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Problem 21.8: Refrigerator and entropy
Please wait for the animation to completely load.
There is a time delay-since the system must be in equilibrium-before the initial change of state occurs.
You must go in order.
In this animation N = nR (i.e., kB = 1). This, then, gives the ideal gas law as PV = NT. Assume an ideal gas. Restart.
The reverse of an engine is a refrigerator. An engine uses heat to produce work, while a refrigerator does negative work on the gas (something else does work on the gas) to remove heat. The coefficient of performance is K = |QC|/|W| (heat transferred out of the cold reservoir divided by the work required)
- In which step is the heat removed from the cold reservoir (i.e., heat removed from the refrigerator and absorbed by the gas)?
- In which step is work done on the gas?
- For the refrigerator, find the work done during each cycle, the heat transferred from the cold reservoir, and the coefficient of performance.
- What is the change in entropy for the complete cycle?
Problem authored by Anne J. Cox.