DOUBLE EXPOSURE SOLAR STILL

ABSTRACT Desalination of sea water through solar still utilization is considered as a long-term solution for the fresh water shortage problem, especially in arid areas. Improvement of solar still productivity, besides their design simplicity, are the most important aims of the new studies in the solar distillation field. This work deals with a new method of increasing the productivity of a simple solar still. It is based on raising the evaporator temperature inside the still as a result of increasing the quantity of solar radiation incident on the evaporator. This effect is carried out by exposing the water basin evaporator to the solar radiation at both its upper and lower surfaces. Therefore, the unit is called a Double Exposure Solar Still. The new distillation unit has been constructed and is being run at Cairo High Polytechnical Institute, or at the Shoubra Faculty of Engineering. Outdoor experiments were carried out on both basic and modified units to study the effect of natural conditions on the performance.