If the only work done in a system is a change of volume at constant pressure, then the change in this quantity is exactly equal to the heat transferred to the system, leading it to sometimes be called "heat content" or "total heat".
This quantity is conserved as a constant in the throttling process, and it is often convenient to express the energy that can be extracted from a turbine in terms of the change in this quantity across the turbine. If the only work done in a system is a change of volume at constant pressure, then the change in this quantity is exactly equal to the heat transferred to the system, leading it to sometimes be called "heat content" or "total heat". The term that differentiates Gibbs free energy from Helmholtz free energy, FTP, what is this quantity symbolized H, defined as the product of pressure and volume added to a system's internal energy?
This quantity is conserved as a constant in the throttling process, and it is often convenient to express the energy that can be extracted from a turbine in terms of the change in this quantity across the turbine.
enthalpy