The perfect (water) distiller for remote areas. A solar still is a low-tech way of distilling water, powered by the heat of the sun(more precisely, the heat & humidity of the soil, and relative cool of the plastic). Two basic types of solar stills are box and pit stills. In a solar still, impure water is contained outside the collector, where it is evaporated by sunlight shining through clear plastic.
The pure water vapour (and any other included volatile solvent) condenses on the cool inside plastic surface and drips down off of the weighted low point, where it is collected and removed. The box type is more sophisticated.
High performance solar still (Patent US 4235679)
A solar still into which cold seawater is fed by means of a pipe perforated along its horizontal length. The seawater then flows down an inclined plane through a black wick material placed on top of a double or parallel plate base which serves as a heat exchanger that transfers heat from a working fluid to the seawater. The seawater in turn evaporates while flowing down the wick and the vapor condenses as pure water on the upper inner surface of the still transferring heat back to the working fluid which is being circulated through the upper cover of the still. The vapor condensate is collected as it flows down the inclined upper inner surface and in turn is drawn off; the working fluid is recirculated to continuously heat and then cool the distillate.