Humidification-dehumidification water desalination system integrated with multiple evaporators/condensers heat pump unit

A study of the performance enhancement of a humidification-dehumidification (HDH) system integrated with multiple evaporators/condensers heat pump (HP) and heat recovery units is presented. The HP unit is intended to deliver necessary heating for humidifier and heating/cooling for dehumidifier in a new strategy. The proposed integrated system is capable to produce fresh water from the HDH system and HP unit. Four different configurations of the system formed by excluding/adding condensers and evaporators were investigated; mode-A (seawater precooling and reheating), mode-B (seawater reheating), mode-C (seawater precooling and humid air reheating), and mode-D (humid air reheating). Fresh water productivity, fresh water ratio, system water recovery, gain output ratio, specific work consumption, and fresh water production cost were used as performance measuring parameters of the system. The influences of operating parameters on the system performance were analytically studied and experimentally validated for different system configurations. The results indicate the enhancement of the systems' performance with increasing ambient air temperature and humidity, seawater and air flow rates, and with decreasing seawater temperature. The system configuration of mode-B shows the best performance with fresh water production of 61.94 kg/h and gain output ratio of 4.97 which are higher than those of the other configurations by 13%, 55%, 85% and 11%, 48%, and 75%, respectively. Comparisons of the proposed configurations with the other HDH desalination systems available in the literature were presented and better performance of the proposed systems was noticed.