Ghideon

49 minutes ago, Tom Booth said:

With an arrogant attitude, presuming we already know everything there is to know about the universe, there would never be any further progress in human understanding.

That's why I keep my mind open to new ideas* and use heuristics to navigate around old failed stuff. I know for instance that a Perpetuum Mobile of Villard de Honnecourt does not work; it does not matter if it is painted in a new color. 

Regarding the idea in the opening post; do we neglect the mass of some of the moving components? 

*) In my profession new ideas emerge almost daily. Not new physics but new ideas that really challenges what is established.

26 minutes ago, Tom Booth said:

Such a process does not require any overthrow of any well established and experimentally verified "Laws of Physics" that I'm aware of.

Bold by me. Awareness about the limits of physics may save time; focusing efforts on what is possible and rejecting the impossible ideas early.

33 minutes ago, Tom Booth said:

What about it?

Are we discussing what is possible according to established laws of physics or new/modified laws of physics?

1 hour ago, Tom Booth said:

Nothing related to the function of the Maxwell's Demon itself. But if a temperature difference can be maintained, that would be something that could be done with the ∆T. Run a thermal differential engine or two, or three, or four or eight or whatever.

Ok. How about conservation of energy? 

There seems to be four stirling engines in the first picture, what are those for?

34 minutes ago, Tom Booth said:

This is your round-robin. You tell me the details of your proposed setup. Is your heat source finite, like a hot piece of metal or infinite like an electric heating element?

It's just a quick idea based on what you posted earlier, nothing worth exploring further if there is no interest.

20 minutes ago, Tom Booth said:

What would be the heat source?

What you proposed:

On 2/7/2023 at 6:25 AM, Tom Booth said:

Sandwich the heat source between two engines

But you have not given any details as far as I can see.

Side note while I wait answers to some previous questions:

On 2/7/2023 at 6:25 AM, Tom Booth said:

The other way around might be interesting too. Sandwich the heat source between two engines.

Have you thought of combining the two types of arrangements? It is probably too mechanically complicated to be useful or realisable but may trigger further ideas: Arrange an even number of Stirling engines in a "Stirling Ring"; hot against hot and cold against cold in a circle. In this thought experiment, what could be the result when applying your ideas?

1 hour ago, Tom Booth said:

Sure Looks like a temperature gradient to me.

You seem to cherry pick the first picture? What about the picture that show the experiment at a later state? 

24 minutes ago, studiot said:

The term for this is cable powered router.

Good idea. PoE (Power over Ethernet) may also be applicable; one PoE & LAN signal repeater somewhere between house and caravan

30 minutes ago, studiot said:

Can you put plugs on the cable ends yourself or get someone to do this ?

Personally I prefer a wall jack and a patch cable between wall & equipment.

10 hours ago, Tom Booth said:

I think the rate at which ice melts also makes a good gauge or measure for comparison testing.

I disagree, there are too many unknown variables.

10 hours ago, Tom Booth said:

Sandwich the heat source between two engines. Makes measurement so much easier. The heat cannot dissipate to the surrounding ambient without going through one or the other of the engines. Very clean data should be obtainable.

 I don't see how that experiment helps you debunk established theories.

28 minutes ago, Tom Booth said:

how it is to be interpreted as an upper ceiling (or whatever name anyone might want to call it) on efficiency for any given situation?

I'll take a look at this later!

3 minutes ago, Tom Booth said:

If the ice could be completely isolated from the surrounding ambient heat so that any heat reaching the ice MUST pass through the engines working fluid That would certainly simplify measurements.

And without ice as a complicating factor? 

One reason for me to ask questions and try to get into the details about your hypotheses and your possible explanations is to find possible improvements in the experiments. For instance if ice was crucial to the experiment I would suggest various ways to get repetitive results from that. If low temperature is the thing that actually is required I intuitively try to simplify how to cool the things instead of how to manage the ice. And maybe if the problem is to get the engines staring when cold side is at ambient temperature that can be managed as well.

