A 2E Analysis and Optimization of a Hybrid Solar Humidification-Dehumidification Water Desalination System and Solar Water Heater

This study presents an energy-exergy analysis of a Humidification-Dehumidification (HD) solar water desalination system. The extensive application of the HD system lies in its low energy consumption and ability to exploit solar energy to supply all the heat energy demands. The unsteady governing equations were solved until the system reached a steady state. The simulations were done with the Euler approach to solving the system of energy balance equations numerically. This study's main goal was to investigate the effect of different configurations of the hybrid system and various operating conditions on the performance of the solar HD water desalination system. The optimum configuration was selected based on thermodynamic and exergy analyses. The effects of important parameters such as inlet water and air mass flow rate in the humidifier and dehumidifier water temperature and mass flow rate on the system's operation were studied. This paper also explored the feasibility of the extra heat as a domestic water heater under various conditions. Based on exergy analysis, it is shown that the solar desalination system with air-water preheater with the power of 1057.9 W had the most exergy destruction in comparison with the two other systems (i.e., water preheater system and air preheater system with the respective exergy destructions of 901.3 W and 75.3 W). Comparing the values of freshwater production, exergy destruction, and exergy efficiency, the solar system with a water preheater was selected as the optimum one.