The TRUTH? η = 1 – (Qc / Qh) = 1 – (Tc / Th)

[VincentG]

In other words, the only free return stroke is at zero Kelvin.

Simply not true, Senft called this constant mechanical effectiveness, and it is possible at ambient temperature.

[Fool]

With a lower power to weight ratio, the engine will be trying to overcome a bigger heavier mechanism with higher friction bearings, plus a higher back work, with the same or lower production of power. The back work, P•Delta V, is the main problem.

The Stirling engine only scavenges the residual heat after the constant temperature expansion. It is the same energy that the Carnot Cycle would scavenge using adiabatic expansion and work. The Stirling does it with a displacer and regenerator combination.

[VincentG]

In other words, the only free return stroke is at zero Kelvin.

Simply not true, Senft called this constant mechanical effectiveness, and it is possible at ambient temperature.

In fact, I had assembled such an engine that had constant mechanical effectiveness.

[Fool]

In other words, the only free return stroke is at zero Kelvin.

Simply not true, Senft called this constant mechanical effectiveness, and it is possible at ambient temperature.

Back work is not overcome by effectiveness. Effectiveness is negative on the power stroke, and positive on the return stroke, for a net gain of zero. The reason it is overlooked on the expansion stroke is that it is smaller than the energy developed by the internal gas pressure on that stroke. So the power stroke will be a net gain, and so will the return stroke. Since the return stroke is fighting against the recompression it will be a much much smaller work gain.

Even though it looks like a win win situation, it's not. It has the same work out, and same heat in, for the same efficiency.

In other words, the energy gained per cycle, will still be only the amount of area inside the cycles PV diagram loop. It doesn't change with a change in buffer pressure. All other things being equal.

There would be leakage past the seals and rings that would increase the mass of the working gas, if you're inclined to test it. That doesn't count because it is a different factor.

Constant effectiveness does allow a reduced flywheel inertia.

[VincentG]

There is no recompression of the gas with the right volume ratios. It's net power from BDC all the way through TDC, then TDC all the way to BDC. The only backward is from friction/moving the displacer, not thermodynamic.

[Tom Booth]

Qcz is not rejected during the running. Nor is it added. It is the base energy that DQh is added to. Earlier definition discarded.
....

Right.

In the face of shifting definitions, slippery as an eel, trying to pin anything down to have any rational conversation is impossible.

At this point I think it has been shown conclusively your original analysis, definitions, values, equations etc, were flawed.

I'm not wasting any more time on trying to hammer out the dents.I'm calling it totaled. Call the insurance company. Get a new model.

Anyway, I've run out of time to spend on this exercise and have other things to do.

[Fool]

VincentG, what you are replacing compression with, is heat rejection.

The buffer pressure still causes reduced work one way, and increased in the other, for a total of zero net help. It's adiabatic bounce.

Qcz is the same. The efficiency is the same.

A good test for it would be to run it in a vacuum. Zero buffer pressure. It will possibly still run, and if does, it will get the same efficiency. The indicator area will not change. Gas leakage out and flywheel size would be potential downfalls.

[Fool]

Tom I'm sorry you feel that way. I really haven't changed the derivation or definition. What I'm striving to do now is hammar out the explanations. Thanks for trying. I will redo it all and repost so it will be cohesive.

[Fool]

VincentG,

The real test would be to get any engine without a crankshaft, or spring, or buffer pressure, or double acting piston and cylinder, to run in a vacuum. The cylinder will become a gun barrel every time spitting the piston out the one end. That will happen regardless of the pressure in the cylinder, or whether it is heated or cooled. There is no such thing as contraction in gas or liquid. Only solids can produce a pulling force, like springs.

Liquids can reduce in size, but they turn to gas in the space of a vacuum and it is the outside pressure that causes the volume to decrease.

In liquid systems engineers call it cavitation, boiling of the liquid from too low a pressure. Hydraulic systems never work on suction. At least not well.

Gasses expand to fill their container. This is called pressure. Cooling them, heat rejection or addition, doesn't cause volume change, it only reduces pressure, or increases it. The volume change has to come from outside, either mechanical force, or a higher outside pressure, or lower. We just view it from different perspectives/pressures.

[VincentG]

VincentG, what you are replacing compression with, is heat rejection.

