Performance of a Modified Stepped Solar Still

Abstract

Distillation represents one of the earliest methods of treating water, and it remains as such in many parts of the world. A basin type solar still remains the simplest desalination technology, made up of a hermetic basin that is covered with a transparent airtight material such as glass or plastic. The system is simple, easy to construct, requires minimal maintenance, and cost effective. It is difficult maintaining minimum depth in conventional basin type solar still, as the area is large. However In an attempt to increase production per unit area by decreasing the thermal inertia of the water mass, this can be achieved in basin-type stepped solar still in which the area of the basin is minimized by having small trays. The purpose of this study were to design, fabricate and evaluate the performance of a modified stepped solar still. The theoretical analysis was conducted to determine the optimum design of the basin. The productivity and solar still efficiency were obtained by solving the energy balance equations for the absorber plate, saline water and glass cover, temperature difference between saline water and the glass cover. The results indicated that, the productivity of the modified stepped still is higher than that for conventional solar still approximately by 103%.