Energy and exergy analyses of a hybrid system integrating solar-driven organic Rankine cycle, multi-effect distillation, and reverse osmosis desalination systems

Abstract

This study analyzes the energy and exergy of a novel arrangement of a solar driven organic Rankine cycle (ORC), two reverse osmosis (RO) desalination systems, and a multi-effect distillation (MED) desalination unit. The ORC power is used as power sources of the high-pressure pump of the RO unit and pumping system of the MED unit. Also, the waste heat of the ORC condenser is utilized as the heat impetus of the MED unit. The results demonstrate that increasing the solar radiation intensity and collector module length leads to increase in the ORC power output, produced freshwater, and total exergy destruction. Increasing the volumetric flow rate of the collector reduces the temperature of the output fluid from the solar collector field, but the mass flow rate is increased, resulting in the highest net output power from the ORC system at a volume flow rate of 11000 lit/min. The exergy analysis reveals that the solar collector, as the system heat source, has the highest total exergy destruction share of 65% in the system. Also, among the organic fluids, toluene, n-decane, n-nonane and n-octane have the highest ORC power, the highest amount of produced freshwater, and the least exergy destruction for ORC, respectively.