Fig. 6 shows the productivity of the still as a
function of the basin water depth, it is evident
that the productivity decreases with the increase
of water depth. This increase in still productivity
as the depth decreases could be attributed to the
lower heat capacity of the basin water that results
in a higher temperature in the basin and increase
the evaporation rate. It can be concluded that the
output of the still is maximum for the least water
depth in the basin (20 mm). The 20 mm depth
was used for all experiments in order to determine
different effects on the solar yield.