Tom Booth

2 hours ago, exchemist said:

I said: "And yes, an engine rejecting less waste heat than the prediction of the Carnot efficiency limit would violate a physical "law" of the universe."

To which you responded: "Where is your experimental proof of this?

That is a stupid response. The Second Law of thermodynamics is - so far as we can tell - a physical law of the universe and the Carnot limit results directly from it. Ergo an engine rejecting less heat that the Carnot limit would violate a law of the universe. It's not a matter of experiment. It's a matter of definition.   

Trouble is, you are not engaged in "scientific enquiry". If only you were. You have an idée fixe, which you have had for a decade now. You spend your time doing pisspot "experiments" in your garage in a hopelessly unscientific way, while determinedly refusing to learn basic science and instead scrabbling around for bizarre and inconsistent justifications for your refusal to accept the Second Law of Thermodynamics.

You are tilting at windmills.

 

It's not a "physical LAW" if a physical experiment demonstrates it can be violated. 1800's style "scientific" [sic] "LAW" [sic] proclamations are no longer considered a form of valid scientific inquiry.

2 hours ago, exchemist said:

Trouble is, you are not engaged in "scientific enquiry".

"You" me (Tom Booth) did not propose an experiment. Swansont proposed an experiment.

I for one would like to hear exactly what he had in mind, but he was shut down.

I suppose next you'll be calling him Sancho Ponza

I guess that's appropriate

Some dragon.

12 hours ago, Ghideon said:

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.

You are able to adopt an idea with a "what if" attitude and think, what would we have to do to see if this is true or not. That's a great quality.

There is nothing special about ice. It's just a handy way to create a temperature differential on the cheap. I've got some in the freezer here in my kitchen so I use it, but pretty obviously I think, anything cold or hot (or both) will do to create a ∆T. You can go above or below ambient (or both).

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

Here's an example of some previous experiments along those lines:

https://www.physicsforums.com/threads/should-ice-take-longer-to-melt-when-used-to-run-a-heat-engine.991714/

There were also some posted in this forum, but that thread was locked:

But if I mention it I'll get banned again I suppose. Speaking of the 2nd law.

________

I've done experiments attempting to measure or determine the "flow" of heat "through" the engine in every way I could think of.

With heat applied, cold applied, ice, propane torch whatever.

One thing I haven't tried is the arangement you suggested. Two engines with the cold sides back to back. Brilliant idea!

The other way around might be interesting too. 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.

12 minutes ago, iNow said:

Hyperbolic much?

You tell me.

He (Swansont) just made the suggestion now, not "14 pages ago", we don't even know the details of his proposal.

Unless you were joking of course.

9 hours ago, Ghideon said:

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:)

Did you read the clip from the video transcript I posted?

I've seen the video and dozens of others just like it.

Feel free to post what you want, you're my hero, but I started this thread on the Stirling Engine Forum in 2010:

 https://stirlingengineforum.com/viewtopic.php?f=1&t=478

The basic stuff the people in here keep trying to educate me on I was studying some time prior to that.

Is there something specifically you want me to get out of that video?

The second law? LOL

Here's another thread on the Physics forum you might find interesting, there was a "Studiot" there at the time trying to have that thread locked down as well.

https://www.physicsforums.com/threads/assumed-violation-of-physics-heat-vs-work.667129/

That was 2013

You should probably be able to find me on half a dozen other similar threads on all kinds of forums debating the 2nd so-called "LAW".

1 hour ago, iNow said:

Yeah, but that was like 14 entire pages ago. Statute of limitations likely applies to evaded counterpoints. 

Evaded by whom. Such experiments I've already uploaded years ago comparing ice melting under running vs. idle engines to see what difference it might make.

But I certainly have no objections to doing more/better experiments along those lines.

Petitioning against scientific inquiry, great platform there. I'm sure you've got everybody's vote!

4 hours ago, swansont said:

So any change in behavior of the engine is a direct result of decreasing the temperature of the cold reservoir.

