Solar Thermal Energy for Desalination Purposes: Research
and Development of Solar Distillers Applied to the Brazilian Semi-Arid Region.
Solar desalinator; desalination; fresh water; renewable energy;
separation processes; social technologies.
In this study, a solar desalination model was developed and tested aiming
to meet the demands for drinking water for human consumption in the Brazilian semi-
arid region. Understanding the models of solar incidence in the real system and the
possibility of increasing radiation collection in the desalination basins through equipment
design, a preliminary computational study was conducted to define the best architecture
for the test site conditions. Seeking to maintain basic premises so that the solar desalinator
can become a viable technology for decentralized communities in the Brazilian semi-arid
region, the project favored the simplicity of design and the careful choice of cheap,
accessible, chemically safe, and environmentally friendly construction materials. The
proposed construction methodology aims to scale these systems in a simple way, using
the same modular construction platform, using precast lightweight expanded polystyrene
concrete parts. Tests using black paint as a photocollector element resulted in
accumulated productions reaching 4.38 kg/m2/day, surpassing the reference system
production by 72.1%. With only 4% of commercial activated carbon as a photocollector
element, distilled water production reached 3.35 kg/m2/day, exceeding the reference
production by 74.4%, with an average salt removal of 99.4%. Another advantageous
feature is the possibility of semi-batch operation without interference in distilled water
production, greatly reducing costs with feed control systems and brine outlet, for
example. Due to its unique characteristics, the modular solar desalinator has demonstrated
potential to become an alternative and effective social technology in mitigating the effects
of drought in the Brazilian semi-arid region.