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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?

Respuesta :

Answer: 1.79 kW

Explanation:

Given

The temperature of the refrigerator is [tex]T_L=2^{\circ}C\approx 275\ K[/tex]

The temperature of the kitchen is [tex]T_H=22^{\circ}C[/tex]

COP of the refrigerator is

[tex]COP=\dfrac{T_L}{T_H-T_L}=\dfrac{\text{Desired effect}}{\text{Power}}\\\\\Rightarrow COP=\dfrac{275}{22-2}=\dfrac{89}{P}\\\\\Rightarrow P=\dfrac{20}{275}\times 89=6.47\ MJ/h\ \text{or}\ 1.79\ kW[/tex]

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