Recent Developments of Solar Stills and Humidification De-humidification Desalination Systems: A Review

Freshwater shortage refers to the ongoing depletion of available water resources. The World Economic Forum identified this issue as the most significant global risk affecting all continents based on its potential impact over the next decade. According to the United Nations (UN) world review, up to 40% of the population will be impacted by freshwater scarcity by 2030 due to climate change. Many attempts to convert seawater to potable water were made via many techniques that need a huge amount of energy, like multi-stage flash, multi-effect thermal desalination, or reverse osmosis. Some methods of seawater desalination can be executed by renewable energy. Solar desalination systems are introduced here in a comprehensive review study to show the importance of energy and cost-saving. In this study, Recent developments in solar desalination hybridization are reviewed to focus on the productivity, cost, and energy efficiency of combining solar energy and other disciplines. Hybridization aims to optimize the heat energy source, minimize the potable water cost, and maximize freshwater productivity. This review introduced modern techniques accompanied by solar desalination, like geothermal energy, concentrated solar power, photovoltaic modules, humidification dehumidification techniques, and evaporation enhancers. The estimated cost comparison between hybrid solar desalination studies is presented besides their thermal efficiency and gain output ratio. Results showed that maximum energy efficiency was 72%. It was achieved with compact flat solar still with ultra-hydrophilic glass cover. The minimum cost of one litre produced freshwater was 0.011 USD/L (about 0.17 LE/L) in the case of solar desalination with copper chips, nanofluid, and PCM.