Question

A Carnot refrigerator extracts 150 kJ of heat per minute from space which is maintained at $-{23}^{\circ }C$ and is discharged to atmosphere at ${27}^{\circ }C$. The work required to run the compressor is

• A. 40 kJ/min
• B. 20 kJ/min
• C. 10 kJ/min
• D. 30 kJ/min

Answer 1

The correct option is D 30 kJ/min

$T_R=-23+273=250K,$

$T_o=27+273=300K$

$(COP{)}_{carsot}=\frac{T_R}{T_o-T_R}=\frac{250}{300-250}=5$

Now, RC = 150 kJ/min

$COP=\frac{RC}{P}$

$\Rightarrow P=\frac{150}{5}=30kJ/min$