Keywords: engineering thermodynamics, exergy theory, gravitational exergy component, gravity, exergy balance, atmospheric air, isothermal compressing
Influence of gravity on the exergy of substance
Due to buoyancy, the substance of the density different from that of the environment, presents the ability to work by lifting or sinking and, when achieving the density-equilibrium altitude, the physical, or even chemical, components of the substance exergy could change in results of the changed parameters of the local environments at the density equilibrium altitude. For a gaseous substance, proposed 'mechanical' exergy component is introduced. Considered is an exemplary simple process of a throttling of atmospheric air followed by its isothermal compressing. The exergy balance for the process is compared to the results obtained by the traditional method.