Answer
a) $\dot{Q}=95,130\ kJ/h$
b) $\dot{V}=8185\ m^3/h$
c) $\dot{W}=22.02\ kW$
Work Step by Step
For the breads:
$\dot{m}=1200\ breads/h \times 0.350\ kg/bread=420\ kg/h=0.1167\ kg/s$
$\dot{Q}_s=\dot{m}c_p\Delta T,\ c_p=2.93\ kJ/kg.°C,\ \Delta T=(30-(-10))°C$
$\dot{Q}_s=49,224\ kJ/h$
$\dot{Q}_l=\dot{m}\Delta h_f,\ \Delta h_f=109.3\ kJ/kg$
$\dot{Q}_l=45,906\ kJ/h$
$\dot{Q}=\dot{Q}_s+\dot{Q}_l=95,130\ kJ/h$
For the air:
$\dot{Q}=\dot{m}c_p \Delta T,\ c_p=1.0\ kJ/kg.°C,\ \Delta T=8°C$
$\dot{m}=11,891\ kg/h$
$\dot{m}=\frac{P\dot{V}}{RT},\quad P=101.3\ kPa,\ R=0.287\ kJ/kg°C,\ T=-30°C$
$\dot{V}=8185\ m^3/h$
$COP=\dot{Q}/\dot{W}=1.2$
$\dot{W}=79275\ kJ/h=22.02\ kW$
