Effect of solar area concentration ratio on performance of a conventional solar still with air humidification-dehumidification

The high demand for drinking water increased the need to develop new economic methods for water desalination. Conventional solar stills suffer from latent heat losses resulting from water-vapor condensation on the inner surface of the glazing. Using open humidification-dehumidification process with conventional solar stills is a potential area in water desalination nowadays. Integrating a vertical duct to the still for generating a natural draft and solar-air preheater improved its performance. The effect of the solar area concentration ratio on the still performance with heater was studied thoroughly compared to no heater as a reference. Using a condenser in the duct prevents latent heat losses on the inner surface of the glazing and utilizes it to preheat the feed water. This arrangement improved the still productivity. A model was generated to describe the efficiency of the system using three area concentration ratios: 0.5, 0.625, and 0.75. The results showed that the still productivity increased proportionally with the area concentration ratio with average productivity of 5.5 l m(-2) day. (C) 2015 AIP Publishing LLC.