Solar distillation apparatus

Abstract

According to one aspect of the invention, a system is disclosed for substantially continuous distillation of water which comprises a plurality of parallel distillation units each comprising series of fluid and preferably also Fresnel-type lenses. Water to be distilled is preheated by circulating it through the fluid lenses on which evaporated water vapor is condensed to produce distilled water. The quantity of water circulated in the lenses is many more times the quantity of water evaporated by the solar energy concentrated by the lenses and condensed per unit of time to allow the circulated water to carry off heat recuperated within the lenses and the system. The preheated water circulated through the lenses is discharged into a central container in which the foci of the fluid and Fresnel-type lenses are located. Secondary containers are provided to receive overflow from the central container since preheated water may be discharged into the central container faster than it is being evaporated. Preferably heat exchangers having a heat exchange fluid therein are provided in the secondary containers to recover heat from the water therein. This system also may include or be combined with turbines and or a separate solar energy concentrator and collector used to superheat the heat exchange fluid and also preferably to heat excess water vapor removed from the distillation system and convert it to superheated steam and/or to externally condense the excess water vapor.