Answer
a) $28390$ $kJ$
b) $1936.9$ $kJ$
Work Step by Step
All the symbols have the usual meaning.
$T_C=0 \hspace{1mm}{}^oC=273.15K$
$T_H=24 \hspace{1mm}{}^oC=293.15K$
$K_{carnot}=\dfrac{T_H}{T_H-T_C}= 14.6575$
Latent heat of fusion for ice $=334$ $kJ/kg$
Let $W$ be the energy supplied to the device.
a) Mass of water $=85$ $kg$
Heat discharged to the room $Q=(85\times 334)$ $kJ=28390$ $kJ$
b) $K_{carnot}=\dfrac{Q}{W}=14.6575$
$\Longrightarrow W=\dfrac{28390}{14.6575}\hspace{1mm}kJ\simeq 1936.9$ $kJ$
