Experimental and Numerical Analysis of a PCM-Supported ...

exchanger and energy storage in one unit. The nature of both working fluids in
gaseous immiscible state for charging and liquid state for discharging processes
enables such compact design where both working fluids can flow in the same porous
channels.
Figure 2.19: Schematic illustration of hybrid latent heat storage and spray
flash evaporation system [141]
2.8.8 Summary of the literature on HDH systems
This section extracts and summarizes the important results and experiences of
previous investigations in literature and focuses on some of the interesting
developments. Different systems have been proposed in literature including
open/closed water and air loops, with/without air heating, with/without water heating,
and forced/ natural air circulation. In all cycles of HDH units, the latent heat of
condensation is utilized in preheating the feed saline water in shell and tubes heat
exchangers or direct contact condensation in packed columns.
The main axes in developing the humidifier and dehumidifier through various
designs and configurations were focusing on improving the heat and mass transfer
rates by increasing the gas-liquid interfacial area and achieving multi-stages or multieffects.
These developments are mainly classified as open-water/closed air (OWCA)
cycle and open-air/closed water (OACW) cycle. OWCA systems are the most
commonly used, more efficient, and hence they have been studied extensively in the
literature.
Most of the realised approaches are using forced convection for actuating the air
flow between evaporator and condenser. Various shapes of packing elements were
used and investigated by different authors. The factors influencing the choice of a
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