Utilisation of new technique to improve the efficiency of horizontal solar desalination still

It is a well-known fact that the energy used in the process of desalinating seawater is directly proportional to the amount of salt extracted from the water. Very small portions of fresh water consumed in each house is used for drinking and cooking, the rest is used for flushing, cleaning, and watering the garden and other purposes. In order to reduce the energy consumed in this process and hence the energy impact on the environment it is desirable to supply each house, from centralised desalination plants, with relatively high salt content water good enough for all domestic purposes other than drinking. Then each household produces its own drinking water by installing small solar desalination stills on the roof or in the garden. For any desalination unit to be domestically acceptable its efficiency should be reasonably high while its capital and running cost should be relatively low, and probably be partly integrated within the water system of the house. The existing conventional small solar basin stills have some drawbacks that make them inefficient to be used as domestic units. This paper highlights some drawbacks that exist in the evaporation and condensing zones of the horizontal solar desalination stills, and introduces new techniques developed at the University of Bahrain to improve the efficiency of both evaporating and condensing zones and suggesting a new cheap method of storing excess solar energy during the day, for the continuation of the process at night. Exhaustive data collected over a few years are analysed and presented to show the effectiveness of the new techniques in improving the efficiency of the small solar desalination units.