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.