A solar desalination plant for domestic water needs in arid areas of South Algeria Original Research Article

The shortage of drinking water in many areas of the world is now a serious problem. At least 80% of arid and semi-arid countries, like Algeria, where 40% of the worldʹs population live, have serious periodic droughts. To resolve this crisis, different methods of solar desalination have been used in several countries. Among these is solar distillation — a process where solar energy is used to distil fresh water from saline or brackish water for drinking purposes and other applications. It is generally classified into passive and active distillation systems. The work on passive solar distillation has been reviewed by Malik et al.[1], the work on active solar distillation system was carried out by other researchers. It is well known that in solar distillation, the radiation from the sun evaporates water inside a chamber at a temperature higher than the ambient. The principle of operation is the greenhouse effect provided by the glass cover. Energy balances are made for each element of still; solar time, direction of beam radiation, clear sky radiation, optical properties of the cover, convection outside the still, convection and evaporation inside are accounted. The most studied model is the solar distiller, which has the following advantages: low installation cost, independent water production at the point of use and no need for trained maintenance staff. But it has important disadvantages, such as low efficiency and problems associated with the deposit of salt, deposit of scale and corrosion. The aim of our research work is to develop a highly efficient solar distillation system of simple construction, applicable in small units of production. It concerns a device of a solar distiller with heat recovery; it is a solar distiller for arid zones that should be very simple, handy, and easy to maintain and repair by every village artisan with limited technical means. The study on the performance of this solar still has been conducted under the actual insulation at the South of Algeria, where the feed water is brackish underground geothermal water. Theoretical analyses of the heat and mass transfer mechanisms inside this solar distiller have been developed. The measured performance was then compared with the results obtained by theoretical analysis of the heat and mass transfer processes. The results clearly show that the efficiency is increases with the increase of solar radiation flux and with the increase of brine temperature. There is an optimum value of feed water (brine) when the efficiency is maximum. The efficiency increases when there is a recovery of latent heat of condensation.