Nobody wrote: ↑Tue Jul 11, 2023 7:22 am
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Carnot law is a mathematical construct and provable only by mathematics. ...
LOL.... "Tom, I have concerns for your well being. ..." That's funny.
Your above statement regarding the Carnot "Law" I do not agree with.
The so-called law has a very definite (theoretical) basis in physical reality. It is the temperature difference, nothing more or less than that. It has both a physical (empirical) and a mathematical basis. As such it is subject to experimental testing.
If heat were actually a fluid, like water, in "reservoirs". One high and one low, I could see how in draining one reservoir into the other it might be "impossible" to utilize all the potential of the upper reservoir.
As the upper reservoir empties into the lower reservoir, the lower reservoir fills up higher, so the upper reservoir can "never" be drained completely.
So why should it not be possible to demonstrate such a physical reality by direct experiment?
Using actual water it is very easy to demonstrate at my kitchen sink with a couple glasses of water and some flexible tubing.
The atmosphere however, is a virtually infinite source or sink. If I have a finite heat source I should be able to "drain" that to the atmospheric sink 100% more or less, depending on the weather.
As interpreted and applied in academic courses on thermodynamics it is alleged that that is not possible and my finite heat resource can only be drained 20%
I can see how the conclusion is reached quite clearly because if you heat a mug of water in the microwave from ambient to boiling you have raised the temperature 20% (on the kelvin scale) so it can only be drained back down 20% Carnot efficiency is therefore 20% you cannot do any better than that.
That is a mathematical as well as an empirical reality.
Why do these academics make the assertion that you cannot have a "perfect" heat engine because it is impossible to reach absolute zero.???
If I run my heat engine on the glass of boiling hot water until "ALL" the heat is gone and the water is back at ambient, have I used ALL of that 20%???? it would seem so. Has the temperature of the water fallen to absolute zero? No.
IMO the Carnot limit REALLY meant, at some time in history that a heat engine could, at the absolute best, only utilize the heat available between the source and sink temperatures.
That is, if you heat the source up 10% on the kelvin scale, the engine cannot use more heat than what has been made available. Once that 10% has been used up the engine will stop, and because of friction, it will stop before that.
Perfectly reasonable.
But at some point some academic who did not really comprehend all this started teaching students this crazy idea that if you heat water up 10% on the absolute scale then only 10% of that 10% is available to run the engine and the other 90% of the heat used to boil the water has to be "rejected".
WHAT????
That's insane.
It's like saying if I give the bank $2 for change, the bank will only be able to give me back four cents in return, because two dollars is 2% of $100 so the exchange is limited to 2% and 2% of two dollars is 4 cents.
The Kelvin scale is like that 100% or $100 from which this exchange ratio is derived.
Now the "bank" is trying to tell me that the reason I can only get back four cents for my two dollars is, well, it's complicated and "can only be proven mathematically".