Modified "Hot" Beta engine

Discussion on Stirling or "hot air" engines (all types)
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Tom Booth
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Re: Modified "Hot" Beta engine

Post by Tom Booth »

Hey! I think this guy stole my idea for that piston with the long straight connecting rod going through the other piston. I wonder what kind of hot air engine he's making?


https://youtu.be/Sc9Znjepcp4?si=ZXWdL56DSkhT7li4


Sorry stephenz, I mean YOUR idea.

Looks like he's building an Alpha with 180° offset too.
Fool
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Re: Modified "Hot" Beta engine

Post by Fool »

stephenz,

Thank you for the posts. Iterative computations are awesome. A bit above many of those reading these posts, but who needs them? Right? Good work and thanks for the tips.

I suspect that an Alpha has several configurations and parameters that can be tweaked to provide a great variety of compression ratios. Cherry picking one type really is self defeating. Perhaps they will learn. Still several posters here, I can tell, are with you. I like to see us concentrating on those areas you pointed out. Displacer volume to working volume. Regenerator volume to effectiveness. Alpha timing. Piston crank offset. Lost motion links. Pressurized verses thinner walls. Double action and balance of moving masses. And some of it is discussed.
VincentG
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Re: Modified "Hot" Beta engine

Post by VincentG »

If one is to compare different configurations and their compression ratios, it must be looked at that with some comparable metrics with all pistons/displacers have the same swept volume. And if you do that, Alpha's win in the common usable range.
I have to push back here again, as there really are no comparable metrics. If we were to level the playing field, a parallel cylinder Alpha would have to be considered like the Rider engine. Otherwise, the cylinder angle of the 90-degree Alpha alters the phase angle of the 90-degree crank.

In any event I think we can all agree that if the goal is to reach usable power density levels, there are likely many avenues available, so pick yours(this is not directed at anyone specifically) and try and make some progress. Otherwise, developmental engineering is probably not the right field(or hobby lol) to be in, where progress is stifled by dogma and in some cases, rational thinking.
Tom Booth
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Re: Modified "Hot" Beta engine

Post by Tom Booth »

The title of this thread is "Modified "Hot" Beta engine" for a reason.

As explained in the opening post: (edited for length and relevance)
OK, so here is what I'm thinking.

My reasoning and experiments over the years has led me to believe, right or wrong, that heat engines don't require cooling. At this point I no longer feel that this is just theorizing, I think I've demonstrated experimentally that it is at least possible, and in my estimation, a Stirling type heat engine often runs better without any kind of cooling jacket or sink.

Logically, to my mind anyway, a heat engine runs on heat so why should it ever be intentionally cooled?

(...)

Anyway, conjecture aside, I've been pondering what sort of design could be used to eliminate the cold side, ( ...) nix the cooling and instead retain the heat for power output as much as possible.
As an Alpha operates on an older (200 year old) theory of how heat engines are supposed to operate and having a dedicated COLD cylinder an Alpha configuration is, I think, pretty much completely ruled out for the purposes of this discussion, which is to develop an engine design that completely eliminates the cold side or cold cylinder.

As far as I'm concerned, the whole Carnot limit / second law debate ended with this experiment:


https://youtu.be/LG09AXAjpio?si=osARxXYY0BIsmiza


Even in this high temperature engine, the engine continues to run with no aluminum cold sink in the middle and no cooling of the power piston, and no cold end or heat gradient in the "stack" So I'm moving on from theory to design.

I've posted a mountain of clear empirical/experimental evidence, text references and theoretical models over the past decade that IMO adequately explain the experimental results, as well as numerous other observations, such as the ROCKNTV1 account of his engine running much better with boiling hot water instead of cold water in the "cooling" jacket.

