Increase in Distillate Productivity by Inclining the Flat Plate Reflector of a Tilted-Wick Solar Still in Summer

Abstract

Abstract: A tilted-wick solar still with a flat plate reflector inclined backwards is theoretically analysed to predict the distillate productivity of the still on a summer solstice day at 30oN latitude. We are proposing a new geometrical model to calculate the solar radiation reflected by the inclined reflector and then absorbed onto an evaporating wick. Using this method, we performed a numerical analysis of heat and mass transfer in the still in order to determine the effectiveness of the inclination of the reflector. We found that the benefit of a vertical flat plate reflector is negligible, while an inclined reflector can increase the distillate productivity of the still, and that the reflector angle should be set at about 20o backward from vertical on a summer solstice day. The benefit of the inclined reflector is less in summer than in winter, but the daily amount of distillate can be increased about 9% or 6% by using an inclined reflector when the length of the reflector is a half of the still’s length and the still’s angle is 10o or 30o.
Key words: Solar still; Solar distillation; Solar desalination; Tilted-wick; Reflector; Inclined; Summer