  In this paper an analysis of the Stirling cycle in thermoeconomic terms is
developed using the entropy generation. In the thermoeconomic optimization of
an irreversible Stirling heat pump cycle the F function has been introduced to
evaluate the optimum for the higher and lower sources temperature ratio in the
cycle: this ratio represents the value which optimizes the cycle itself. The
variation of the function F is proportional to the variation of the entropy
generation, the maxima and minima of F has been evaluated in a previous paper
without giving the physical foundation of the method. We investigate the
groundwork of this approach: to study the upper and lower limits of F function
allows to determine the cycle stability and the optimization conditions. The
optimization consists in the best COP at the least cost. The principle of
maximum variation for the entropy generation becomes the analytic foundation of
the optimization method in the thermoeconomic analysis for an irreversible
Stirling heat pump cycle.
  Pacs: 89.65.G, 05.70 keywords: entropy generation, finite time
Thermodynamics, Stirling cycle, Thermodynamic optimization.