The ice melted, so obviously heat was flowing to it. What remains is determining if that happened just because of the ambient environment. I suggested an experiment to determine this.

 

What's your suggestion for an experiment. I'm starting to like you better and better Swansont! Great idea! What are the details of your suggestion?

1 hour ago, swansont said:

It’s not an independent variable. Not a state variable that, in principle, can be directly controlled in an experiment.

So?

The ice (or other cold object) i.e. ∆T is an independent variable, the "bounce space" is one of the dependent variables under examination, if only theoretical at this point.

Time for me to take a break from this.

Sorry about any unanswered responses. I will get back to them.

53 minutes ago, swansont said:

I’d say it’s running the wrong tests.

You’re not running the tests that would falsify your conjecture.

My experiments have not been designed to test any speculations on my part. They have been designed to test the Carnot efficiency theorem as, for example, outlined in a previous post.

https://www.scienceforums.net/topic/128644-is-carnot-efficiency-valid/?do=findComment&comment=1228730

8 minutes ago, Ghideon said:

And without ice as a complicating factor? 

 

That would probably be preferable.

But some form of initial cold would be necessary.

There are a variety of ways of accomplishing that. Options have already been discussed.

22 minutes ago, swansont said:

If there’s no heat flow, then the ice shouldn’t melt because of the hot water. Are you willing to make that argument?

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. That is the point of Ghideon's excellent suggestion (or "rhetorical question").

Heat flow via the heat engine to the ice if present could be more easily determined.

Of course 100% elimination of all avenues of heat transfer other than the working fluid inside the engine is probably unrealizable. There must of course be an engine body of some sort which might conduct some small amount of heat etc. But such unwanted transfers could much more easily be reduced to an absolute minimum with the engines sharing the "sink" between themselves, literally between the engines. The heat would then have to be transfered through one engine or the other in order to reach the ice. This eliminated the issue about the potential conductivity of the insulation. There wouldn't:t be any.

I would be willing to say that at a minimum, with the two engine arrangement Ghideon proposed, the ice should melt eventually, but MUCH much much more slowly.

If there is heat transfer, than 2 engines both transferring heat to the ice simultaneously would double the heat input and the ice should melt much more rapidly, relative with some control.

For the ice to NEVER melt would mean there must be some heat transfer in the opposite direction out of the ice rather than into it. I do not rule out that possibility, as, as I've said before, I've seen some evidence that the Stirling engine behaves similarly to a Vuilleumier machine, pulling heat from both the hotter and the less hot ("cold") heat exchangers, (or top and bottom plates).

15 minutes ago, swansont said:

Who said anything about caloric? 

I surmise it to be the basic unconscious assumption behind concepts such as heat "flow", "reservoir", etc. Use of such phraseology conjures up images of a fluid flow.

4 minutes ago, swansont said:

Room for expansion work, whatever you mean by that, is not a variable.

How it that not a variable?

I explained briefly what I mean already, but to elaborate: There is a ceiling and a floor. Obviously if you make something colder and it contracts, lowering the floor, creating more distance between the floor (maximum contraction) and ceiling (maximum expansion) you have provided more room for expansion, which is the actual source of power output (conversion of heat into work).

I could elaborate further if you still don't get it but that might involve posting some video.

21 minutes ago, sethoflagos said:

Yet those best placed to make a fortune if there were any merit to your ideas decided that you were unemployable.

And judging by the way you persistently misrepresent what I and others have actually posted here, perhaps they were having issues with your honesty too.

As far as any potential employment, I have no idea what your talking about.

How do you feel you were misrepresented?

4 minutes ago, joigus said:

Have you read my previous comments? Irreversible work is, to all intents and purposes, indistinguishable from heat in any caloric analyses a couple of seconds after it's been delivered. It's not stored in the form of gravitational potential energy, charge in a capacitor, pressure in a gas, etc. All forms of work that can be 'given back' by the system. It must be included, as @sethoflagos shrewdly pointed out if I understood him correctly, as TdS=T(dS_{irreversible work}+dS_{heat exchange}) to the effects of every conceivable energy balance. If you take Carnot's efficiency formulae --any of them; heat engine, heat pump, refrigerator or José Carreras ("the other one"), irreversible work should be considered as heat, rather than work, as every Carnot recipe only speak of 'work' in the sense of 'reversible work,' not what you bluntly are calling 'work.'

