  Different economical configurations, due for instance to the relative cost of
the fuel it consumes, can push a heat engine into operating whether at maximum
efficiency or at maximum power produced. Any relevant design of such system
hence needs to be based, at least partly, on the knowledge of its specific
"power vs. efficiency" characteristic curve. However, even when a simple model
is used to describe the engine, obtained for example thanks to Finite
Dimensions Thermodynamics, such characteristic curve is often difficult to
obtain and takes an explicit form only for the simplest of these models. When
more realistic models are considered, including complex internal subsystems or
processes, an explicit expression for this curve is practically impossible to
obtain. In this paper, we propose to use the called Graham's scan algorithm in
order to directly obtain the power vs. efficiency curve of a realistic Stirling
engine model, which includes heat leakage, regenerator effectiveness, as well
as internal and external irreversibilities. Coupled with an adapted
optimization routine, this approach allows to design and optimize the same way
simple or complex heat engine models. Such method can then be useful during the
practical design task of any thermal power converter, almost regardless to its
own internal complexity.
