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OT from The "Ice Bomb" thermal engine


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Posted (edited)

My reason for appearing here, was, a little over a week ago, I had posted a question on the Stirling Engine Forum I frequent:

Quote

W = Qh - Qc

How does that thermodynamic equation work out for the "ice bomb"?

There was no response. So I thought perhaps the knowledgeable folks on this or another Science forum might have some input.

I don't think I've received an unequivocal answer. Perhaps the equation can't be used because this engine doesn't behave in the expected way, and something about steam tables and not having a glacier or something along those lines.

Would anyone else like to offer an opinion?

Maybe just an ordinary heat engine? So treat it as such?

T hot = ambient T cold = freezer so W should work out to be?

Plug in some realistic numbers I guess.

Say ambient 70°F and freezer, I guess we could make 20°F

Sound reasonable?

What's W? Work is it, right?

Convert the numbers to the Kelvin scale.

Am I even using the right formula for efficiency?

266.483 ice box

294.261 ambient

Efficiency = 1-Tc/Th is it?

1 - 0.9056008101651

Is 0.0943991898349

So, the decimal moves 2 places and that gives roughly 9.4% efficiency

That's absolute maximum of course right?

Would that be the whole ice engine setup?

If say 200 or whatever Joules of heat are taken in from ambient heat per hour then 18.8, with loses, say 10 joules of work could be extracted?

Well, with friction, mechanical loses etc. 5?

Converts to 3 or four foot pounds of torque I guess? (Or so an online converter spits out).

Anyway, trying to be conservative, it looks like there is at least some potential for power output.

Now, does that include the entire apparatus freezer and all, or does the power to run the freezer have to be deducted?

I'm guessing the answer will be that the power to run the freezer has to be deducted, so there is really no point and it's all a hopeless waste of time. Right?

Or is it like someone said and the whole thing is not amenable to conventional mathematical analysis?

I don't know really. I'm sure I've got the math all backwards even if it were applicable.

My main question was T hot is usually equated with heat input.

But in the freezer, power is produced by taking heat away.

So, no matter, just flip it around?

I'm really not intentionally trying to make anything difficult or confusing.

To be honest, the whole efficiency formula seems simplistic and meaningless.

It's just the temperature difference.

Literally, just the temperature difference.

294.261 - 266.483 = 27.778

27.778K is exactly 9.43991898349% greater than 266.483 on the Kelvin scale

So "efficiency" it's just another way of writing the temperature difference.

How does that make sense?

Anyway, why should empirical evidence, or actual experiments be taboo on a science forum?

Actual video and measurements, temperature readings, things of that nature.

I'm much more comfortable with something I can actually run and take measurements on, but whenever I do that, the posts are sent to trash or the tread is locked.

Does Science not do actual experiments anymore?

 

Edited by Tom Booth
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1 hour ago, Tom Booth said:

It's just the temperature difference.

Literally, just the temperature difference.

294.261 - 266.483 = 27.778

27.778K is exactly 9.43991898349% greater than 266.483 on the Kelvin scale

So "efficiency" it's just another way of writing the temperature difference.

How does that make sense?

Sorry, I stated that the wrong way around, but maybe someone gets what I mean.

If 70°F is taken to be "all the heat"

20°F is the sink.

In kelvin that's a 27.778 difference.

So if we divide all the heat by 100 so that 294.261K = all the heat that's 2.94261

So taking the difference and divide by 2.94261 we get the same exact value as the "efficiency" to like the tenth+ decimal place.

So called maximum heat engine "efficiency" is just the temperature difference on the Kelvin scale written as a percentage?

 

4 minutes ago, iNow said:

130 posts in 4 days. He’s “not getting it” on purpose, folks. 

From my pov, it seems like nobody else is "getting it".

I understand the consensus, (mostly) pov. I just can't say that it actually makes sense to me.

Especially like, when I test something to try and find out which pov is correct and witness the results myself and I'm told my results are simply "impossible" so, nobody knows what but I did SOMETHING wrong.

It's like I get off an airplane in a country where people still believe flight in a plane is impossible, and nobody will believe I just got off a plane.

I can show you my plane, it's just behind those trees, we can take it for a ride, see for yourself.

I have pictures, see.

The pictures are torn up. Nobody will look.

