Prediction and measurement of mass transport in experimental solar stills

The aim of the present investigation was the derivation of validating field measurements from an experimental passive solar still model suitable for the evaluation of the existing theory, on the internal heat and mass transfer processes in solar distillation systems. A very good agreement was found between measurements and predictions from the basic model which was originally developed by Dunkle. However, it was surprising that although this model, with its simplified assumptions relaxed, was successfully validated against measurements at least as far as lower and intermediate temperatures and mass flow rates as high as about 0.1 g/m2 s is concerned, its prediction accuracy was found to degrade for higher, up to 0.2 g/m2 s measured yields, corresponding to modified Ra numbers up to about 6 106, while it was also derived that the modified Ra number is clearly a crucial dimensionless quantity which determines the heat and mass transfer processes in solar distillation systems. 2011 Elsevier Ltd. All rights reserved