Experimental study of productivity enhancement in a humidification-dehumidification desalination system through various packing materials and configurations

Packaging materials significantly enhance the efficiency of the humidification—dehumidification (HDH) desalination system. The configuration of split packing materials has not been investigated, and there is a lack of studies assessing packing materials of varying heights and types. To address this deficiency, an experimental humidification-dehumidification cycle has been established utilizing packing at 30 cm split and full heights, in addition to 45 cm and 60 cm full heights. Furthermore, three types of packing materials—cellulose kraft paper, PP and PVC cellular grid, and PP trickle grid—are examined. The operational parameters include inlet water temperature and flow rates set at (50 ˚C, 60 ˚C, and 70 ˚C) and (2 kg/min, 4 kg/min, and 6 kg/min), cold water flow rates at (8 and 16 kg/min), air cycle types (closed and open), and a unified air flow rate of 1 kg/min. The efficiency of the HDH system reaches its peak when the inlet and cold water flow rates are at their maximum values of 6 and 16 kg/min, respectively, with the inlet water temperature at highest of 70 °C, utilizing cellulose kraft paper of the maximum height of 60 cm, and operating under a closed air cycle. The optimal performance of the HDH system yields a fresh water productivity of 4.2 L/h, a gained output ratio (GOR) of 0.63, humidifier and dehumidifier efficiencies of 98.7% and 84%, respectively, a recovery ratio (RR) of 1.2, a fresh water cost of $0.008/L, and a pressure drop of 0.32 Pa across the humidifier. The 30 cm split packing demonstrates improvements in productivity and GOR of 3% and 4%, respectively, when compared to the 30 cm full-height packing.