Analysis of the process of solar desalination with emphasis in the humidification and dehumidification method

ABSTRACT

The lack of water is a problem that affects many regions in our planet, specially in very dry places and isles. Experts say that this situation will worsen, and that by 2025 about 1.8 billion people will suffer with water scarcity. Although traditional desalination methods are well-known and implemented alternatives to obtain fresh drinking water, they are not environmentally sustainable, because they are generally supplied by non-renewable fuels, whose combustion intensifies the greenhouse effect, causing disequilibrium to the environment. Another option that has been developed along the years is the desalination by solar energy. Since it is a clean, abundant and renewable type of energy, it is already a good option to isolated regions, whose demand is low or medium. Some technics are shown in this work, which focuses on the humidification-dehumidification desalination method. This technique has shown to be the most efficient one, due to its energy reuse. There is still a long way to go in order to make it viable in large scale, especially in terms of water production, specific energy requirement and specific cost of water production. However, solar desalination by humidification-dehumidification has proven to be a sustainable, promising technic which is reasonably costly and simple to operate. Therefore, the authors encourage more investments in researches in Brazil in the area of solar desalination and use of its rejects, aiming at the production of fresh water in Brazilian regions lacking it.

Keywords:
solar desalination; humidification; dehumidification; renewable energy; energy reuse; energy efficiency