I've been on at least three science forums now where I was told my VIDEO shows a "perpetual motion machine" and the thread is locked because it's against forum rules or something.

Seriously? It's just a heat engine folks. A TOY model engine at that.

I'll send everybody one for free, do the experiment yourself.

Thread locked.

Wow.

 

 

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35 minutes ago, Tom Booth said:

I understand the consensus, (mostly) pov. I just can't say that it actually makes sense to me.

It’s amazing how well you can contradict yourself even within a single sentence. That’s quite a talent.

I believe you’re being intentionally obtuse, willfully ignorant, and not discussing the topic in good faith. 

37 minutes ago, Tom Booth said:

Thread locked.

Wow.

The thread obviously isn’t (yet) locked given that I’ve just replied. See last point above about failure to engage the discussion with intellectual honesty and good faith. 

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Posted (edited)
2 hours ago, iNow said:

It’s amazing how well you can contradict yourself even within a single sentence. That’s quite a talent.

I believe you’re being intentionally obtuse, willfully ignorant, and not discussing the topic in good faith. 

The thread obviously isn’t (yet) locked given that I’ve just replied. See last point above about failure to engage the discussion with intellectual honesty and good faith. 

I think I can legitimately state with absolute honesty that About 10 or 12 years ago I 100% accepted that a heat engine operated by shunting heat from the hot side of the engine to the cold side. It made perfect sense to me.

I was on the Stirling engine forums asking questions, reading, and just wanted to know how they worked so maybe I could build one to run off my wood stove.

I studied, read, watched hundreds of videos and had no reason to doubt the accepted, consensus wisdom on the forums.

If you heat up air it expands and pushes the piston. If you then cool down the same air it contract and the piston can be pushed back by the momentum stored in the flywheel.

Nobody at that time had ever imagined that a heat engine could run without a flywheel.

But in time I saw things about heat engines that made no sense to me. That made me scratch my head trying to figure out how that could be possible.

One guy accidently discover his engine could run without a flywheel.

Some engines just seemed to run too fast. It took like five minutes to get the engine hot enough to run, and it would run five more after the heat was removed, but ran at 3000 rpm or something. Heat just doesn't conduct through a steal plate that fast could it?

Well, so I started reading up on thermodynamics, but had to settle for whatever old textbooks I could find on the subject in libraries or online and such, so, maybe some stuff was obsolete.

What struck me was when I read about how heat can be converted into work in a heat engine, and that as a result the heat actually "disappears". It's no longer inside the engine but went out as "work" so in actuality, did not need to be removed.

How amazing is that?

Well that really explained a lot of my observations that were puzzling me.

Heat when converted to work "disappears" instantaneously. Or some old texts related.

So THAT'S why some engines can run so fast.

So THAT'S why the flywheel isn't needed to push the piston back down the cylinder.

In some engines, though, the piston returned with more force than what the heat added could force it out.

In other words, it seemed that air was expanding so far, then coming back on it's own with so much force it crashed into the HOT end  on its own. That looked impossible.

So in trying to figure out that one I thought well, maybe so much heat is being removed as "work" that the air in the engine is getting colder than it normally would.

Let's see. Heat pushes the piston out as far as it will go, as far as the gas will expand, but the piston is heavy and has momentum, so the momentum carries the piston further. But the air has already expanded as much as it wants, so now the piston's momentum is stretching, or pulling, "expanding" the air more.

There are a lot of cooling processes going on simultaneously. Heat converted to work, mechanical expansion, there is an air passage the air passes through, an orifice. Joule Thompson throttling.

Why not anyway? Heat drives the piston out to the full extent possible. Energy is stored as momentum. The stored energy then does more work. Then as the air cools and comes back, the piston, (that engine had magnet attached to the piston) passes the coil generating electricity, which is more work being done as the air is already contracting, and, well, the engine is moving so fast, no time for heat to conduct out through the sink, so with all that cooling maybe the sink is not needed.

Maybe the air in the engine is actually getting COLDER than the sink!

Well with that inspiration, I returned to the Stirling engine forum, and basically they all just laughed and tried to explain how a Stirling engine works, and NO absolutely not, putting insulation on the cold side of the engine won't help it to run better.

