Heat and Mass Transfer Processes and the Performance Evaluation in Single-Slope Solar Stills

The paper reviews the present understanding of the analysis of the heat and mass transfer processes in single-slope solar stills. By using the results of published experiments, it is proposed that the heat and mass transfer phenomena from the basin water to the glass cover are coupled. This coupling makes it possible to derive the dependence of the heat transfer coefficient for condensation on the inclination of the glass cover of the still. The derived relation, i.e., Nu(con) = 0.738 (Gr(con)*Pr-con*sin beta/Ja*)(1/4) A(-1) where A is the aspect ratio, has been demonstrated to be an important expression for predicting the heat transfer coefficient for condensation h(con) necessary for a more realistic evaluation of the overall efficiency of single-slope solar still of a given cover angle beta.