Theoretical and numerical assessment of an enhanced Humidification-Dehumidification desalination system based on Indirect Evaporative cooling and Vapour Compression Refrigeration

In this work, a theoretical study and a numerical performance analysis of a novel HumidificationDehumidification (HDH) desalination system, that simultaneously exploits an Indirect Evaporative Cooling (Maisotsenko cycle, IEC) device and a Vapour Compression Refrigeration cycle (VCR), are proposed. The IEC device is here employed as a very efficient saltwater evaporator-air humidifier, by an optimized mass exchange process between saltwater and working airstream. Both thermal exchanges of the VCR cycle are used: the hot coil pre-heats the inlet air to enhance the effectiveness of the evaporation process, while the cold one provides the cooling capacity to condense freshwater. The numerical model is based on data of actual commercial devices and considers their effective operational mode. The parametric analysis and the yearly simulations in different climatic areas show very promising results (GOR and RWA factor equal to 3.4 and 5.0.106 in the best operative condition, equal to 3.2 and 4.1.106 in the best climate situation) that lead to consider this technology as very competitive among HDH desalinations systems.