Thermal performance of a triple-basin solar still

Abstract

A transient mathematical model is presented for a triple-basin solar still. It is based on an analytical solution of the energy-balance equations for the various elements of the still. The energy-balance equations are solved analytically using the elimination technique. System performance was investigated by computer simulation. Numerical calculations were performed on typical summer and winter days in Tanta (latitude 30°47′ N) for different water masses in each effect of the still and also for various wind speeds ( V) to study the effect of these parameters on the daily productivity of the system. It was observed that the daily total productivity of the still decreases with the increase of water mass in each basin. The total productivity was a maximum for the least water mass in both the lower and middle basins without dry spots over the base of each effect. Moreover, it was found that the daily total productivity of the still increases with the increase of V up to a typical velocity ( V t ), beyond which the increase in productivity becomes insignificant. The value of V t is independent of the water mass in each effect, but it showed some seasonal dependence. On a typical summer day, the daily total productivity of the still was found to be 12.635 kg/m 2/d, which agrees well with the results reported in the literature for triple-effect solar stills.