Answer
a) $\dot{W}_s=73.06\ kW$
b) $\dot{V_1}=0.209\ m³/s$
Work Step by Step
From tables A-11 to A-13:
Inlet ($T_1=-24°C$, sat. vapor): $v_1=0.17398\ m³/kg,\ h_1=235.94\ kJ/kg$
Outlet ($P_2=0.8\ MPa, T_2=60°C$): $h_2=296.82\ kJ/kg$
From the energy balance, with negligible k.e. change:
$\dot{W}_s+\dot{m}h_1=\dot{m}h_2$
With $\dot{m}=1.2\ kg/s$
$\dot{W}_s=73.06\ kW$
The volume flowrate is given by:
$\dot{V_1}=\dot{m}v_1$
$\dot{V_1}=0.209\ m³/s$