This is, of course, just an educated guess by yours truly, as I've never been brave enough to try to tell anything about an ungodly mess of pumps and fans, and Stirlings, and so on as concerns Carnot's analysis. I wouldn't even know how to begin. Does this go in the denominator? You know...

As you're not distinguishing with any care the difference between irreversible and reversible work, and not taking any calorimetric measures, it's like trying to describe a platypus to a person that's willingly blindfolded and keeps telling you such thing cannot exist.

It all sounds to me like 'sumfin fishy's goin' on, there ain't no platypus."

I'm incapable of following your train of thought. There you are. I hope that clarifies the question as to why I can't clarify the question.

Hmmm...

Work output counts for nothing?

If my Stirling engine drives a generator that lights up a village, powers machinery etc. We should recon that "irreversible" work output as waste heat?

Well that solves the problem I guess. Every work output will resolve back into heat eventually. Lightbulbs, toasters, radiant heaters, cloths dryers, microwave ovens etc. all produce heat. So we can subtract all that from the efficiency. That should balance things out nicely.

3 minutes ago, exchemist said:

Ah, but the trouble is that, in your mounting hysteria, you are not reading what I posted.

All I said was that if an engine were, somehow, to achieve a greater efficiency than the limit predicted by the Carnot formula, then it would break one of the laws of thermodynamics.  That is a true statement that requires no testing, as it is just a matter of applying the 2nd law of thermodynamics to Carnot's cycle, i.e. simply an exercise in theory.      

A theory is just a theory. To establish it as a reality requires testing in reality, not another "exercise in theory".

1 hour ago, joigus said:

It not only "appears to." It does. And Carnot's formula tells you why. So much more so the closest your design is to Carnot's unattainable chimaera.

Heat pump, or refrigerator have different definitions for efficiency, as efficiency is after all, an anthropocentric definition, as shown by the fact that for refrigerators and heat pumps --if I remember correctly--, work, instead of heat source, is what you put in, and thereby appears in the denominator. This, so I understood, was hinted at by Seth in a previous post.

Did you read my later full response?

There is no debate about the increase in efficiency but rather what the actual cause might be.

The cold applied is the primary cause, but I'm suggesting that there might be a secondary cause that explains the increased efficiency without resorting to the heat "flow through to the sink" (or cold reservoir) concept.

The cold might just provide more "bounce space" for expansion work.

I mean, if I might make an appeal to logic, and common sense, if heat is the fuel for a heat engine how does dumping additional "fuel" to a now colder sink improve performance?

In a Stirling or other "pure" heat engine the heat is a consumable; an actual fuel for the engine. One that "disappears" with no residual "waste" product.

On 2/4/2023 at 2:29 PM, swansont said:

On 2/4/2023 at 12:26 PM, Tom Booth said:

It certainly appears that the increased ∆T results in increased efficiency.

That’s the only variable that changed. And work increased from zero to some nonzero value, so there is no arguing about the increase in efficiency

It's not "the only" variable that changed. Room for expansion work has increased also as a result.

It may be that this increased contraction/expansion space accounts for better engine performance (performance of more expansion work) rather than a more rapid or voluminous "flow" of a  magical  caloric/heat to the non-existent  "cold reservoir".

The problem in running tests has been the probable inadequacy of insulation and the insulation acting as a heat conductor rather than an impediment.

That's why I'm rather excited about Ghideons suggestion. It has the potential for virtually, if not entirely eliminating a wild variable.

1 minute ago, studiot said:

 

Quite Frankly, Tom, there are plenty of other members that are more rewarding to talk to than you are so my focus of attention has shifted away from yourself.

That's fine, but this is not the lounge room for idle chatter or endless off topic banter, or a treatise on the Studiot theory of thermodynamics, or the Tom Booth theory for that matter.

