Assume we have a refrigerator operating at steady state using 500 W of

1.	Assume we have a refrigerator operating at steady state using 500 W of electric power with a COP of 2.5. What is the net effect on the kitchen air?
Answer» Take a C.V. around the whole kitchen. The only energy term that crosses the control surface is the work input W. apart from energy exchanged with the kitchen surroundings. That is the kitchen is being heated with a rate of W. Remark: The two heat transfer rates are both internal to the kitchen. Q. H goes into the kitchen air and Q. L actually leaks from the kitchen into the refrigerated space, which is the reason we need to drive it out again.

Assume we have a refrigerator operating at steady state using 500 W of electric power with a COP of 2.5. What is the net effect on the kitchen air?

Answer»

Take a C.V. around the whole kitchen. The only energy term that crosses the control surface is the work input W. apart from energy exchanged with the kitchen surroundings. That is the kitchen is being heated with a rate of W.

Remark: The two heat transfer rates are both internal to the kitchen. Q. H goes into the kitchen air and Q. L actually leaks from the kitchen into the refrigerated space, which is the reason we need to drive it out again.

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Assume we have a refrigerator operating at steady state using 500 W of electric power with a COP of 2.5. What is the net effect on the kitchen air?

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