Figs. 4 and 5present the theoretical and experimental results of the hourly yield for passive and active mode respectively for different depths of water
in the basin. From Fig. 4, it is observed that there
is a fair agreement between the experimental and
theoretical results for 0.05 m water depth in the basin in the passive mode of operation. However, for
higher depths (0.10 m and 0.15 m), the fluctuation
between the experimental and theoretical results is
large. This large fluctuation may be attributed to
the fact that for higher depths of water in the basin,
the water temperature in the still is well below 50C
and also the difference in water and inner glass temperature is less than 17C as proposed by Dunkle.
For the case of 0.10 m and 0.15 m depth of water
in the basin, the water temperature is so much less,
during the morning hours, than the inner glass temperature that the rate of distillate output (_ qew) and
finally the yield (_ mew) theoretically becomes negative