As far as I'm concerned the thread can wander where it will, but just please stop whining if I fail to respond to posts irrelevant to the topic I'm interested in focusing on.

21 hours ago, studiot said:

@Tom Booth  you might like to reflect on why neither heat nor work can be considered to be properties.

Relevance?

Is that my "thought for the day" or what's your point exactly?

3 minutes ago, sethoflagos said:

Your not in the kitchen, Tom. The adults won't let you play there any more will they because of what you did.

 

If you do not want to read or respond to posts in an intelligent and constructive way, or make some contribution towards the objectives proposed, why not go waste your time elsewhere and bother someone else with your inanities.

You pretty obviously know absolutely nothing about how a real Stirling engine operates, but if you are going to mislead people I do feel it is within my place here to point out the errors and inaccuracies in your statements as compared with reality.

What you posted about the Stirling engine cycle bears no resemblance to either Robert Stirling's original invention or any subsequent models or modifications.

Compression of the working fluid results in heat not cold. It's elementary thermodynamics.

18 hours ago, studiot said:

 

4) What exactly is expanding and contracting in a single particle ?

Good question. While I agree Kinetic theory provides the best explanation and I generally advocate that, I'm not at all certain of it's absolute accuracy.

For example I picture gas particles under high pressure in an engine cylinder something like marbles packed together in a jar. Can some be actually zipping around at near light speed while others float about aimlessly?

I think "partial pressure" may afford some explanation. Larger air molecules may be packed tightly together while smaller molecules move in between. Maybe possible for a Hot Air engine with mixed gas but what about an engine charged with pure helium and hermetically sealed?

More pressure on a compressed gas and there is phase change to liquid with something like an 800X reduction in volume depending on the gas, the transition is not as sudden as generally supposed perhaps, there is a gradual contraction of the gas.

"4) What exactly is expanding and contracting in a single particle ?"

Perhaps nothing. Presumably there would be no intermolecular forces between particles if there is only one.

19 hours ago, exchemist said:

Thanks. It's very interesting. One can see he was very nearly there. He was on the track of heat being due to motion of the molecules and was becoming sceptical of the idea of caloric being any sort of material fluid. 

Not just "becoming sceptical" he  systematically demolishes the theory:

Quote

 

When a hypothesis no longer suffices to explain phenomena, it should be abandoned.

This is the case with the hypothesis which regards caloric as matter, as a subtile fluid.

The experimental facts tending to destroy this theory are as follows:

 

The list of facts cited by Carnot is too long to reproduce here.

4 hours ago, exchemist said:

Do try to get a grip of your mind. You don't need to actually run a red traffic light to tell whether doing so would break the law. All you need do is read the law.

LOL...

You equate physical LAW with traffic rules and regulations? You really are in sorry shape. In need of a dose of reality, lost in idealizations and abstractions. If the book says, it must be true.

Yes you do need to run the traffic light if someone is alleging it's actually IMPOSSIBLE! if you are going to test the claim. 

On 2/5/2023 at 5:02 AM, studiot said:

 

Yes difficult indeed.

Which is why it is such a shame that you threw your toys out of the pram at a critical moment when I had just posted the diagram showing how Carnot overcame that difficulty.

Again a pity that you did not complete the translation of his works, putting that hugely insightful statement into its proper context.

 

I should point out a typo in the quote from Carnot's unpublished writings: "best" should have been heat:

Quote

But it would be difficult to explain why, in the development of motive power by heat, a cold body is necessary; why, in consuming the heat (not best)of a warm body, motion cannot be produced

Can't say how that cropped in, possibly a. OCR error in whatever online copy I c/p'd. (Some PDF)

As far as your diagrams, I've seen these so-called proofs a thousand times (slight exaggeration, but dozens certainly). As I recently mentioned to Ghideon this thread is not entitled elementary thermodynamics.

