COMPUTER 'MODELLING FOR THE SYSTEM PERFORMANCE OF A SOLAR POWERED DISTILLATION PLANT FOR THE - SEA. COAST AND DESERT HABITATS

Abstract

The double-effect solar still, considered in the present work, consists of three distinct plates the top glass cover, the intermediate glass plate and the absorber plate. The thermal performance of such a still depends on the heat capacity of these three plates. Fig.7 shows a schematic diagram of the aforesaid solar still to be analyzed. The still consists of one glass cover at the top and one absorbing plate at the bottom, as well as one glass plate in the middle ; all of these plates are in parallel. In order to collect more insolation, the equipment is tilted from the horizontal. Accordingly, several weirs [21 ] are installed in parallel on the upper surface of the glass plate to hold the saline water, while a blackened wet jute cloth is ,placed on the upper surface of the absorbing plate to form the liquid surface. Except for the glass cover, all parts of the enclosure are carefully insulated with a thick layer of asbestos to make the heat loss as low as possible. During operation, the top glass cover and intermediate glass plate transmit. solar radiation and-the absorbing plate is then heated directly by solar radiation. The saline water feeds are introduced on the upper surfaces of both the absorbing and intermediate glass plates, where some water evaporates, while the remainder is -collected at the bottom and discarded as concentrated brine. The vapour produced from the saline water rises from the absorbing plate and is condensed on the lower side of the intermediate glass plate. The heat of condensation given 17 up by the condensing vapour on the lower side of the glass plate is conducted through this plate and furnishes heat to evaporate an equivalent amount of water from the saline water sliding down the upper side of the plate. Finally, the heat of condensation given up by the condensing vapour on the lower side of the glass cover is transmitted