Effect of Water Salinity and Solar Still Dimensions on the Thermal Efficiency of a Conventional Solar Still

Laboratory of Energy Engineering, Materials and Systems, ENSA Agadir, Ibn Zohr University, Morocco.

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Published online: 22 May 2026

Abstract

The productivity of conventional solar stills simple devices used to obtain potable water from saline or brackish resources depends strongly on both the salinity of the feed water and the geometric characteristics of the unit. The present work examines the influence of these two parameters on still performance, with particular emphasis on how variations in salt concentration modify the efficiency of freshwater production. A numerical investigation is carried out for a conventional solar still operating under the climatic conditions of Agadir, using local profiles of solar irradiance, wind speed and ambient temperature as inputs. The system is described by energy balance equations applied to the main components of the distillation unit, and the coupled nonlinear differential equations are integrated using a fourth-order Runge-Kutta method. On this basis, the effects of seawater salinity and key operating conditions on the instantaneous and daily yield, as well as on overall solar still dimensions, are systematically analyzed.