University Humor
I went to a prestigious University, let's just say it rhymes with "Nice University". Has a well-respected science and engineering staff. They teach the same thermodynamics mythology as every other university, so this isn't picking on "Nice University", it just happens I went there.
One of the Thermodynamics professors had a sign as if it was a business, "Carnot Cycle Engines made here, the only reversible engines, most efficient engines", or some such. Paraphrased of course, my memory starts leaking after a few decades.
Point being, "Nerd Humor". Ha-ha this is funny but if you don't know about thermodynamics you won't get it. Because you don't know this cycle is special and can't be made. So, we laugh at you for your ignorance.
But what's really funny is how the Universe is laughing at every thermodynamics professor, who doesn't get it, because the joking Nerd's have a fundamental misunderstanding of the Universe. Nerd's finally at the butt end of their own Nerd jokes.
Why? Because all engine cycles are reversible (well, at least as reversible as the Carnot Cycle). Sadi Carnot and Lord Kelvin in "Reflections" clearly understood that. Will come back to that in chapter "Reversibility".
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The myth about Carnot Cycle
Every Physics student gets thermodynamics at some point, and when it comes to heat engines, we get the Carnot Cycle Story.
It goes like this: Carnot created an engine cycle, (now called the Carnot cycle). That part is true.
Its impossible to build one. It is optimal because its reversible. All engine cycles it is possible to build are less good at converting heat to work. You know its reversible because you can run the cycle in reverse. And when the cycle is run backwards, it does refrigeration. Only reversible cycles can do refrigeration. The Carnot Ratio is the solution to the amount of energy conversion done by the Carnot Cycle. Other engine cycles get a ratio less than the Carnot Ratio.
I fell for it. Well maybe didn't get it, but I definitely knew what they wanted on the test.
Did I mention I learned this in an air condition room?
Lets think about that, link the bits together. Its the only cycle that can run backwards, and only cycles that can run backwards can refrigerate, and its impossible to build. So there are no cycles that are actually possible to build that refrigerate. These "facts" learned in air conditioned room.
The human mind has a near infinite capacity to believe self-contradictory things.
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