You seem to have all your ducks in a row ready to post an entire treatise on the subject from start to finish, that is neither appropriate nor necessary. If you want to play the headmaster of your own thermodynamics course I would suggest you start your own thread on the subject. The focus here is very narrow: Is the so-called Carnot efficiency formula valid or applicable to a Stirling engine, and is it falsifiable: can it be tested experimentally.

If you feel your chart in some way relates to that topic feel free to carry on, if not, carry on anyway if you like, but don't expect a response from me for your off topic derails that threaten to swell to encyclopedic proportions.

Quote

a pity that you did not complete the translation of his works, putting that hugely insightful statement into its proper context.

It's "proper" context is there for all to see. Maybe you could elaborate on whatever it is you might be trying to say there.

How would you interpret Carnot's statement in whatever it is you consider "it's proper context" ?

On 2/5/2023 at 3:22 AM, Ghideon said:

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)

 

Your point?

A clip from the transcript:

Quote

segment:0:14 heat will never be seen to flow spontaneously.

0:17 from a colder object to a hotter object.

Stirling engines are precision engineered machines. Even most of the toys or models. Many people who attempt to build one fail to get it to work, we have them coming into the SR forum all the time asking for help because their engine will not run and they can't figure out why.

There is nothing spontaneous about these machines. Few people even  understand how they are supposed to work. NOBODY really understands fully how they ACTUALLY work I'd venture to guess. They certainly do not work in the way traditionally supposed.

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

On 2/5/2023 at 4:24 AM, sethoflagos said:

TLDR. This stuff is beyond you. Flick the switch on your tin foil hat from transmit to receive. You might learn something.

Sorry for pointing out where you were wrong/ignorant. If you can't take the heat get out of the kitchen as they say.

This thread is about how a Real Stirling engine works and if the dreamt up arbitrary Carnot limit actually applies or not.

Your description of how a Stirling engine operates "opposite" to other heat engines or the Carnot cycle is simply wrong, regardless of what you might have gleaned from Googling up a Wikipedia article that is also wrong.

You might try taking your own advice:

Quote

This stuff is beyond you. Flick the switch on your tin foil hat from transmit to receive. You might learn something.

On 2/5/2023 at 4:25 AM, exchemist said:

And yes, an engine rejecting less waste heat than the prediction of the Carnot efficiency limit would violate a physical "law" of the universe.

Where is your experimental proof of this?

There are at least two interpretations of the Carnot limit, one is basically valid IMO, the other is apparently (based on experimental results and other observations) hogwash.

Which interpretation do you think the little engine might be violating?

1) That at best, discounting friction, inertia etc. Provided 1000 joules of heat the engine can only utilize the 1000 joules SUPPLIED and no more.

Or

2) That at best the engine can utilize 20% or less of the 1000 joules SUPPLIED to it. At best, only 200 joules are available to be converted.

I've seen both interpretations espoused, sometimes in the same article, the writer apparently unaware of the contradiction.

On 2/4/2023 at 2:57 PM, Ghideon said:

On 2/4/2023 at 5:05 AM, 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:

From my general reading on the subject, it is claimed that this Carnot limit applies to ALL heat engines, broadly defined.

My use of the equation seems to be in harmony with how it is generally applied in courses and lectures on the subject, example problems etc.

Here is a typical example chosen at random out of a search result just now.

https://blog.mide.com/thermodynamic-theory-of-the-ideal-stirling-engine

For the authors qualifications, here is his LinkedIn profile page:

https://www.linkedin.com/in/luke-saindon-43971066

Note the following claim:

Quote

To have a Stirling run continuously you need to have a hot section that gets constantly heated by some source, and a cold section that is cooled in some way. Without constantly heating the hot section and cooling the cold section eventually enough heat would be transferred between the two that you would just end up with two warm sections. Once this happens you no longer have this temperature differential between sections, efficiency would drop to 0, and no heat would be transferred through the engine since no temperature differential exists.

 I happen to be doing this exact experiment, testing this claim or assumption. Somehow I cannot equate "cooling the cold section" with my doing the opposite: insulating the cold section with a combination of acrylic, Aerogel and a glass globe. And yet the engine did "run continuously", once it got going.

