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For anyone interested in the history of this maximum power-efficiency relationship, it goes back to a book by Henri B. Reitlinger in 1929: Even if not so ancient, the history of the heat engine efficiency at maximum power expression has been yet turbulent. More than a decade after the publication of...

Adrian Bejan: Entropy generation minimization: The new thermodynamics of finite‐size devices and finite‐time processes. Entropy generation minimization (finite time thermodynamics, or thermodynamic optimization) is the method that combines into simple models the most basic concepts of heat transfer,...

I enjoyed the additional historical context around Carnot in the linked video. It tells us that following the invasion of France by the Germans, Ruskies and Prussians he puzzled out his ideal powerless reversible engine in an attempt to give his native France the upper hand in steam engine developme...

Temperature is a measure of the average kinetic energy of the particles in a sample of matter, expressed in terms of units or degrees designated on a standard scale. So, kinetic energy transferred to the thermometer bulb. But Joules are also representative of energy transfer. So this is all about en...

This more advanced analysis of heat engines takes into account the temperatures of the working fluid, because it accounts for the heat flux across the engine walls by considering 4 temperatures, rather than the two used by Carnot. https://tallsnaps.files.wordpress.com/2024/05/chambadal-novikov-buche...

Chambadal and Novikov published their work on this in the late 1950s. Not so much 'cherry picked' as 'up-to-date state of the art', back then. But they published in the Russian literature, which is likely why it didn't filter through to western physics until 1994. Better late than never. None powere...

I should have said Power output, not work. There is 'work done' internally in the Carnot cycle, but no power output. So this 'irreversible' Carnot cycle analysis is a step forward in relating thermodynamic theory to real world machines with a power output.

It should be noted that this 'irreversible' Carnot engine has real 'Work' output, whereas the old Carnot efficiency deals with an 'ideal' engine with no time dimension, and consequently, no 'Work done'. This is one of the effects of introducing the rate of heat flow into (and out of) the engine. It'...

A very nice geometrically demonstrated explanation of why the square root ends up in the equation is shown in this short and easy to understand paper by Manfred Bucher: This will especially interest Matt Brown I think. https://www.researchgate.net/publication/292805608_Maximum-power_efficiency_of_a_...

How does removing diatomic Oxygen (plus trace gases Argon, Carbon Dioxide etc), leaving only diatomic Nitrogen help, I wonder? Perhaps the main advantage has more to do with practical materials science than thermodynamics. Andy Ross had problems with flakes of iron oxide fouling one of his engines,...

Far from being too restrictive with his estimate of maximum efficiency for heat engines: η = 1 – (Tc / Th) Chambadal and Novikov say Carnot was being too generous. Their formulation is: η = 1 – √(Tc / Th) If you thought Carnot was saying you were going to get naff-all power out of your engine, these...

I came across two opposing theories. One says basically heat is a fluid and runs through a heat engine like water. The other says heat is energy and basically "disappears" inside the engine, as it is converted to work. If the latter is true, then it is really not necessary to design an en...

The average bulk temperature is what the engine reacts to. Any pressure sensors will react similarly to the engine, so it is a fair representation to use for analysis. The sensor will react as fast or faster than the engine. The theoretical pressure change due to volumetric change in an unheated en...

15Watts for $499. Plus $150 shipping.

petrol shill

What are you planning on firing your 15W generator with Tom? How much do you think it'll use?

Heh, no. Martin, the old rascal, has rubbished everyone elses efforts with some ropey test procedures, to try to get ahead of the curve. We're UK based, but collaborating with stateside companies too.