|Ashrafi, N. (2002). Potentially viable solar powered appliances cooling and distillation. PhD, Institute of Technology, Sligo.
|Stand alone solar powered refrigeration and water desalination, two of the most popular
and sought after applications of solar energy systems, have been selected as the topic of
research for the works presented in this thesis.
The water desalination system based on evaporation and condensation was found to be
the most suitable one to be powered by solar energy. It has been established that highoutput
fast-response solar heat collectors used to achieve high rates of evaporation and
reliable solar powered cooling system for faster rates of condensation are the most
important factors in achieving increased outputs in solar powered desalination systems.
Comprehensive reviews of Solar powered cooling/refrigeration and also water
desalination techniques have been presented. In view of the fact that the Institute of
Technology, Sligo has a well-established long history of research and development in the
production of state of the art high-efficiency fast-response evacuated solar heat collectors
it was decided to use this know how in the work described in this thesis. For this reason
achieving high rates of evaporation was not a problem. It was, therefore, the question of
the solar powered refrigeration that was envisaged to be used in the solar powered
desalination tofacilitate rapid condensation of the evaporated water that had to be
The principles of various solar powered refrigeration techniques have also been reviewed.
The first step in work on solar powered refrigeration was to successfully modify a
conventional refrigerator working on Platen-Munters design to be powered by highoutput
fast-response evacuated solar heat collectors. In this work, which was the first
ever successful attempt in the field, temperatures as low as —19°C were achieved in the
A new approach in the use of photovoltaic technology to power a conventional domestic
refrigerator was also attempted. This was done by modifying a conventional domestic
refrigerator to be powered by photovoltaic panels in the most efficient way. In the
system developed and successfully tested in this approach, the power demand has been
reduced phenomenally and it is possible to achieve 48 hours of cooling power with
exposure to just 7 hours of sunshine.
The successful development of the first ever multi-cycle intermittent solar powered
icemaker is without doubt the most exciting breakthrough in the work described in this
thesis. Output of 74.3kg of ice per module with total exposure area of 2.88 m2, or
25.73kg per m2, per day is a major improvement in comparison to about 5-6kg of ice per
m2 per day reported for all the single cycle intermittent systems. This system has then
become the basis for the development of a new solar powered refrigeration system with
even higher output, named the “composite” system described in this thesis.
Another major breakthrough associated with the works described in this thesis is the
successful development and testing of the high-output water desalination system. This
system that uses a combination of the high-output fast-response evacuated solar heat
collectors and the multi-cycle icemaker. The system is capable of producing a maximum
of 141 litres of distilled water per day per module which has an exposure area of 3.24m2,
or a production rate of 43.5 litres per m2 per day. Once again when this result is
compared to the reported daily output of 5 litres of desalinated water per m per day the
significance of this piece of work becomes apparent.
In the presentation of many of the components and systems described in this thesis CAD
parametric solid modelling has been used instead of photographs to illustrate them more
The multi-cycle icemaker and the high-output desalination systems are the subject of two
|Solar saline water conversion plants
|Potentially viable solar powered appliances cooling and distillation
|Institute of Technology, Sligo
|Creative Commons Attribution-NonCommercial-NoDerivs
|Mechanical and Electronic Engineering ITS