There is not any misapplication of the Carnot limit on my part. I'm just testing it's general application as given, as others are applying it.

My experiments have consistently produced results contrary to these expectations, (if no [external] cooling is applied to the engine's cold side it should not be able to run).

I'm postulating that in lieu of external cooling, perhaps the engine is effecting internal cooling as a result of expansion work.

This does not seem to be too much of a stretch of the imagination, IMO from general thermodynamic principles. The only real barrier to acceptance of that postulate is the (in my estimation arbitrary) Carnot efficiency limit "Law" or theory or assumption.

Something curious happened during the experiment that seemed rather unusual, I don't know what to attribute it to or what if any significance it might have.

Normally these engines are intended to run on a cup of hot Coffee and are rather difficult to get started and to keep going requiring a relatively high ∆T compared to other Low temperature difference engines.

The most notable feature is  perhaps the loud irregular clatter from the displacer.

This particular model has a magnetic displacer. That is a small magnet attached to the piston lifts the displacer as the piston reaches the down, full compression position.

With expansion the piston pulls away, the magnetic pull on the displacer is broken and the displacer drops down.

This is a very noisy operation as the displacer click up against the top of the chamber then drops back and hits the bottom

There is usually no end to this clatter of the displacer as long as the engine is running, but in the experiment, after the engine was kept running for a very long time on the continuously available steam heat, the engine fell almost completely silent.

All I can imagine is that the engine achieved some homeostasis where the displacer was virtually suspended, caught by the magnet each revolution, before hitting the bottom, then dropped before hitting the top, just oscillating in between.

Covered with insulation I can only guess. Perhaps running for so long the heat softened the plastic so it made much less noise. I can't really be sure without running it that way again without insulation or with a window or scope inside.

It's probably insignificant, but I'm curious to find out what was actually going on for the engine to run so smooth and silently when normally it is so annoyingly loud. 

Another thing that struck me as unusual was that while trying to fix the insulation my finger inadvertantly got caught by the flywheel and it actually hurt a little and the engine did not stop.

These engines usually stop at the touch of a feather. It seemed to have more torque than when running under normal circumstances without insulation.

This has been a consistent observation. These engines run with either more speed or more torque or both and also run longer (if the heat source is finite, like a cup of hot water) when the cold side is insulated. 

By "these engines" I mean LTD Stirling engines generally, not just the magnetic type.

31 minutes ago, swansont said:

There is no cut between you putting the first engine on the boiling water and starting it up. The cut is before that. You take the engine off, show the water, and put it back on. So it’s cooling off for about 10 seconds, but has no problem starting up after. 

Your video documents things that are irrelevant and fails to document things that are. You’re not showing the engines under the same conditions and not explaining these details until someone calls you out on the inconsistencies in your narrative.

Valid criticisms to some extent as it was a completely unplanned raw video taken in my kitchen when I happened to have some time.

I recorded what I thought relevant at the time. If I recorded everything the video would have been 3 hours long.

Ten seconds is no time to cool down after sitting over steam for ten minutes.

Another problem was the flywheel on the #2 engine was buried in the insulation which I made as thick as possible. I had tried trimming it away with an exacto knife, but had not done a very good job, so there was some drag on the flywheel of the second engine from the flywheel contacting the insulation. I kept trying to push the insulation down out of the way but it kept puffing back up.

If you watch more of the video it can be seen clearly that at one point the engine wouldn't run, then it almost stops and I push the insulation down and it picks up speed and keeps running.

I think it's pretty clear the problem was the insulation causing drag on the flywheel.

After that first video, the next day I cut away the insulation a little more and with a slightly better set up, made a second video but only posted it too the Stirling engine forum because of the issues with posting video here.

In the second run I was able to work out some of the problems like steam getting through and under the blanket and inside the glass globe as well as the insulation rubbing. And some better temperature readings in preparation for using the probes, which I have yet to do.

Just now, swansont said:

 

I’m not talking about the first engine. That’s not the one that repeatedly stops, that you claimed didn’t stop.

