4E analysis of a modified multigeneration system designed for power, heating/cooling, and water desalination

Abstract

Multigeneration systems, owing to their efficient fuel utilization, are recognized as one of the best technical and economical methods of energy saving and climate control. In this paper, a multigeneration system is proposed for the production of power, heating/cooling, and desalinated water. The proposed system was first studied by means of an energy, exergy, exergoeconomic, and environmental analyses and the obtained results were compared with that of multigeneration systems described in the literature (the selected multigeneration systems are based on a gas turbine cycle as prime mover). In addition, a parametric study was used to investigate the effects of primary thermodynamic quantities such as air pre-heater outlet temperature, pinch-point temperature difference in evaporator, evaporator temperature of cooling cycle, and evaporator temperature of desalination system on cycle performance. Results indicated that the proposed cycle’s power, heating, cooling, and desalinated water production is 30.5 MW, 40.8 MW, 1 MW, and 0.364 kg/s, respectively. In addition, the cycle’s total cost and total CO2 emissions are 1943.5 $/h and 0.163 kg/kWh. The parametric survey showed that the air pre-heater outlet temperature and the gas turbine inlet temperature are the most influential parameters in changing the system’s CO2 emissions. In this way, an increase of the pre-heater outlet temperature causes a 26% reduction in the cycle’s CO2 emissions, whereas an increase of the gas turbine inlet temperature leads to a 53% increase in CO2 emissions.