Equation (17) also assumes a negligible difference in kinetic
energies of refrigerant at states 1 and 2.
If this is not the case,
a kinetic energy term must be added to the equation. All thermodynamic
properties discussed in this section are static properties as
opposed to stagnation properties; the latter includes kinetic energy.
The ratio of isentropic work to actual work is the adiabatic efficiency: