Thermodynamic, economic, and environmental evaluation of internal combustion engine exhaust gas-driven Organic Rankine cycles for power generation and desalination

The conversion of waste heat into power is important due to the diminishing reserviors of fossil fuel and the rise in environmental pollution. The recovery of waste heat from internal combustion (IC) engines through the Organic Rankine Cycle (ORC) presents a practical approach to improving overall performance, attributable to the simple design of the ORC system. This study examines the energy, exergy, economic, and environmental aspects of IC engine waste heat-driven basic and regenerative configurations of the Organic Rankine cycle. The chosen configurations of ORCs are combined with reverse osmosis (RO) units to produce freshwater. The ORCs use R245fa as the working fluid. The results indicate that the maximum net power output, energy efficiency, exergy efficiency, rate of exergy destruction, working fluid mass flow rate, and distillateflow rate obtained from the basic ORC(BORC) were :195.9 kW, 14.68 %, 19.65 %, 732.7 kW, 5.499 kg/s, and 19.74 m³/h, respectively. Moreover, the maximum net power output, energy efficiency, energy and exergy efficiencies, rate of exergy destruction, working fluid mass flow rate, and distillate flow rate obtained from theregenerative ORC(RORC) were evaluated as 200.9 kW, 15.06 %, 20.16, 730.3 kW, 5.642 kg/s, and 20.21 m³/h, respectively. The optimal payback period is indicated by BORC, calculated to be 2.87 years. The RORC demonstrates enhanced sustainability. The maximum sustainability index determined was 1.34 for RORC. The parametric analysis reveals that increasing turbine inlet pressure (TIP) is evaluated to enhance system performance. However, increase in Condenser Pressure (CP) negatively impacts system performance. RORC's performance surpasses BORC's, owing to its regenerative capabilities.