A solar still augmented with a flat-plate collector

A single-stage, basin-type solar still and a conventional flat-plate collector were connected together in order to study the effect of augmentation on the still under local conditions. The still inlet was connected to a locally made, fin-tube collector such that its outlet was fed to the still basin instead of the common storage tank. Measurements of various temperatures, solar intensities and distilled water productions were taken for several days at various operating conditions. Several modes of operation were studied: still connected to collector for a 24-h period; still connected only during sunlight hours from 8 am to 5 pm, and still operating alone for a 24-h period. These tests were performed using tap water and saline water as a feed. It was found that the mass of distilled water production using augmentation was increased by 231% in the case of tap water as a feed and by 52% in the case of salt water as a feed.

Experimental investigation of the solar still– collector system has shown that the productivity of the system was substantially increased in com- parison with that of the still alone. Meanwhile, efficiency was reduced by a few percentage points. The results of testing are grouped into five modes of operation. The first three are for fresh tap water as feed and the last two are for saline water feed, as follows: 1. The daily production of the still alone was about 2 L/m2.d, and its daily efficiency was about 27%. 2. When the still was operated with the collector for 24 h, its production was increased by 231% but efficiency was decreased by about 2.5% compared to that of the still alone. 3. A slight increase in condensate production (about 2%) over that of the previous mode occurred when the still was connected to the collector during daylight hours only (8 am–5 pm). 4. In operating the system with 35,000 of saline water, an increase in production of 52% was noticed when the still was connected with the collector over that of the still alone.