The storage effect in the basin increases as the water depth increases, and hence, the overall water temperature decreases for a given amount of solar energy. Because of the low operating temperature, the rate of BMS 753 also decreases, and hence, the daily yield and thermal efficiency decrease. It was concluded that the yield is maximum at the optimized flow velocity of 1.8 m/s.
Kumar and Tiwari  evaluated the daily yields for multi effect active solar distillation systems by solving one-order coupled differential equations by Runge–Kutta method. The numerical computations were done for hourly variation of various temperatures, yield and overall thermal efficiency up to the fourth effect of the distillation unit. The predicted results were validated by an experimental setup of single effect with one collector connected with the basin. The multi effect solar distillation unit was coupled with a subatomic particles panel of flat plate collectors as shown in Fig. 56.
Fig. 56. Schematic of multi effect active solar still coupled with flat plate collector panel .Figure optionsDownload full-size imageDownload as PowerPoint slide