Exergo-economic analysis of a novel tri-generation system to produce power, heat and fresh water

The current study reviews the exergo-economic analysis of a new system for producing power, heat, and distilled water. This proposed system includes a gas turbine (GT) which its waste heat first was recovered by a heat recovery steam generator (HRSG) for producing saturated water vapor and then recycled by an organic Rankine cycle (ORC) for generating more power. Also, this system includes a geothermal energy resource for reheating organic fluid because of power and efficiency increase and a reverse osmosis (RO) desalination unit on the production of freshwater. Feed-water temperature is increased in the condenser via decreasing its mass flow rate. As a result, the unit cost of produced freshwater decreases by 32.24%. The exergo-economic factor of the system is 12.14%, suggesting that exergy destruction accounts for a high proportion of costs. GT/HRSG have the highest share in terms of the capital cost (86.10%). Finally, the effects of the pinch temperature difference in the HRSG and re-heating pressure on the unit cost of the power generated in the ORC, produced water vapor, distilled water, and the overall cost rate were investigated.