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Conduction

A manufacture...

Question

A manufacturer claims that its refrigerator has a COP of $1.4$ when cooling food at $7 C$ using ambient air at $23 C$ as a heat sink. Is this claim valid? $1$ for yes, $2$ for no.

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Solution

According to the first law, refrigerator COP definition, and thermodynamic temperature scale, $C O P_{m a x} = T_{l} / (T_{h} - T_{l}) = 280 / (296 - 280) = 17.5$ . Since the manufacturer's claim is less than this maximum COP, it is valid.

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