Thermal stability analysis of nuclear and fossil fuel power plants including the Dulong-Petit heat transfer law and economic features

Abstract

The growing interest in leveling costs in electricity generation has led, on the one hand, to establish optimization criteria with economic parameters, and on the other, to study thermal stability for power plants models. In this work, a non-endoreversible heat engine model, as well as a non-linear heat transfer law (Dulong-Petit) are considered. Additionally, three performance regimes in the so-called profit function (aF) are analyzed: Maximum power output (P), maximum efficient power (Pη) and maximum generalized ecological function (E). By means of an approximate analytical expression for the efficiencies, we present local and global stability analysis for three different types of power plants (nuclear, combined-cycle and simple-cycle ones), including the most representative running costs (investment and fuel ones). We show that for less dissipative regimes (Pη and E), the disturbed internal temperatures return quickly to their respective steady states within the physical and economic intervals. This fact is best visualized by the direct Lyapunov method, i.e, there is no surface such that some steady state is globally asymptotically stable.