Development of a rugged design of a high efficiency multi-stage solar still

Abstract The distillation unit is a stack of six rectangular cells forming a thermal series. In each cell, which is 4 cm thick a thin film of salty water is partially evaporated as it trickles over a heated vertical wall. The vapor produced is condensed on the opposite wall of the cell. The heat evolved by this condensation is used to evaporate the film trickling on the other side of the same plate, in the next cell. The unit produces more than 20 liters of distilled water per m 2 , par standard day, under the same conditions of sunshine that would give a production of 2.5 to 3 liters/m 2 day in a conventional, “single basin” solar still. This solar distiller is designed as a simple, rugged unit, easy to maintain and repair by any village craftsman with limited technical means.