4E investigation of solar-driven RO and RRO osmotic desalination systems from water, energy, and environment relevance perspective: a comparative approach

Abstract

In this paper, two osmotic desalination systems, namely, plug reverse osmosis (RO) and recirculation reverse osmosis (RRO) systems integrated with solar and organic Rankine cycle (ORC), have been presented. These systems are modeled and optimized from energy, exergy, economic, and environmental perspectives. The objective functions are the concentration disposal index (CDI) and unit cost of the product (fresh water) (UPC). The results show that the RO cycle has an optimal configuration grounded on max (CDI) and min (UPC). At identical UPC, the environmental effects of the RO system were less than those of the RRO. This is attributed to higher recovery with increasing temperature of discharged water into the sea in a smaller area and at a higher rate. For the RO system, the values for CDI, exergy efficiency, and fresh water production are 0.193, 45.6%, and 13.1 m3/h for R245ca fluid. Also, the share of RO and RRO in the total TAC costs is 19.44% and 17.33%, respectively. The R245ca working fluid is selected for both cycles, which is more productive than the other fluids. The results show that more than 50% recovery is achieved for the SW30HR-320 membrane at the optimum for the RO system.