Techniques used to enhance condensation rate of solar desalination systems: State-of-the-art review

The use of solar energy to generate drinking water has been widely considered due to its cost-effectiveness and zero pollution footprint. The freshwater productivity and the effectiveness of solar desalination is directly impacted by the temperature difference between the brackish water and the solar desalination cover. Over the recent years, various methods have been utilized to boost the water temperature and reduce the cover temperature to increase the freshwater production of solar still systems. This study reviews various methods used to decrease temperature of the cover and enhance the condensation rate of the solar desalination system. In addition, an extensive effort has been made to compare the generated water of solar still systems by different cover cooling methods such as thermoelectric cooling (TEC), water cover cooling, air cover cooling, nanofluid cover cooling, and shading, considering geometry of the system. Moreover, a enviro-exergo-economic comparisons between different studies was reported and discussed for a better understanding of high-performance and low-cost designs of solar stills applications. The results concluded that the shading cover cooling technique does not significantly impact the water productivity of solar still systems. In addition, the results of previous investigations show that unsuitable cover cooling methods in tubular solar still desalination can decrease the water productivity.