Solar power-driven humidification-dehumidification (HDH) process for desalination of brackish water

In this study, a photovoltaic (PV) panel-driven humidification-dehumidification (HDH) treatment process was studied for desalination of brackish water under a free or forced convection mode. A bench scale reactor was performed to purify sodium chloride (NaCl)-simulated brackish water. Primary factors affecting the evaporation and condensation rates were evaluated. The water evaporation and condensation mass flow rates were increased with the increasing evaporative brackish water temperature. And the decreasing cooling water temperature increased the water condensation rate. Under their respective optimal conditions, the forced convection mode accomplished a higher freshwater yield than the free convection mode. With the forced convection, the highest freshwater yield was 0.873kg{dot operator}m^-2{dot operator}d^-1 achieved at the evaporative temperature T₀=64.3°C. A preliminary cost analysis showed that the water produced (free convection) from the solar power-driven HDH desalination process had a cost similar to that of drinking water from traditional water treatment plants. This study demonstrated that the HDH treatment was technically and economically feasible for desalination of brackish water.