Yes.

The buffer pressure still causes reduced work one way, and increased in the other, for a total of zero net help. It's adiabatic bounce.

Ok.

A good test for it would be to run it in a vacuum. Zero buffer pressure. It will possibly still run, and if does, it will get the same efficiency. The indicator area will not change.

If this is all the case, then why consider atmospheric buffer pressure as a detriment to efficiency at all? Isn't that the basis of the equation, that a higher temperature delta results in higher efficiency?

And if we can eliminate atm. buffer pressure as a consideration, then why is our base temperature of 300k(instead of absolute 0) a hinderance to efficiency?

[Tom Booth]

Tom I'm sorry you feel that way. I really haven't changed the derivation or definition. What I'm striving to do now is hammar out the explanations. Thanks for trying. I will redo it all and repost so it will be cohesive.

OK, if you say so. Looking forward to that.

But, really, for the most part, your "definitions" and general presentation has been no different, or not much different, than the, (nothing personal) nonsense I've been going over again and again, backwards and forward for the past, at least 15 years.

What I'm pointing out as apparent contradictions or illogical, impossible scenarios or "magic" variables and so forth is nothing I haven't seen before.

Personally I think the Carnot efficiency mathematics originated with the steam engine, is applicable to steam, but not really valid when applied to Stirling hot air engines that do not "transport" any "latent heat" into, through and out of the engine.

It maybe could work out IF heat were ACTUALLY a fluid, a substance with actual mass that somehow could penetrate iron and steel (the "caloric" concept of heat) but, apparently that is not the case.

The only thing entering a Stirling engine is energy. Energy in one of its purest forms.

That energy is susceptible to conversion into other forms of energy with a very high conversion efficiency, like any other form of energy. So the 2nd Law that treats heat as in some way "special" and subject to some very strict, and unreasonable "limit" is utter nonsense resulting from trying to apply a mathematics derived from the steam engine, with mass flow to external combustion engines with no mass flow.

Many Stirling engines are hermetically sealed. No mass flow whatsoever being possible. The math used for steam engines doesn't add up when applied to Stirling engines.

The way the Carnot "efficiency" is being calculated and interpreted is nonsense.

It is NOTHING but the temperature difference.

Temperature has nothing to do with the QUANTITY of heat or efficiency.

All it is is the amount of "fuel" available.

[matt brown]

In other words, the only free return stroke is at zero Kelvin.

Simply not true, Senft called this constant mechanical effectiveness, and it is possible at ambient temperature.

Back work is not overcome by effectiveness. Effectiveness is negative on the power stroke, and positive on the return stroke, for a net gain of zero. The reason it is overlooked on the expansion stroke is that it is smaller than the energy developed by the internal gas pressure on that stroke. So the power stroke will be a net gain, and so will the return stroke. Since the return stroke is fighting against the recompression it will be a much much smaller work gain.

Even though it looks like a win win situation, it's not. It has the same work out, and same heat in, for the same efficiency.

In other words, the energy gained per cycle, will still be only the amount of area inside the cycles PV diagram loop. It doesn't change with a change in buffer pressure. All other things being equal.

There would be leakage past the seals and rings that would increase the mass of the working gas, if you're inclined to test it. That doesn't count because it is a different factor.

Constant effectiveness does allow a reduced flywheel inertia.

Kudos, Fool, xlnt response, short and sweet while devoid of any math distractions.

Common LTD with apparent 'cold stroke' during compression process tax 'hot stroke' during expansion aka no free lunch. Thus, as Fool says, Wnet per CYCLE is constant, whereby Wpos vs Wneg per PROCESS (think location) vary by charge vs buffer pressure. If you game various PVT values, you'll discover how limited this 'cold stroke' illusion is (ambient pressure akin flywheel moving energy between processes). I'm clueless what Senft meant by "mechanical effectiveness" unless he was trying to nix 'useless' flywheel.

[matt brown]

The way the Carnot "efficiency" is being calculated and interpreted is nonsense.

It is NOTHING but the temperature difference.

Temperature has nothing to do with the QUANTITY of heat or efficiency.

All it is is the amount of "fuel" available.