It all serves to remove variable things that others could have problems to repeat or that may be tricky to reproduce in your setup. None of these requires an explanation of the result before running the experiment but it helps to create a setup that have fewer sources of errors while at the same time does not introduce bias regarding the hypothesis. 

7 hours ago, Tom Booth said:

Your point?

Why do you have to ask; isn't it obvious since you know thermodynamics?

(And I will not try to explain; you asked me not to:)

7 hours ago, Tom Booth said:

BTW, I appreciate the concern, but generally speaking people can stop trying to teach me about fundamental thermodynamics.

11 hours ago, studiot said:

I'm having a little trouble sorting the sheep from the goats in this paper.

Thanks for your reply. My intention was to support your comment by adding a scientific example where Carnot terminology was used in what I believed was at the edge of its applicability. Sorry if I misinterpreted and added confusion. I have not (yet) possess the knowledge to comment on the results or methods in the paper.

35 minutes ago, exchemist said:

Yes, the opening paragraph makes clear they only claim to beat the Carnot limit in a small  number of non-equilibrium cases. The Carnot cycle, like just about all of classical physics and chemistry, is concerned with equilibrium thermodynamics, i.e. regimes in which concepts such as temperature have a meaning.  

Thanks; that seems to be the point I tried to make by providing the example. 

2 hours ago, Tom Booth said:

Or that "rejects" just 79% of the heat supplied REALLY overturning some physical "LAW" of the universe ?

Based on personal experience from my garage; the second law of thermodynamics can be compared to the contents of a spilled assortment box. The contents of the box tend to end up in a disorganized mess. The probability of the contents of the box becoming sorted is low.

(Side note: Here is a video describing the statistical aspect of thermodynamics; the description does not rely upon archaic steam engines:  https://www.khanacademy.org/test-prep/mcat/chemical-processes/thermodynamics-mcat/v/second-law-of-thermodynamics)

9 hours ago, studiot said:

the Carnot formula is not hogwash if used for the purpose for which it was intended.

@Tom Booth here is an example where the scientists probe at the limits of applicability:

Quote

The Carnot cycle imposes a fundamental upper limit to the efficiency of a macroscopic motor operating between two thermal baths. However, this bound needs to be reinterpreted at microscopic scales.

...

Quote

an experimental realization of a Carnot engine with a single optically trapped Brownian particle as the working substance

Source: https://www.nature.com/articles/nphys3518.pdf

(I do not wish to take the discussion off topic, we discuss the case of Carnot limit for macroscopic engines. Just wanted to share in case there is any interest in papers discussing limits of applicability in the context of Studiots comment.)

5 hours ago, Tom Booth said:

What words or phrases, sentences or paragraphs exactly can't you follow? Of which post?

What is hard to understand or complicated about putting some cold object between two engines?

I''m thinking as an experimenter. When ice is added, for instance under insulation between two engines, I find it complicated to see when all the ice actually melts; I may disturb the experiment. Instead I prefer to use only a thermometer. 

Thinking again, this is a good idea:

7 hours ago, Tom Booth said:

Let's say we dip a coin of known heat capacity into liquid nitrogen and put the coin in a circle cut out of a silicone mat the same thicknes as the coin.

What if you instead of ice have a thermometer probe pre-cooled and inserted at the cold side? Then you can see the temperature all the time and the pre-cooled probe takes the role of the ice? If something more massive than the probe is required you can attach the probe to some object of suitable size and shape (The probe may heat too quick when moved from freezer to engine setup). Maybe a thin sheet of metal? 

3 minutes ago, Tom Booth said:

What would be the outcome in order of melting (or running) time?

According to established science or your ideas?

The ice just complicates the scenario; would it be possible to discuss an ice-less scenario? I can't follow your descriptions, sorry.

