Paper Title
Optimum Design for a Stepped Solar Still to Maximize The Productivity

Abstract
The Levenberg-Marquardt Method (LMM) is utilized to determine the optimum design variables for a stepped solar still with a glass cover water film cooling device to maximize the productivity of the distillate. The design algorithm is based on the minimization of the functional of the problem and estimation of the optimal design variables of glass cover water film cooling devices. The accuracy of the present numerical solution for distillate is first verified by comparing the values with those provided by El-Samadony and Kabeel. Next, four different designs are considered in the present work, and the resultant daily amount of distillate for each stepped solar still with glass cover water film cooling device are examined. The results indicate that utilizing the optimal design variables for glass cover water film cooling devices can indeed increase the productivity of distillate, and the percentages of increase are calculated as 1.81%, 4.85%, 4.27%, 3.88%, and 2.93% for cases A, B, C, D, and E, respectively. Keywords- Optimum Design, Stepped Solar Still, Maximize The Productivity