This and any many other observations simply do not fit in with and cannot efficiency "LAW" and cannot be explained by the old theories of Carnot, Kelvin and Clausius.
Tom Booth
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Re: Modified "Hot" Beta engine

Post by Tom Booth »

A bit rushed in my last post and missed several typos. If not clear the last paragraph should read:

This and many (not "any") other observations simply do not fit in with the Carnot (not "and cannot") efficiency "LAW" and cannot be explained by the old theories of Carnot, Kelvin and Clausius.
Tom Booth
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Re: Modified "Hot" Beta engine

Post by Tom Booth »

Fool wrote: Sat Dec 30, 2023 10:07 am
Tom Booth wrote:The "first law" thermal efficiency equation is:

Qh=Ql+W

Which I don't have a problem with. It does not imply that work can exceed the heat input, but neither does it suggest that the work output in Joules cannot match the heat input in Joules.

The first law does not forbid the existence of an engine more efficient than the Carnot limit, not at all.
Qh = Qc + W

Or rearranged:

W = Qh - Qc

Second Law:

Efficiency ratio:

n = W/Qh

Or combining first and second

n = (Qh-Qc)/Qh = 1- Qc/Qh

Qh and Qc have a linear relationship to Temperature. Meaning add 100 Joules get 100 K temperature increase. Add 200 Joules get 200 degrees increase.

So they are of the following form:

Qh = Th x Cv + K
Qc = Tc x Cv + K

Y intercept, constant: K = zero because, at absolute zero Kelvin, there will be no heat. Qh and Qc will be zero at zero Kelvin Temperature.

So those two simplify to:

Qh= CvTh
Qc=CvTc

Putting those into the previous equation for n, efficiency:

n = 1 - Qc/Qh

Or

n = 1 - (CvTc)/(CvTh)

The Cv's cancel, becoming one, which leaves:

n = 1- Tc/Th

That is Carnot's Theorem derived from the first and second laws. The first law, conservation of energy, manifests itself into a great many following areas. Maximum efficiency is just one of those.

Here is a more rigorous proof:

Relationship to ideal gas law:

https://en.m.wikipedia.org/wiki/Thermod ... emperature

Scroll down to the appropriate section. It uses a slightly higher level of mathematics.

There are other more complicated proofs should you care for them. It has been proven many different ways.

The Carnot Theorem is just for thermodynamic efficiency. Kinematic efficiency reduces the efficiency even further. And not following the ideal engine cycles, also reduces the efficiency.

Efficiency is a valent goal to pursue, but mostly a waste of effort for a starting concern. Power to weight ratio is a much better pursuit. Think American Drag Racer. 1/4 mile per 12 gallons. 48 gpm. Excellent.
Thanks, but I've been through all these "proofs" and equations a hundred times already.

The way it looks to me is you start with the first law.

Then you have this completely arbitrary "Carnot" (more like Clausius) "limit" adopted as a premise, and like trying to fit a square peg in a round hole just insert an "=" sign between the two. Out pops "entropy" and all kinds of other nonsense.

It's like you adopt a premise that all men are 7 feet tall, then use that for all your calculations.

It might seem to work most of the time on the basketball court, but it's a false premise with limited application and fundamentally simply not true at all outside of some very limited circumstances.

As they say, even a stopped clock is right twice a day. You just need a very limited field of vision and ignore all the anomalies.
Fool
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Re: Modified "Hot" Beta engine

Post by Fool »

Wow! Thanks for the compliment. I guess from your response that everything mathematical is correct in my supplied proof. Good. Great.

I'm sorry you were unable to follow it. Your erroneous comments on it is telling. I would be happy to explain further if you ask specific questions as to where you begin to disagree. If no questions, I'll assume you are uninterested in the truth.
stephenz

Re: Modified "Hot" Beta engine

Post by stephenz »

@ Tom, since you asked. This was the message I was referring to.

Anyway it's pretty much off topic, and since the only for you to be convinced is going to do the Maths which you (probably?) won't do, there is no point talking about it anymore.
Tom Booth wrote: Thu Dec 28, 2023 1:54 pm Anyway, a Beta type Stirling, which seems to have been Robert Stirling's original patent design, looks like a way to achieve a much higher compression ratio than other types of "Stirling" engines.
Tom Booth
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Re: Modified "Hot" Beta engine

Post by Tom Booth »

Fool wrote: Sat Dec 30, 2023 10:57 pm Wow! Thanks for the compliment. I guess from your response that everything mathematical is correct in my supplied proof. Good. Great.

