The thermal performance of an ethanol solar still with fin plate to increase productivity

This article presented an indoor experiment on developing a mathematical model for predicting the productivity of an ethanol solar still of basin type. The test still contained a horizontal evaporating surface and a condensing surface inclined 14° to a horizontal. Various concentrations of ethanol–water solution were employed for this experiment. The distillation temperature range included boiling point. The collected data were used to estimate the mass-transfer coefficient and mass transfer conductance of the solar still. Accordingly, a mathematical model was developed based on the Spalding theory of convection and the Fick's law of diffusion. In order to increase the performance at the outdoor conditions, a basin solar still was integrated with a set of fin-plate fitting in the still basin for distillation of a 10%v/v alcohol solution. It was found that the productivity of the modified solar still was increased by 15.5%, compared to that of a conventional still. Moreover, the predicted still efficiency by the model could increase to 46% when a number of fins that raised an effective absorptance were increased. Condition of high concentration output and high productivity was investigated. Monthly mean productivity and efficiency of the still were found to increase with daily mean insolation.