Exergy and exergoeconomic assessment and multi-objective optimization of a renewable assisted CCHP system

Document Type : Original Article


1 Associate Professor, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran

2 Department of Renewable Energies and Environment Faculty of New Sciences & Technologies University of Tehran



The current study analyzed and optimized a renewable-assisted multi-generation system in energy, exergy, and exergoeconomic. The proposed system is composed of PTCs, a horizontal-axis wind turbine, an organic Rankine cycle, heat recovery heat exchangers, a parallel double-effect LiBr-H$_2$O absorptive chiller, heat recovery heat exchangers, and an electrolyzer. The designed system has been being used for the simultaneous production of electricity, heating, cooling, and hydrogen. Moreover, a thermodynamic model of the defined system has been developed in engineering Equation Solver (EES) software. A Genetic Algorithm (GA) model was also conducted to find the optimum composition of decision variables that efficiently optimize the system performance in terms of cost and exergy.  A sensitivity analysis also has been applied to measure the effect of decision variables on the exergoeconomic performance of the proposed system. Results show that rising the inlet flow rate and inlet flow temperature to the Organic Rankin Cycle (ORC) turbine has an upward effect on the system's exergy efficiency and production cost rate. In addition, it was found that the increase of the boiler pressure only increases the exergy efficiency to a certain degree, and the exergy efficiency of the proposed system reduces in the pressures above 2600 kPa. With the optimization of the decision variables using a GA model, it was found that there is room to enhance the exergy exploitation rate by 2.6% and reduce the total rate of the production cost of the proposed system by 12.9%.


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