This article presents a research project carried out by the Thermochemical Power Group of the University of Genoa and is concerned with the monitoring of a three pressure level heat recovery steam generator (HRSG).The work consists of the development of an original computer code usingMatlab software that calculates the performanceof heat exchangers, at differentpower plant operating conditions. This kind of software was developed with a twofold objective: to calculate the actual gas path inside the HRSG starting from the available measurements, thus obtaining the current effectiveness of all the heat exchangers in the HRSG, and to estimate the expected performance of each heat exchanger to be compared with the actual ones.Once the actual effectiveness and the expected effectiveness of the heat exchanger are defined,non-dimensional performance parameters suitable for degradation assessment can be defined. As a result of the sensitivity analysis, each performance parameter is coupled with an accuracy factor. The developed methodology has been successfully applied to historical logged data (3 years) of an existing large size (400MW) combined cycle, showing good capabilities in estimating the degradation of the HRSG throughout plant life.
