Thermal Solar Energy for Distillation Purposes: Development of a Modular Solar Desalination Plant for the Brazilian Semiarid
Desalination; renewable energy; separation and mixing operations; social technologies.
In this study, a solar desalination plant was developed and tested to meet the demands of drinking water for human consumption in the Brazilian semi-arid region. Understanding the solar incidence models in the real system and the possibility of increasing radiation collection in the desalination basin based on the equipment design, a preliminary computational study was carried out to define the best architecture for the test site conditions. In order to maintain basic premises so that the solar desalination plant can become a viable technology for decentralized communities in the Brazilian semi-arid region, the project prioritized the simplicity of the design and the careful choice of cheap, accessible, chemically safe and environmentally correct construction materials. The proposed construction methodology aims to scale these systems in a simple way, from the same modular construction platform, using pre-molded pieces of lightweight expanded polystyrene concrete. Tests using black ink as a photocollector element resulted in accumulated production that reached 4.38 kg/m²/day, exceeding the production of the reference system by 72.1%. With only 4% of commercial activated carbon as a photocollecting element, distillate production reached 3.35 kg/m²/day, exceeding the reference production by 74.4%, with an average salt removal of around 99.4%. Another advantageous feature is the possibility of semi-batch conduction, without, however, interfering with distillate production, greatly reducing costs with control systems for feeding and brine output, for example. Due to its unique characteristics, the modular solar desalination plant has demonstrated the potential to become an alternative and effective social technology in mitigating the effects of drought in the Brazilian semi-arid region.