Performance evaluation of a humidification-dehumidification unit integrated with wick solar stills under different operating conditions

A comprehensive hybrid distillation system of humidification and dehumidification (HDH) unit incorporated by six wick solar stills was designed, fabricated, combined, and experimented to investigate the system performance. In the humidifier, different packing materials (aspen pad and thorn trees) and various water flow rates (1, 2, 3, and 4 kg/min) were investigated. The generated vapor in the humidifier was forced to be condensed in the dehumidifier. The desalination system was tested during the day- and night times. Performance of the wick stills was evaluated. The wick stills were fed by the brine hot water ejected from the HDH unit. Results revealed that using the aspen pad inside the humidifier provided greater freshwater productivity than that of the thorn trees. HDH unit packed with aspen pad at 4 kg/min produced the greatest distillate. At 4 kg/min, average gained output ratio (GOR) was raised from 2.5 for HDH unit working through the daytime only to 4.5 for the same unit operating through the day- and night times. Additionally, the hybrid system obtained a doubled productivity compared to HDH unit only, and the overall average GOR was increased from 5.1 to 5.7 with increasing the water flow rate from 2 to 4 kg/min.