Effects of wind and choice of cover material on the yield of a passive solar still

摘要

The development of an accurate thermodynamic model for the basic solar still has been the goal of many researchers. Glass covers are the most common choice of cover material, but are not always available under all situations and pose a large risk of physical injury if not handled with precaution. The effects of using three different cover materials (glass, Plexiglas, and plastic wrap) were investigated under a series of environmental conditions. The heat transfer model has been improved upon by the incorporation of a term for the effective emis-sivity of the cover, τ_(eff). The effective τ expands upon the definition of the basic τ by incorporating the reflecting effects of the condensed, but not yet collected, water droplets adhered to the interior surface of the cover. The cumulative yield and water temperature profile predictions of the improved model were verified by a comparison with experimental results.