I'll willing to go along with Carnot buzz under certain conditions where I'd describe Carnot as a coincidence. However, Fool is trying to convince us Carnot is a consequence by qualifying energy into temperature whereby Carnot can be quantified via temperature. Indeed, a slippery slope which I also consider 'slight of hand'...

[Goofy]

@Fool,
Quote :
" we may assume that thermodynamic language has to change in the future to be more aligned with the real empirical phenomena and, even more, according to the causality of the underlying phenomena.
Article “Thermodynamics: A Misconceived Theory” (Hans Fuchs 1987)
Quote
Children and physicists alike conceive of heat as being contained in physical systems, even though the “heat” of the physicists’ thermodynamics does not allow for this interpretation. In my opinion, the misconception does not lie with the children but with the particular structure of the theory of thermodynamics. Rather than exorcizing basically sound ideas, I prefer to construct a new approach to teaching thermodynamics based on the notion of heat acquired in everyday life (which is rendered formal by a modern version of the caloric theory of heat). On the basis of didactic considerations we should reject any theory of heat which does not allow for heat to be contained in bodies.
Unquote
Source: https://www.researchgate.net/publicatio ... ved_Theory
1. "Can Second law of Thermodynamics be abandoned?"
Sure, it is possible to work out a valid, powerful and fruitful physical theory without even mentioning this basic law explicitly - though using its implicit, and throughout valid representation, in combination with metaphysics - and a sheer voluntarism.
The powerful proof of the above statement: Quantum Mechanics - based upon the so-called Equilibrium Thermodynamics and Equilibrium Statistical Mechanics.
In this sense, my answer ought to be largely positive.
2. "Wouldn’t it be an interesting idea to explore the possibility that the troubled second law of thermodynamics can be cancelled, completely?"
My answer is:
IMHO, it is not interesting to explore anything, which is clearly impossible to 100% - even at a prevenient look...
The basic fundamental content expressed by what you are dubbing "the troubled second law of thermodynamics" MUST ANYHOW be present in any realistic physical theory - here I intentionally choose the modal verb MUST.
The actual "TROUBLE" of the law we are discussing here is that the ENERGY TRANSFORMATION is NOT A SEPARATE LAW, it is but an integral part of the TRUE - BASIC - FUNDAMENTAL - NATURAL - LAW:
'The Law of Energy Conservation and Transformation'.
The Total Energy Conservation is a QUANTITATIVE aspect of the Energy notion.
The mutual Transformation of all the Energy types/forms available/imaginable is a QUALITATIVE aspect of the Energy notion.
What is the actual seminal achievement by N. L. S. Carnot, who could cause us to think over the modalities of the Energy types/forms transformation among each other?
The problem he had posed was to prove that Perpetuum Mobile is never possible.
To prove this, he had suggested a theoretical gadget we now know as the Carnot Cycle: It is an idealistic machine with the cyclic working modus, which is designed to convert the Heat into the Mechanical Work, with latter being a USEFUL ENERGY form.
Why Carnot's machine is idealistic?
Because it has no obvious hindrances/obstacles/resistances likewise friction - or similar - it is thus both a THEORETICAL and an IDEALLY ENGINEERED DEVICE.
The actual particular nature of the working material is also not important: It might even be an ideal gas, which is, however, nothing more and nothing less than just a purely mathematical tool to facilitate theoretical analyses. That realistic gases may be partially describable in the ideal gas terms does facilitate engineering efforts.
With all this in mind, what is then the very result by Carnot?
The maximum efficiency of such an IDEAL process to transform a Heat portion into a Work portion is about 25%, whereas we know that if, in reality, we perform a Work portion, the latter will to 100% go over into the Heat (plus we get wear of the working device and materials).
This is why, Heat ought to be the LEAST USEFUL FORM of ENERGY ever known!
Clausius had no time and impulse to realize the actual significance of Carnot's result - although Clausius might still go a truly seminal step toward understanding Carnot's result.
Indeed, what might lie behind the minimum efficiency when we transform the Heat into Work (SIC! - but never vice versa - SIC!)?
Apart from apparent hindrances/obstacles/resistances there are also INTRINSIC ones.
Clausius could introduce the notion to conclusively substantiate the INTRINSIC hindrances/obstacles/resistances under study in terms of the Energy notion: That was just the Entropy notion.
Indeed, Isaac Newton had formulated the Basic Fundamental Mechanical Law we now know as the Third Law of Newton:
Any Action cases the proportional Reaction.
