Influence of Water Depth on Internal Heat and Mass Transfer in a Double Slope Solar Still

Abstract

In this work, an attempt has been made to study the effect of water depth on the internal heat and mass transfer in the single basin double slope (DS) solar still. The experimental setup was fabricated from Galvanized iron sheet. The bottom and all sides of the still are made from same material. The cover is made from a transparent glass of 3 mm thickness. The solar still was sealed to reduce the leakage of vapor to the surroundings. The study covers the influence of different environmental and operational parameters on the still productivity. Environmental parameters include solar intensity, ambient temperature and wind speed. Operational parameters are feed water quantity, water depth and orientation. The influence of operational parameters on the internal heat and mass transfer, and hence on the productivity of the still of a DS solar still was studied and compared with that of a single slope (SS) solar still. Both SS and DS solar stills of the same area are fabricated and tests conducted by maintaining the depth of water in the basin at 0.01m, 0.025m, 0.05m and 0.075m after fixing the orientation. The maximum distillate output of 3.07 L/m2/day was obtained with water depth in still basin 0.01m in the DS solar still with north-south orientation. The results indicated that decrease in depth of basin water, resulted with increase in productivity of the still.