The heat has to go out to the sink to cool the air (inside the engine). Otherwise the engine won't run. A Stirling engine can't run at all with the heat sink insulated in some attempt to keep the atmospheric ambient heat outside from going backwards into the engine.

But... But...

I was pretty sure I was right. If the sink were insulated so heat couldn't enter from the sink/ambient/cold side then it might be able to refrigerate itself more and run better, gradually getting colder and colder, instead of the heat building up like water behind a dam, it would be converted into heat more efficiently.

Well, I didn't have an engine to carry out my experiment. But I prodded the model Stirling engine builders who HAD engines to try it on to try it.

None ever did. Not worth bothering, we all know it can't work ha ha.

Well, I put the idea on the shelf for another ten years, until an Uncle died and left me some money, so I could just go out and purchase a half dozen engines to experiment with.

Finally I did my experiment, after wondering about it all those years.

I thoroughly Insulated the sink side or the engine so no heat could pass through, set it on a hot cup of water and gave it a whirl, expecting everybody was right and it would just come to a stop because the heat had nowhere to go. No way for the engine to cool back down.

But it ran. And it kept running.

I timed how fast and how long. I ran "controls" with identical engines.

The insulated engines ran longer at higher RPM and ran more vigorously, like it was on high octane gas or something.

I'm not being deceitful or trying to pull anyone's leg. I video recorded the experiments.

Then there were more and more experiments with strange unexpected results. I tried running an engine backwards on ice, and while the engine was laboring hard, because the piston I made was too tight, well the ice that had started to melt re-froze while the engine was running, and the engine got frozen on the cup of ice and I had a hard time getting it loose. When I broke it loose and got it running again, it got frozen, or refrozen.

A few oddball results by one person don't prove anything, but there is a pattern. It appears that heat in these engines is not flowing through to the sink as everybody has assumed that it must for the past 100 years.

I never heard of Tesla at the begining of all this but at some point I came across his article in Century magazine 1900, where he explained the results I was seeing in his refutation of Carnot I guess you could call it.

But I had come to my own conclusions before I came across what seemed like confirmation from a well know person of science.

Anyway, if nobody here is interested, no choice really but for me to move on I suppose and quit wasting time.

That's what my girlfriend keeps telling me. "Why do you bother? Why waste your time?"

I feel I'm trying to just selflessly share some hard won knowledge and information. Not charging anybody anything, all on my own money and my own time.

OK so a few times I tried starting some crowdfunding to raise money so I could do experiments and build engines, but no luck there either.

Seems like this "2nd Law" has everybody completely brainwashed, so they can't even look at what's right there in front of them.

Won't dare look at all. Won't even think about it.

Quote

I believe you’re being intentionally obtuse, willfully ignorant, and not discussing the topic in good faith. 

Believe what you want. Nothing new.  As someone pointed out, I've been at this for years. I just think it's my duty of sorts to put it out there and share with whomever might listen, or whomever might come along in the future.

My latest project is a computer controlled engine to try out some things that aren't possible when the displacer is attached to a crankshaft. 

This is just my first attempt at programing the Arduino to work a servo to control the displacer motion.

 

 

Edited by Tom Booth
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I don't see what is so contradictory about saying I understand a point of view, I just don't completely share that point of view. Given my way of looking at things and my experiences in life, I see things differently. I'm willing to discuss it, and I will try very hard to understand why someone else thinks the way they do, or sees things differently, and I'm more than willing to be convinced, if the argument or explanation they present makes sense.

But when people just take on an air of authority and expect me to accept whatever they say without question, I'm not impressed.

For example, the only logical solution I have been able to come up with for the formula for the Carnot efficiency of a heat engine, why it calculates nothing but the temperature difference is that it is a holdover from Carnot's own theory of heat. It's the maximum "height of the fall" that the "caloric" can travel, from the hot reservoir to the cold reservoir.

It is known that the entire premise on which this mathematical formula is based is completely erroneous and not representative of reality, yet it is still taught and used and spoken of as if it is absolute, unshakable, unquestionable physical law.

Yet, when I examine it closely, it makes no sense whatsoever. It doesn't even add up. At this point in time it embodies two incompatible completely irreconcilable pictures of reality.

