An advanced exergy analysis based on the dysfunction and malfunction methodology for a combined cycle power plant: a Mexican case study

The present work studies the irreversibilities and inefficiencies of a combined power plant. The analysis predicts the malfunction and dysfunction distributions for a typical system located in Mexico. The study was conducted by first performing the energy balances of the system using the first law of thermodynamics. The concept of exergetic unit cost was then used to calculate the corresponding exergy destruction of the plant. And finally, structural theory and symbolic thermoeconomic analysis for constructing the malfunction and dysfunction conditions of the plant, showing clearly that for the combined cycle the irreversibilities are basically increased through the dysfunctions. The previous analysis shows the following results: the total increment of the irreversibility for the present cycle is 19879.33 kW, which represents about 3.5% of the fuel exergy required taking into account data of design; and the subsystems with the greatest dysfunctions correspond to both gas compressors.