This way, we know now that the more Action, the more Reaction; Zero Action ought to cause Zero Reaction.
Thus, the principal contribution by Clausius, Lord Kelvin and their colleagues was to clarify that Reaction must somehow reach its Maximum Value, so that, if we do have the Driving Force enough, to OVERCOME the MAXIMUM of all the ubiquitous hindrances/obstacles/resistances - to equilibrate, to compensate the latter - then the AIM of the process we are heading for would be REACHABLE at such a cost...
This is just what is in effect behind the Entropy notion.
I hope it is clear that any valid physical/chemical/biological/etc./etc. theory does require a true Entropy notion (either IMPLICITLY or - even better! - EXPLICITLY)...
3. "Maxwells' demon" is a non-scientific emotion. To try digging some science out of it might come for two reason's:
1. Overwhelming emotions, which might retract from doing scientific research...
2. Particular anti-scientific plans, which might kill scientific research in its roots...
4. "CLAUSIUS THEOREM": It is largely underestimated in fact. It is indispensable - especially when treating the Entropy notion EXPLICITLY.
5. "Maybe the second law of thermodynamics is a construct which can't possibly being aligned to physics at all? Simply because it tries to capture phenomena which can't be captured by the constructed idea (methodology) behind the present second law of thermodynamics?"
We should stop trying to separate the Head from the Tail of a truly golden coin:
'The Law of Energy Conservation and Transformation'
- in cutting out the Energy Conservation from the Energy Transformation...
If the coin is intact it is to 100% functional, if not - we need further efforts to provide for the coin's functionality. Well, per se, such an approach ought to be 100% OK, just what Quantum Mechanics' history and fruits do prove... However, absolutizing such approaches might have truly pathological consequences, for the scientific research per se...
The methodology behind the present handbook version of the 'second law of thermodynamics' is exceedingly simple: To separate the coin's head from the coin's tail...
Is this a constructive approach? I guess the poser is largely rhetoric...
6. "If this idea is being explored then one has the cognitive freedom to observe irreversible phenomena from the widest possible perspective."
Our Mother Nature has NO REVERSIBLE phenomena.
REVERSIBLE is only the idealistic theoretical cyclic gadget by N. L. S. Carnot.
Trying to seriously discuss any kind of REVERSIBLE PHENOMENA is nothing more and nothing less than simply to PHYSICALIZE the ingenious model by Carnot, just to produce a phantom PERPETUUM MOBILE with the respective properties, which might never be localized experimentally (either implicitly or explicitly).
In addition to the latter, do render Four Basic Laws out of a Unique Basic Law, do cause overall excitement around some magic Probability of (the God knows what scilicet) - or not less magic Information about the God knows what scilicet... This would give you valid, valuable and seminal theoretical tool as a result of a skillful mathematical exercise...
...A truly different approach: To properly consider coupling between Driving Forces and Entropy (the sum of the pertinent ubiquitous Reactions) may finally deliver the widest possible perspective to observe the irreversible phenomena.
Respectfully yours,
Evgeni Starikov
Fantasy formula
I used the word “fantasy” because it basically expresses the quality of Clausius and Carnot theorems; both are purely empirical without any link to real-life phenomena; there is no single phenomenological explanation. And certainly when one also includes the fact that pressure, temperature, energy and entropy are entities which do not exist in reality; they were invented by humans according to our inherent way of perception of the macroscopic reality. This expression is partly quoted from Ilya M. Peshkov and Evgeniy Romenski
Article “A hyperbolic model for viscous Newtonian flows”
Quote
1.2 Navier-Stokes equations and hyperbolicity
[…] We shall refer to such a mimic strategy as the response modeling (RM) approach. The RM approach is inherently an observer-dependent strategy, i.e., subjective. For example, typical state variables in a model developed in the framework of the RM approach are either the pressure p, temperature T, or total stresses T , etc. However, it is clear that these entities do not exist in reality; they were invented by humans according to our inherent way of perception of the macroscopic reality by means of some interpretative procedures of microscopic processes, not to be confused with an averaging. […]
Unquote
Source: https://www.researchgate.net/publicatio ... nian_flows)
In my opinion, fundamental interactions differ from that; even though they are basically also empirical phenomena, they have a solid elementary analytical explanation and foundation. Maybe “fantasy” is not a good expression because both formulas (Carnot and Clausius) comply with the observed phenomena.
