Inland desalination

dehumidification

Humidification–dehumidification (HDH) is a distillation process (Fig. 17.14). The process is driven by the ability of air at higher temperatures to carry water vapor (Kabeel et al., 2013). This process consists of a humidifier, a dehumidifier, and a heater to heat carrier gas and the feedwater system (Narayan et al., 2010). A carrier gas is brought in contact with the feedwater. The air extracts vapor from the feedwater in the humidification zone. The distilled water is then recovered at the dehumidification zone, where the humid air comes in contact with a cooling surface causing condensation (Kabeel et al., 2013). This type of desalination technology consumes high energy and therefore various modifications have been evaluated. Modifications include the use of a multistage air-heated cycle, thermodynamic balancing, a mechanical compression-driven system, and hybrid systems with RO (Narayan et al., 2010).