Can we agree that you expect a cooling effect on the cold side? I mean, if ice does melt slow in your experiment then, according to your description, the running engine is keeping the temperature lower that ambient at the cold side? 

On 2/1/2023 at 12:10 AM, Tom Booth said:

colder than ambient temperature reached by the working fluid

If so we can discuss the consequences and a simplified experiment without the errors and failures that the ice will cause.

@Tom Booth did  you see my post regarding an addition to the experiment? https://www.scienceforums.net/topic/128644-is-carnot-efficiency-valid/?do=findComment&comment=1228275

(May have been overlooked since there were some x-posting and editing)

3 hours ago, Tom Booth said:

Great, and I'm more than happy to prove my hypothesis wrong. So IMO it's a fantastic suggestion for an actual experiment.

Let's outline the logical next step by using one addition. Assume the setup works; We have the Stirling engine running and cold plate insulated with an adjacent Stirling engine or good enough insulation. Place the running engine(s) in a well-insulated box. 

All the work performed by the engine(s) will be friction loss in the engine or movement of air inside the box. These losses will heat the air inside the insulated box. Conservation of energy means no energy enters or exits the box and no energy is permanently lost in the box, just changing between heat and mechanical work. The running engine(s) keep the cold side cool, and the losses are heating the air. In principle the box is a sealed system, and the engine will never stop since a permanent difference in temperature is established. This goes against my understaning of physics, but it seems to follow logically from your ideas and your conclusion of experiments?

3 hours ago, Tom Booth said:

There is though, I believe, at least one very real example of a "self-running" cooler/heat engine utilizing evaporative cooling.

Can you provide a reference? It could add value to the discussion.

(As far as I know it is ok per forum rules to link to further reading)

1 minute ago, Tom Booth said:

Well OK. Rhetorical.

So you thought I would say "Oh no, that can't work!!!" or some such response?

Hey, my theory is perfectly falsifiable by your method. I'm very grateful for the suggestion. If there is a way to DISPROVE it, conclusively, then I can put all this behind me and get on with the rest of my life.

I have no desire to continue wasting time and money on nonsense.

 

The logical consequence of your idea seems to be that you are just one simple component short of creating a major breakthrouh in physics. But I do not believe in such machinery therefore my question was rethorical. But I would be happy to be proven wrong. 

12 hours ago, Tom Booth said:

Hope you have no objections,

Sharing is ok with me but note that my question was a rethorical. Elaborating may take the thread off topic but I’ll clarify if you wish. 

13 hours ago, sethoflagos said:

An ice block fresh out of the freezer should be oto -18 ^oC (0 ^oF) throughout. Even it has been left a while, the surface may well be at freezing point, but the bulk of the inside may be considerably colder. 

When it is placed under the cold plate of a Stirling engine, it is effectively insulated from ambient air while it continues to lose heat to the inside of the block.

It is entirely consistent for the engine to appear to run well, rejecting a certain amount of heat to the ice interface, while that interface freezes and cools further due to a greater heat loss to the core.

The cold reservoir is in this case the core of the ice block and the distribution of its temperature is unknown

Thanks for your comments! I guess proportions are also a concern; a really large piece of ice on a low power engine allows for other factors to have significant impact? Also freezers are maybe not built to precision, hysteresis may allow for the ice to have different temperatures. A few degrees may make a difference when a small engine melts the ice.

15 minutes ago, Tom Booth said:

There are a lot of additional Ifs to consider. If the engine timing is adjusted properly, if there is proper load balancing (not a lot of excess heat) If the engine is performing sufficient work output, off the top of my head.

That seems reasonable. But under the insulation the temperature will be rather stable once the Stirling engine has run for a while? Temperature will likely vary depending on the load and added heat (and more) but if the effect you propose is there the temperature should read below ambient if the insulation is good enough. Initially it is good enough tho show experimentally, beyond doubt and in a repeatable fashion, that effect you predict exits; exact numbers can be found in later experiments?