Simulation and exergy-economic optimization of a trigeneration system

In this study, a combination of micro gas turbine, absorption cooling, and organic rankine cycle is selected. The system is modeled applying the laws of thermodynamic, and based on this model, exergy and economic analyses are performed for each component of the system. Four design variables, namely compressor pressure ratio, turbine inlet temperature, turbine efficiency, and compressor efficiency are considered to evaluate the system performance. Two models have been used and compared to assess the effect of chemical exergy on irreversibility of absorption cycle once regardless of chemical exergy effect and then with the consideration of chemical exergy effect on the system analysis. Exergy efficiency and total cost rate are considered as two objective functions of the tri-generation system. Based on these findings, the exergy efficiency, by promoting micro gas turbine cycle to a tri-generation system, increases from 31% up to 38.6%. The findings, based on Pareto front, indicate that exergy efficiency can be increased up to 52%, and the total cost rate can be reduced to 5.2 $/hr.