distillation unit is proposed. Inclined metallic surfaces covered with a cotton fabric and placed one over the other in a box are used. The cold salty water is fed only in the upper stage and flows along each surface, falling from one stage to the next by gravity, reaching finally a heated tray at the bottom. Vapour condenses below each surface and produces the water evaporation in the upper side of the same surface. Experiments have been performed with a prototype and the results are discussed and compared with the values obtained from a computational model. The model is used to evaluate the effect of changes in different system parameters. A small unit to be used by families in isolated areas is described.