If my heat engine is 500 degrees on one side and 250 degrees on the other than the "caloric" can only fall 250 degrees from 500 down to 250 which is 50% of the "fall" on the way down to absolute zero. (Arbitrary numbers on the Kelvin scale but it works out the same way on any other) That makes my engine 50% efficient, at best, because that is as far as the "caloric" can possibly fall.

It is a hard limit for the same reason that sea level is a hard limit. The liquid can't flow any lower than the lower reservoir.

If we know heat is not a fluid, but energy that can be converted, then why continue to use a formula derived from a misconception about the very nature of heat.

So I'm told that the original theory was wrong and nobody believes it anymore, but "somehow Carnot managed to get the math right", though he had no concept of absolute zero at the time.

The whole thing is a hodge lodge of irreconcilable theories munged together by a completely simplistic formula that takes into consideration nothing whatsoever that has any actual influence or bearing on any engine efficiency.

I understand how it works, or is supposed to work, I think. But I can't for the life of me understand how people can actually believe it.

It has no foundation or basis whatsoever in reality. It's nonsense.

Why should anyone give it a second thought?

It doesn't even work out in practice in a way that makes any sense, because if an engine actually IS 100% efficient, "carnot efficiency" might be 15% or 20%

If my heat engine utilizes ALL the heat fed into it, and converts every bit of it into useful work so no heat whatsoever "flows out" into the sink, carnot efficiency might be calculated at almost any arbitrary number represented by the temperature difference.

How efficient the engine actually is doesn't enter into the calculation at all. It's complete hogwash.

 

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You're confusing Carnot efficiency, 1 - TC/TH

... with thermal efficiency, 1 - QC/QH

It is entirely consistent with both classical thermodynamic theory, and centuries of detailed empirical observation by the most gifted of experimentalists, for a machine to have a low Carnot efficiency (the fraction of energy in an input stream that is available for conversion to work) and a high thermal efficiency (the fraction of that available work you manage to convert to actual work)

The following demonstrates most clearly that you are totally unaware of this distinction:

1 hour ago, Tom Booth said:

If my heat engine is 500 degrees on one side and 250 degrees on the other than the "caloric" can only fall 250 degrees from 500 down to 250 which is 50% of the "fall" on the way down to absolute zero. (Arbitrary numbers on the Kelvin scale but it works out the same way on any other) That makes my engine 50% efficient, at best, because that is as far as the "caloric" can possibly fall.

With an inescapable effect on the authority of your output:

1 hour ago, Tom Booth said:

It's complete hogwash.

 

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Posted (edited)
5 hours ago, sethoflagos said:

You're confusing Carnot efficiency, 1 - TC/TH

... with thermal efficiency, 1 - QC/QH

Yes, I thought so, as I mentioned, something didn't look right. The result of a hasty cut n paste on the Stirling engine forum, which I then repeated here.

Quote

It is entirely consistent with both classical thermodynamic theory,

Which "It". Sorry, I copied the wrong equation to start with. The Carnot efficiency is what I meant to address.

At any rate, that a theory is more or less consistent with itself is no empirical validation.

Quote

...consistent with both classical thermodynamic theory, and centuries of detailed empirical observation by the most gifted of experimentalists,

Please site an example.

I've heart this affirmation repeated over and over and over, but that seems to be all it is. I've scoured through the available literature for ten years and find no accounts whatsoever of any detailed experiment demonstrating, for example, the actual heat flow in and out of a Stirling engine, running a Stirling heat engine on ice, insulating the sink, nothing whatsoever that would either add weight to or call into question Carnot's conclusions.

What I have found is that in Carnot's own journals, not published until many years after his death, he expressed grave doubt about his own theorem. Stating: to paraphrase, as I don't have it in front of me: If heat is Kinetic energy, it is difficult to understand why a cold sink should be necessary.

Of course, it can be assumed there have been limitless experiments over a centuries time, but infact, Carnot himself conducted none, as far as I'm aware. In his book he confessed he did not have access to so much as a Steam engine, as they had not yet been introduced in France.

His thoughts were just that. Mostly philosophical, not empirical.

From then on the "observation" has been almost 100% exclusively: hundreds have made the attempt to construct a "self acting engine" but none have succeeded, it can be concluded therefore that it is impossible.

End of story.

Please give me one example of "detailed empirical observation" by ANYONE, gifted or not, specific to this order of Stirling type heat engine, or any other for that matter of the "external combustion" class.

