This sublibrary gathers cavities which volume is nonzero and which behavior is dynamic. Simple volumes, pressurizers, dynamic drum and steam dryer are available here.
For a better understanding of the underlying physics of volumes, see Chap. 14 of [EHB19].
Baligh El Hefni and Daniel Bouskela. Modeling and Simulation of Thermal Power Plants with ThermoSysPro. Springer, 2019.