It would be convenient to have a similar equation for isobaric processes.

The compressed air then runs through a mixing chamber where fuel is added, an isobaric process.

Its thermodynamic conjugate, an isobaric process would appear as a straight horizontal line.

An isobaric process occurs at constant pressure.

In an isobaric process, the pressure remains constant, so the heat interaction is the change in enthalpy.

Similarly, an isobaric process may trace a hyperbola in the quadrant of absolute temperature and gas density.

The index denotes an isobaric process.

It is also the same as an Ericsson cycle with the isobaric processes substituted for constant volume processes.

An isobaric process is shown on a P-V diagram as a straight horizontal line, connecting the initial and final thermostatic states.

In an isobaric process, the volumetric thermal expansivity, which we denote , is given by the ideal gas law:

Note that one may discuss isobaric surfaces or isobaric processes; likewise one may discuss isothermal surfaces or isothermal processes.

The isentropic processes are impermeable to heat: heat flows into the loop through the left expanding isobaric process and some of it flows back out through the right depressurizing process, and the heat that remains does the work.