Exergy efficiency optimization for gas turbine based cogeneration systems

摘要

Energy degradation can be calculated by the quantification of entropy and loss of work andis a common approach in power plant performance analysis. Information about the location, amount and sources of system deficiencies are determined by the exergy analysis, which quantifies the exergy destruction.Micro-gas turbines are prime moversthat are ideally suited for cogeneration applications due to their flexibility in providing stable and reliable power. This paper presents an exergy analysisby means of anumerical simulation of a regenerative micro-gas turbine for cogeneration applications. The main objective is to studythe best configuration of each system component,considering the minimization of the system irreversibilities. Each component of the system was evaluatedconsidering the quantitative exergy balance.Subsequently the optimization procedure was applied to the mathematical model thatdescribes the fullsystem.The rate of irreversibility, efficiency and flaws are highlighted for each system component and for the whole system. The effect of turbine inlet temperature changeon plant exergy destructionwas also evaluated. The results disclose that considerable exergy destruction occurs in the combustion chamber. Also, itwas revealed that the exergyefficiency is expressively dependent on the changesofthe turbine inlet temperatureand increases with thelatter.