”There’s no obvious cut as you transition from one system to the other. It looks like it’s all one take.” is clearly not talking about the lead-in to the first engine.

The only reason for having the first engine in the video at all was so people could see the type of engine that is under the insulation. So I didn't bother recording the start up for the first engine which is largely irrelevant IMO, but the first engine went through several false starts as well. That is very typical for this type of engine.

I just got the first engine going off camera and then restarted the film when I had it warmed up and ready to run.

8 minutes ago, swansont said:

That’s interesting, because the heater is clearly on and there are bubbles, as if it’s just about to boil, just as it was when you stopped the uninsulated engine and removed it and showed the water. The first engine started right up. 

There’s no obvious cut as you transition from one system to the other. It looks like it’s all one take.

 

 

If you watch carefully there is a beep and jump in the video of sorts  between the time  water is poured into the steamer and when it boils. That actually took a few minutes for the water to get up to a simmer.

The first engine had all that time to warm up and was ready to run when I restarted the camera.

1 hour ago, swansont said:

You ask in the OP why it doesn’t stop, but it clearly stops! You don’t comment on this at all. 

My phone has a limited recording capacity, so I had paused the video several times.

With the first engine without insulation the engine sat on the steamer until the water got up to boil so the engine was already well pre-heated over the simmering water for some time. I paused the camera during the warmup period.

The second engine with the Aerogel blanket insulation had a cold start. It is quite typical of Stirling engines to take some time to reach operating temperature and have a few false starts if not yet warm enough.

------------

The reason Stirling engines in general typically need a few pushes to get going is that they have some characteristics of a "Maxwell's demon" and it usually takes some time for the hot and cold working fluids to become segregated.

How this takes place is that during compression the working fluid is displaced to the hot side of the chamber. Then with expansion the working fluid is displaced over to the cold side.

I'm sure you are aware that when a gas is compressed it heats up, expanded it cools down. So while turning the engine over by hand, at one part of the cycle, the gas is compressed and moved to the hot side, then for the other half of the cycle the gas is expanded and moved to the cold side, back and forth., back and forth rapidly until a temperature differential is well established and the engine can run freely.

Of course this segregation or heat pump activity is maintained once the engine is running well.

On 2/4/2023 at 2:29 PM, swansont said:

Who said heat is not passing through to the ice? Certainly not me.

It has been the observed outcome of my several experiments.

Heat applied to the engine on the hot side does not appear in a measurable form in the quantities suggested by the Carnot efficiency formula at the presumed "sink" (cold side).

So, this has lead me to ask the question: if heat is not passing through to the ice, what could be the reason?

My measuring instruments don't seem to be broken.

So is the Carnot efficiency equation really valid?

The first response I inevitably get is that I'm a crank or whatever, but hay, I've recorded it all on video. There is nothing preventing anyone from doing these simple, inexpensive experiments.

I've had engines running on the flame from a propane torch on the hot side with hardly any change whatsoever at the "sink".

If the heat isn't passing through, this leads me to doubt the Carnot efficiency equation, or the interpretation that states such a large percentage of the supplied heat in actual Joules absolutely MUST be "rejected" to the "cold reservoir".

So, can this be tested? Maybe there is some basis for concluding that the equation does not actually apply to Stirling hot air engines.

I mean Carnot et al were talking mainly about steam engines.

In a steam engine some water is brought to a boil in an enclosed vessel where it builds up pressure.

A small amount of steam, under high pressure is admitted to the cylinder with the piston at or near TDC through a valve which is then quickly shut.

The pressurized steam is then allowed to expand performing work pushing the cylinder. The steam is then allowed out to a condenser.

Well, we have the latent heat of evaporation stored up in the steam at boil, then released as heat of condensation.

It is natural and actually accurate to conclude that the steam has in some way "transported" heat from the boiler to the condenser, because it has.

A Stirling Hot Air engine however does not involve any such phase change. There is only the expansion and contraction of a gas.

Should we expect that the same amount of heat be "transported" in a hot air engine as in a steam engine?