Harvesting dew water for human use in coastal area of Gujarat (India)

This paper describes the development of technology to harvest (condense and collect) dew water for use of people living in coastal area of Gujarat province, north-west India. Potable water is severely scarce in the area, such that extra supply of even tens of liters a day could add to water security of the households. A R&D program was initiated in the year 2001-02, after it was noticed that dew occurred more frequently and in larger quantity here than inlands. Dew water is extracted from air using condensers made of special plastic film which cool rapidly at night by radiating heat to atmosphere. Dew condensing efficiency of the plastic film appears to be comparable to blades of grass, natural vegetation. A four year R&D program led to design of large working systems after testing of prototypes and pilot units. Large dew harvest systems have been erected on roofs (condenser-on-roof), open ground (condenser-on-ground). Technology is simple, uses material available in the area and is amenable to do-it-yourself procedure.