| Summary: | Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2015. === Access to adequate quantities of clean drinking water has become a serious issue on the
worldwide level. This is particularly true in arid and rural areas where for the majority of
people water is a limited and a vulnerable resource. These water sources which are often
highly contaminated are potentially the cause for several diseases (waterborne diseases) and
ultimately death especially in infants. Due to poverty and sometimes to the remote conditions
of their regions, the population is unable to afford adequate water purification technologies,
since they are relatively expensive and energy intensive. It is therefore vital to investigate
appropriate water purification technology that people can afford or construct, operate and
maintain themselves.
A promising technology is solar distillation for the supply of drinking water on a small-scale
level. It has proved to be a unique purification method as it can purify almost any type of
water by using the high solar energy potential of the affected regions. The most basic form of
solar distillation is the use of a single basin single slope solar still. However the downside of
this technology is that it presents a low efficiency and productivity. To try to tackle this
problem, many studies have been carried out to enhance productivity, effectiveness and
efficiency of single-basin solar stills.
In this present study, a solar distillation unit was designed, fabricated and experimentally
tested. Its performance in terms of distillate output and energy efficiency was analysed under
Cape Town conditions and compared to similar stills that have been reported in the literature.
The main configuration of the solar still is a double glazed single basin solar still coupled to
an external condenser.
The study indicated that the performance of the solar still unit can be enhanced by increasing
the evaporation rate which is a combined effect of solar radiation, ambient temperature, and
the system components temperature. It was concluded that the applied techniques such as the
external condenser, double glazing, good insulation and low level of water are effective. The
unit was found to have an efficiency ranging between 21 and 29% over the test period and a
mean distillate yield of about 2.5 litres per square meter was achieved per day.
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