Hardly anyone in history ever really fully comprehended how these engines worked, no less built any for experimental analysis.

They were superceded by the internal combustion engine and electric motors and forgotten for the most part for 100 years, until recently.

I'd LOVE to have the opportunity to read such a detailed empirical, experimental analysis.

Finding NON WHATSOEVER myself, after a long and diligent search, I concluded I was obliged to fork out the cash to buy half a dozen such engines and/or build and/or modify my own, and run some tests.

As far as I was able to find, nobody ever really bothered, everybody just assumed that others already have.

Please, please, please fill me in, so I can be saved the expense and effort involved in reinventing the wheel, or going over old ground already covered.

One example of anyone ever insulating the sink for example to measure how cold it might get if thermally isolated from the outside environment.

Nobody ever tried it because it seems completely ludicrous and goes completely against accepted ideas about how these engines operate.

It is just assumed that some 75 to 80% or more of the heat in a heat engine running at 20-25% Carnot efficiency is being dumped into the sink, and the engine couldn't run otherwise.

Apparently that's a complete fallacy.

Edited by Tom Booth
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58 minutes ago, Tom Booth said:

Yes, I thought so, as I mentioned, something didn't look right. The result of a hasty cut n paste on the Stirling engine forum, which I then repeated here.

Sorry, but I don't buy this explanation. 

Take this example from a previous post:

7 hours ago, Tom Booth said:

If my heat engine utilizes ALL the heat fed into it, and converts every bit of it into useful work so no heat whatsoever "flows out" into the sink, carnot efficiency might be calculated at almost any arbitrary number represented by the temperature difference.

 If there was "no heat whatsoever" flowing into your cold sink, that would imply that the thermal efficiency of your machine was 100% (it can't be, but we'll let that pass for now). In other words, you were extracting every last milliJoule of work allowed by the 2nd Law of Thermodynamics.

However, if your heat engine did indeed "utilize ALL the heat fed into it" from say 1 kg of hot cocoa, then you would not only have your 100% thermal efficiency, but you would also have attained 100% Carnot efficiency

Congratulations!

Now explain to me what you did with that 1 kg lump of cocoa at absolute zero. 

Because that is what "ALL the heat" means.

If on the other hand, you actually ended up with luke warm cocoa, the Carnot efficiency simply tells you what percentage of "ALL the heat" was actually available to you. It says nothing whatsoever about the virtues or quirks of your machine - it is an absolute limit for any machine that was fueled by 1 kg of hot cocoa and exhausted 1 kg of luke warm cocoa. And it's a simple function of those two temperatures.

Please pause and reread the last few paragraphs. You've wasted a fair chunk of the last few years through not understanding the difference between the highlighted terms. How much more time can you afford to waste?

1 hour ago, Tom Booth said:

Please site an example.

I've heart this affirmation repeated over and over and over, but that seems to be all it is. I've scoured through the available literature for ten years and find no accounts whatsoever of any detailed experiment demonstrating, for example, the actual heat flow in and out of a Stirling engine, running a Stirling heat engine on ice, insulating the sink, nothing whatsoever that would either add weight to or call into question Carnot's conclusions.

Carnot's equation is a simple algebraic manipulation of the 2nd Law limit - delta S = 0

Experimental verification of the 2nd Law automatically verifies the Carnot limit.

The first item to pop up on Google was: 

"Experiment to verify the second law of thermodynamics using a thermoelectric device", Gupta, V. K.; Shanker, Gauri; Saraf, B.; Sharma, N. K.  American Journal of Physics, Volume 52, Issue 7, pp. 625-628 (1984).

I've not read it, but I'm sure it's fine, and typical of many thousands of similar published papers. It's actually based on a Seeback-effect heat engine, but the underlying principles are just the same.

If you want to see more, just Google "experimental verification of 2nd law of thermodynamics" as I did. There's over 6 million results for you to sift through.

Good hunting.

 

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17 hours ago, Tom Booth said:

I understand the consensus, (mostly) pov. I just can't say that it actually makes sense to me.

!

Moderator Note

And we went through this before. It ended up with the thread being closed, and you were told not to open up a new thread on it.

Doing an end-run by bringing it up in a thread on another topic isn’t allowed.

 
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