where
Q
is the sum of flows inlet heat,
W
flow of taken (obtained) work,
i
m
and
i
h
are the mass flow
rate and enthalpy of the individual flow substances. In Equation (1) as the form of the first law of
thermodynamics, the work is technical. This means that it is done by moving the fluid with respect to
the machine control volume, and not due to changes in volume of fluid that moves in relation to the
control volume. Accordingly, below is
tech
WW
. Now: