Solar water heating
Practical Action
The following are some encouraging examples of progress evident in some developing countries
over the last 10 years or so:
A School
(India, 1997)
Whilst working in conjunction with a charity and an aid organisation, Marios Cleovoulou
constructed a solar water heating system largely from local recycled materials to improve the
physiotherapy work undertaken at a school for handicapped children. Although Cleovoulou
admits that the system may not be the most efficient, it was made viable through his ability to
keep the costs to a minimum. The most expensive component of the system was the 250litre
tank which cost approximately US$36 (£22). Although this one component is more than most
of the people in rural India can afford, the costs saved on fuel were a significant benefit.
The system itself was a direct, passive system operating as a thermosyphon with a flat plate
collector. Several innovative solutions were engineered, further reducing the costs. The
insulation of the hoses connecting the collector to the tank was particularly interesting as this
was achieved through the linking together of plastic bottles, top to bottom, and feeding the
hose through the centres of each one.
A certain degree of control was afforded through the incorporation of a tap on the cold water
inlet, another on the hot water outlet and a stopcock on the cold water intake. This design
allowed the system to operate in two ways, either as a pressurised system or an overflow
system, incorporating a certain degree of flexibility into its use. The staff were also able to use
the cold water inlet as a second source of water, although training was required to ensure the
system was still able to operate effectively, i.e. the tank would be refilled.
Marios Cleovoulou’s description of the development and installation of this system is
informative and can be found on his website.
(Cleovoulou.com, 1997)
Affordable community collector (Brazil, 2002)
Jose Alano, a retired mechanic in Brazil has single-handedly had a large impact on the
application of solar water heaters in Brazil through his development of a solar collector
constructed using 100 recycled plastic bottles and 100 recycled milk cartons. The collector
operates using the thermosyphon effect as part of a direct and passive system. Whilst
providing a more attainable solution to solar water heating in Brazil and reducing fuel costs,
this invention also has the added benefit of combating the waste removal problems
experienced in Brazil.
This invention has won Alano the Superecologia prize and he now gives lectures and leads
workshops in schools and community centres around Brazil. In Santa Catarina state, Alano’s
home state, his invention has improved the lives of over 7 000 people. The total number of
collectors installed in another state rose to 6 000 in 2008.
The rise in the number of installations of this technology and its availability to the general
population of Brazil has been enhanced through the publication of a “DIY Leaflet”. This
coupled with the workshops lead by Alano and others has meant people are able to construct
their own systems.
(How to make a solar water heater from plastic bottles, 2002)
Community installation (Cote d’Ivoire, 2001)
This project addressed the problems inherent in the importing of solar water heaters such as
higher costs and consequently reduced accessibility to the rural population of developing
countries such as Africa. The production of solar water heaters locally was therefore
investigated and with great success.
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