The word “fantasy” formula can only be used properly for a formula like, for example, Q heat flow [W] = U x A x (T2-T1) in which the heat flow has the direction from matter with a high measured temperature to matter with lower measured temperature. This formula can be considered as a “fantasy” formula because there are no reasons to assume this formula will ever lead to a phenomenological explanation.
So I do withdraw my comments in which I used the word “fantasy“ formula for the Carnot and Clausius formulas.
For the Carnot and Clausius formula the word “curve fit” would have been better;
curve fit: find an arithmetic formula which complies with the phenomenological observations
Similar to the great function “Trendline” in Excel. And similar like the way scientists developed a hyperbolic formula for relativistic heat conduction; in my opinion without an phenomenological explanation this should be presented as work in progress which may lead to a final analytical explanation on a certain physical level using things like atoms, molecules, radiation, etc. Until that, one should be careful calling it science.
As an example of being not a complete phenomenological explanation I refer to the so-called “upgrade” of the parabolic Fourier equation to a hyperbolic form, which in my opinion is a curve fit and should be further researched to ultimately find an associated complete phenomenological explanation.
Quote
Hyperbolic model
It is well known that the Fourier equation (and the more general Fick's law of diffusion) is incompatible with the theory of relativity for at least one reason: it admits infinite speed of propagation of heat signals within the continuum field. For example, consider a pulse of heat at the origin; then according to Fourier equation, it is felt (i.e. temperature changes) at any distant point, instantaneously. The speed of information propagation is faster than the speed of light in vacuum, which is inadmissible within the framework of relativity.
To overcome this contradiction, workers such as Cattaneo, Vernotte, Chester, and others proposed that Fourier equation should be upgraded from the parabolic to a hyperbolic form,
Unquote
Source: https://en.wikipedia.org/wiki/Relativis ... conduction
Can the Second law of thermodynamics be abandoned?
I speak for myself; I don't have any personal problems nor feelings by abandoning the second law of thermodynamics; I don’t disrespect Carnot, Clausius, nor any other person in the world; good or bad. For me they are the same heroes as any retired scientist or high school teacher without any scientific reward or legacy. And be honest; we have forgotten to honor many thermodynamic heroes according this book of Evgeni B Starikov:
Book “A Different Thermodynamics and Its True Heroes”
Quote
The book presents the life stories of the protagonists in detail and allows readers to cast a look at the whole scene of the field by showcasing a significant number of their colleagues whose works have fittingly complemented their achievements. It also tries to trigger a detailed analysis of the reasons why the actual work in this extremely important field has in effect gone astray. It comprises five chapters and introduces three scientists in the first two chapters, which are specifically devoted to the Scandinavian achievements in macroscopic thermodynamics. These introductions are novel and call for a detailed reconsideration of the field. The third chapter acquaints the readers with their fourth colleague in Germany who was working on the proper link between the macroscopic thermodynamics, kinetics, and the atomistic representation of matter. The fourth chapter brings in their fifth colleague in the United States who could formally infer the famous formula S = k * ln(W), ingeniously guessed by Ludwig Boltzmann, and thus clarify the physical sense of the entropy notion.
Unquote

[matt brown]

VincentG, what you are replacing compression with, is heat rejection.

Yes.

The buffer pressure still causes reduced work one way, and increased in the other, for a total of zero net help. It's adiabatic bounce.

Ok.

A good test for it would be to run it in a vacuum. Zero buffer pressure. It will possibly still run, and if does, it will get the same efficiency. The indicator area will not change.

If this is all the case, then why consider atmospheric buffer pressure as a detriment to efficiency at all? Isn't that the basis of the equation, that a higher temperature delta results in higher efficiency?

And if we can eliminate atm. buffer pressure as a consideration, then why is our base temperature of 300k(instead of absolute 0) a hinderance to efficiency?

Apples and oranges...the system vs surroundings pressure differential (charge vs buffer) effects work per process (expansion vs compression) while the system vs surroundings temperature differential effects efficiency per process.