I'm sorry you were unable to follow it. Your erroneous comments on it is telling. I would be happy to explain further if you ask specific questions as to where you begin to disagree. If no questions, I'll assume you are uninterested in the truth.
The problem is not so much with mathematics. Math is math, it can't really be "wrong" it's the underlying assumptions and how the math is interpreted that I have issue with.

Like the height of a human male assumption already given as an illustration.

If you assume "men" are 7 foot tall then the combined height of two men is 14 feet.

Nothing wrong with the mathematics.

But if you hire five "men" to pick apples from an orchard without a ladder and they can't get the job done you might be scratching your head wondering why.

Anyway, as a conversation could drag on and on as it usually does, I'd prefer it not be on this thread please, but if you really want to get into it, I started another thread for that here:

viewtopic.php?f=1&t=5601

First question is already posted awaiting your response.

You can fire your apple pickers for being "lazy" and one false assumptions leads to another.

Eventually you end up with some basketball players picking apples and your happy, but never question the underlying assumption.
Tom Booth
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Re: Modified "Hot" Beta engine

Post by Tom Booth »

stephenz wrote: Sun Dec 31, 2023 12:05 am @ Tom, since you asked. This was the message I was referring to.

Anyway it's pretty much off topic, and since the only for you to be convinced is going to do the Maths which you (probably?) won't do, there is no point talking about it anymore.
Tom Booth wrote: Thu Dec 28, 2023 1:54 pm Anyway, a Beta type Stirling, which seems to have been Robert Stirling's original patent design, looks like a way to achieve a much higher compression ratio than other types of "Stirling" engines.
Your. Assumptions are incorrect.

First of all, that passage is in no way a "claim". That is a mischaracterization. Saying that something "seems" or "looks like" is not a "claim"

Further, I've been looking at and doing the math backwards and forwards repeatedly for the past decade. The math is logically flawed, as is being examined now on another thread, though "fool" seems to have carried out another hit and run and flown the coop which seems to be his usual practice here when he comes trolling. Or perhaps he's just enjoying the New Year, as I should be doing.

BTW, Happy New Year everyone!

You are welcome to stand in for him if you would like, or simply add your own two cents, or more studied insights and "proofs" if you like, on that thread:

viewtopic.php?f=1&t=5601
stephenz

Re: Modified "Hot" Beta engine

Post by stephenz »

OK great, it wasn't a claim. That statement sounded like one. Sorry English isn't my native language. That statement is still wrong. Cool. Good talk.


You need to need to stop expecting people to do stuff for you, no one here owes you anything. I've been patient enough to tell you where to start if you want to verify why Alpha's have been compression ratios than other configurations (everything else being equal). I said it was high school level, and after checking it's actual middle school level, at least where I come from it's the case.

If you aren't trolling can you post your "backwards and forwards" Math efforts? How hard have you tried really? Couple of Sine, Cosine and Pythagoras' theorem. Or are you gonna question that theorem too? After all a theorem is just a statement.

And no, I will not venture into trying to explain thermodynamics/thermal engineering to you as you are not willing to set aside everything you think you know in order to keep an open mind. It would be a waste of time. In fact I am wasting my time right now.
Tom Booth
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Re: Modified "Hot" Beta engine

Post by Tom Booth »

stephenz wrote: Mon Jan 01, 2024 12:43 pm ...

You need to need to stop expecting people to do stuff for you, no one here owes you anything. I've been patient enough to tell you where to start ...

If you aren't trolling can you post your "backwards and forwards" Math efforts? ...

And no, I will not venture into trying to explain thermodynamics/thermal engineering to you as you are not willing to set aside everything you think you know in order to keep an open mind. It would be a waste of time. In fact I am wasting my time right now.
OK, you had previously said that you had some equations or math or proof or something, than you just said over on my other thread:


"I'm happy to try to explain things again in one of your threads."


viewtopic.php?f=1&t=5537&p=21079#p21081

So, I was offering. I just didn't want you to feel left out or excluded.

