Chapter 6 - The Second Law of Thermodynamics - Problems - Page 325: 6-147

$C=\$0.123$

$\dot{m}=\frac{P\dot{V}}{RT}$ $P=92\ kPa,\ \dot{V}=560\ m³/h,\ R=0.287\ kJ/kg.°C,\ T=22°C$ $\dot{m}=0.169\ kg/s$ $\dot{Q}=\dot{m}c_p\Delta T,\quad c_p=1.0\ kJ/kg.°C,\ \Delta T=(22-5)°C$ $\dot{Q}=2.874\ kW$ $F=\dot{Q}\Delta t/\eta,\ \eta=0.96,\ \Delta t=1\ h$ $F=2.994\ kWh$ $C=F\times p_f,\ p_f=\$1.20/therm$ $C=\$0.123$