Solar Still

Solar still is an apparatus where brackish water is distilled utilizing Solar Energy. For a tropical country like Sri Lanka which is blessed with more than 270 good sunny days, solar distillation of water is an appropriate technology. The efficiency of the Solar Still is further increased when it is used in dry zone of the country.

Construction :
1. Use of blackened corrugated metal sheets increases the heat absorption capacity.
2. Either concrete panels or metal sheets can be used for the cover box, of which the upper surface is a transparent glass. The glass is glued on to the cover box.
3. Underneath the corrugated tray there is a layer of insulation of coir fibre.
4. Brackish water inlet and the distilled water outlet ( PVC sockets) are placed as shown in the picture.

Operation :
1. The solar insulation makes the internal temperature to rise due to the phenomena knows as “green house effect”
2. The hotter dry crests transfer the heat to the water troughs. The water is heated by this method as well as direct solar energy.
3. Water which condenses on the under surface of the glass trickles down along it and falls on to the channel at the lower end.
4. The water which gets collected into the channel is withdrawn at an outlet.