The performance of the capillary film solar still installed in South Algeria

Abstract

Solar distillation is an attractive process to produce potable water using cost-free solar energy. This energy is used directly for evaporating water inside a device usually termed a solar still. In arid zones, desalination of brackish water may be the only solution for a supply of freshwater. The current water shortage extends to include underground water supplies, previously considered to be an unlimited resource. This paper presents a modeling and experimental research of solar distillation applied to the Sahara arid regions. The aim of this work is an improvement of the efficiency and production rate of fresh water by using solar distiller with capillary film. This solar distiller was designed and patented by R. and C. Ouahes and P. Le Goff. It is made up of identical evaporation-condensation cells. The brine to be evaporated is a thin film impregnating a fabric assumed to be very thin and adhering by capillary forces to the wall of the plate. Its advantage reside in the reuse of latent heat of steam condensed in the one stage, for water evaporation in the subsequent stage. The study on the performance of this solar still has been conducted under the actual insulation at the South of Algeria: in an experimental station near Touggourt (Algerian Sahara). In this arid land, there is brackish underground water; therefore, solar desalination is necessary to produce drinking water. The theoretical analysis of the heat and mass transfer mechanisms inside the solar distiller have been developed. The measured performance was then compared with the results obtained by a theoretical analysis of the heat and mass transfer processes of the solar distillation systems.