A novel configuration of reverse osmosis, humidification-dehumidification and flat plate collector: Modeling and exergy analysis

In this paper, modeling and exergy analysis of a novel configuration containing reverse osmosis (RO), humidification-dehumidification (HDH) and flat plate collector (FPC) by considering the variations of chemical exergy, feed water mass flow rate, salinity and applied pressure have been presented. In the proposed configuration, the permeate and brine flows of two stand-alone HDH units have been combined with flows of RO-HDH system in order to reduce the brine and freshwater salinity as well as the number of elements used in each pressure vessel. The RO-HDH contains a single HDH which utilizes the RO brine water as intake to eliminate the need of pumping and pre-treatment in HDH unit and to increase freshwater production. The results indicate that utilization of the novel configuration increases the exergy efficiency of the desalination system up to 20.60%, while RO and HDH efficiencies are about 0.72% and 12.66% respectively. The amount of freshwater production has been increased to 5.76 m3/h and the brine and freshwater salinities have been reduced to less than 61,866 ppm and 534 ppm respectively. This new system configuration has shown promising advantages with respect to the separate RO and HDH systems in using high salinity feed water.