I'm certainly not in need "stuff explained" to me. I mind my own business mostly. You and others apparently cannot restrain yourselves from jumping in on your own accord to "educate" me, throw insults and start up a debate, as you did just recently here with the words:
I am only responding here because frankly I am sick and tired of reading non-sense which can't be answered to...
viewtopic.php?f=1&t=5598&p=21033#p21024

Nobody came knocking on your door asking for your help, but your welcome to participate in the debate if you so choose.
stephenz

Re: Modified "Hot" Beta engine

Post by stephenz »

Tom Booth wrote: Mon Jan 01, 2024 2:40 pm "I'm happy to try to explain things again in one of your threads."
I was referring to the simple geometric math proving how Alpha's will always inherently larger compression ratio than Beta's and Gamma's (assuming all phase angle/piston/displacer/stroke dimensions being equal). I offered to help with that, cause I thought it's something you might be able to accept getting corrected on - since it's so basic, teenage math. At this point, I think I was mistaken. As for the thermodynamics part, it's not that I don't have Foul's patience to try to lay things out for you, it's just that I think your mental agenda will reject whatever we throw at you, and as such is a wasted effort.

But yeah, maybe you are right: ignoring you completely. Among many others I have tried to point out mistakes or provide you with some more realistic explanations to your "numerous" experiments that seemed to contradict science but somehow those explanations are never good enough to you. There is nothing in it for me here, I'm merely trying to contribute to this community. I just wish this forum wouldn't have the tendency for posts to derail into pseudoscience, perpetual bs, etc. so often. That part is ridiculous. If that's your jam, I'm sure you can find some facebook group or something where you'll find people that think alike.

The Stirling cycle is an amazing thermodynamic cycle that is well understood and described by hard Sciences, that's a fact. Whether or not you understand (or not) how they fundamentally work does not change that fact. And you not being able to find a random internet person to explain this to you, also does not change that fact either. Thermodynamics is not easy, 15-20 years ago, 2-3 years thermodynamics were mandatory for the mechanical/thermal engineering programs, they were hard courses, lots of people had a hard time to follow, it's not very intuitive, not very concrete. 15-20 years later, in a different country, I frequently hire new thermal/mechanical engineers - and I always ask a few basic thermodynamics questions during interviews, mostly for fun/curiosity, and people have a hard time with it.

My point is: you disagree with Carnot (or whatever that it is that you are currently "challenging"), guess what: that's fine. But don't expect to be taken seriously if your explanations are bleeding statements proving your lack of understanding of the physics or even fail to provide equations proving you theories. The burden of proving your theories is on you, not on anybody else.

On this note, good luck to you.
Tom Booth
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Re: Modified "Hot" Beta engine

Post by Tom Booth »

stephenz wrote: Tue Jan 02, 2024 12:06 am
Tom Booth wrote: Mon Jan 01, 2024 2:40 pm "I'm happy to try to explain things again in one of your threads."
I was referring to the simple geometric math proving how Alpha's will always inherently larger compression ratio than Beta's and Gamma's (assuming all phase angle/piston/displacer/stroke dimensions being equal). I offered to help with that, cause I thought it's something you might be able to accept getting corrected on - since it's so basic, teenage math. At this point, I think I was mistaken. ...
Mistaken about what?

Your insurance that Alphas inherently have higher compression or mistaken about my willingness to be "corrected"?

I made a passing statement. Your getting all up in arms about nothing. I happen to have a different opinion about the compression ratio of an Alpha. As far as I'm concerned it's of absolutely no consequence.

If you think it's that important, go right ahead, now I'm curious. What could be so critically important about the compression ratio of an Alpha for someone to raise such a fuss about it?

Please, I'm all ears. You have the platform.

Let's have a look at this math: "simple geometric math proving how Alpha's will always inherently larger compression ratio than Beta's and Gamma's (assuming all phase angle/piston/displacer/stroke dimensions being equal)."
VincentG
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Re: Modified "Hot" Beta engine

Post by VincentG »

I'd like to see the math. Not sure how an Alpha can compete volume ratio wise. Even if the cylinders are assymetric to change the compression ratio, the ratio of hot space to cold space is changed equally. Betas and Gammas just don't have this particular limitation.

Every design evolution I've seen for an Alpha eventually starts to look and function more like a Gamma.
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