FIRST LAW OF THERMODYNAMICS
The control volume approach is one in which a fixed region in space is established with specified
control boundaries, as shown in Figure 15. The energies that cross the boundary of this control
volume, including those with the mass crossing the boundary, are then studied and the balance
performed. The control volume approach is usually used today in analyzing thermodynamic
systems. It is more convenient and requires much less work in keeping track of the energy
balances. Examples of control volume applications are included in Figures 16-18.
Figure 16 Open System Control Volumes