Question

The temperature inside a Carnot refrigerator placed in a kitchen at 22 degree Celcius is 2 degree Celcius. The heat extracted from the refrigerator is 89 MJ/h. What power is needed to operate this refrigerator?

Answer 1

Answer: 1.79 kW

Step-by-step explanation:

Given

The temperature of the refrigerator is
`T_L=2^(\circ)C\approx 275\ K`

The temperature of the kitchen is
`T_H=22^(\circ)C`

COP of the refrigerator is

`COP=(T_L)/(T_H-T_L)=\frac{\text{Desired effect}}{\text{Power}}\\\\\Rightarrow COP=(275)/(22-2)=(89)/(P)\\\\\Rightarrow P=(20)/(275)* 89=6.47\ MJ/h\ \text{or}\ 1.79\ kW`