  The limit energy theorem which determines the possibility of transformation
the energy flow in power systems in the absence of technical work is
investigated and proved for such systems as gas lasers and plasmatrons,
chemical gas reactors, vortex tubes, gas-acoustic and other systems, as well as
a system of close stars. In the case of the same name ideal gas in the system
the maximum ratio of energy conversion effectiveness is linked to the Carnot
theorem, which in its turn is connected with the Nernst theorem. However,
numerical analyses show that the class of flow energy systems is non-carnot
one. The ratio of energy conversion effectiveness depends on the properties of
the working medium; a conventional cycle in open-circuit is essentially
irreversible. The proved theorem gives a more strongly worded II law of
thermodynamics for the selected class of flow energy systems. Implications for
astrophysical thermodynamic systems and the theory of a strong shock wave are
discussed.
