This paper presents the study of a new generation of water desalination installation by solar energy using the SMCEC principle (Solar Multiple Condensation Evaporation Cycle). The good quality of distilled water obtained by this new concept favours its use for producing water for drinking and irrigation. The work presented in this paper includes modelling, simulation and experimental validation for this type of installation. The models of the different sections of the unit are developed from the governing heat and mass transfer equations. These models permit the sizing of the solar collectors, the evaporation tower and the condensation tower. The numeric simulation of the models allows the study of the relation among the different control parameters of the unit that would optimise its production. The obtained results are then compared against the experimental results.