Answer
$w_e = 3.27\ kW$
Work Step by Step
The energy balance for this system reduces to:
$-W_e=\Delta U=mc_v\Delta T$
For an ideal gas:
$PV=mRT$
Plugging in the values $P_1=100kPa, T_1=5°C=278.15K,V=120m³, R=0.2870\ kJ/kg.K$
We get $m=150.32\ kg$
With the values of $c_v=0.718\ kJ/kg.K, \Delta T=20 K$
We derive $-W_e=2158.61\ kJ=-w_e\Delta t$
Since $\Delta t = 11min = 660 s $
$w_e = 3.27\ kW$
