A heat engine operates between a source at TH and a sink at TC. Heat is supplied to the heat engine at a steady rate of 1200 kJ/min. Study the effects of TH and TC on the maximum power produced and the maximum cycle efficiency. For TC = 25oC, let TH vary from 300oC to 1000oC. Create plots of Wcycle and ηth as functions of TH. For TH = 550oC, let TC vary from 0oC to 50oC. Create plots of Wcycle and ηth as functions of TC. Discuss the results. Please note that there will be NO credit given for this problem if it is not solved with Excel.
6 Old Comments
4 comments:
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HINTS:
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* Be sure to check out the comments from Dr. B's course!
* You can assume that it is a Carnot heat engine.
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ANSWERS:
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(none)
do you have to treat the heat input different in this case as it is a rate? Can we just assume that the Wcycle is also a rate?
If we have to convert it how would we do that?
Dear anonymous,
Yes, since it is Qdot, you must use Wcycle_dot. Therefore, your thermal efficiency will be Wcycle_dot / QH_dot.
A common question through IM has been about the graphs. Please note that the X-axis should be the temperature, and the Y-axis should be BOTH Wmax_dot and the maximum thermal efficiency.
Since these Y-values are different orders of magnitude, you can either make two separate graphs or use the "Secondary Y-axis" feature in Excel.
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