Isolated cold hole

[matt brown]

bump

[Fool]

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Removing work increases efficiency. Removing "waste heat" reduces efficiency.

Why you favor the latter is a bit of a mystery.

As a scientist, I'm taught to avoid favoritism. I favor neither of that false dichotomy. One of theses days you may just learn why heat rejection, (not a waste), is necessary for an engine to have greater than zero efficiency. Without rejecting heat your engine will have zero work output. This is evident in all the LTD Stirling experiments you have demonstrated, and why I harp on measuring the work output. Not because it will prove Tom or Carnot wrong, neither will happen, but to prove what I suspect, near zero work developed. Near zero heat out means, near zero heat in, and near zero work produced. Heat applied, is not the same as Qh heat absorbed, (You erroneously assume that.).

You still, after 20 years, do not understand simple F=Ma, and W=F∆x=P∆V. Or for an impulse: Work equals the integral of dP•dV. And how they relate to PV=nRT and how that correlates to reality in the engines we work with. You've even been given the slightly more complicated formula for real gasses, yet you completely fail to mention that. You also seem to want to apply the molecular attraction formulas to gas equations, when they clearly apply to liquid and solids or during the transition to liquid. You don't yet understand where and why they have negligible effect, as in our work here on LTD Stirling Engines.

Wow! Look how much I must type, just to show how one single erroneous statement of Tommy's, misleadingly casts an erroneous assumption on my thoughts, as if he knows jack about what I prefer. How would Tommy know what I'm thinking? He wouldn't. ('What I prefer!') What a crackup! Get a life. Grow up. Learn some real science. Stay far away from me.

Hint: What is real science called? Science.
What is, non-real science, an attempt at real science, or pseudoscience, called? Quackery. Those other terms are contradictions. There is no such thing as fake knowledge. It's either knowledge or lies. Memorizing a lie is not learning. Building on memorized lies is not learning.

You either know what I'm thinking, or you are lying about what I'm thinking. The only way you could know what I'm thinking is, if you were me. Guessing is lying.

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[Fool]

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Repulsive molecular forces are limited to overlapping electron clouds, apparently.

I think overlapping electron clouds only happens to solids and liquids. Gasses bounce off the electron clouds, no overlapping. But I don't know how close the molecules get. You are bringing your and my lack of quantum theory, into a discussion of the macroscopic theories of thermo and fluid dynamics. The scientific lecture, presented through YouTube, on that subject should have explained why quantum mechanical effects were negligible for higher level modeling. I guess you didn't get that point from it. It was the main point he was extending. Cheer up, lots of students fail to consider a professors main points, and consistently do poorly on an exam. Those students typically waste their study time on irrelevant side points, like quantum mechanics, in a fluid dynamics class. I've seen it happen, and helps those as peers, fellow students. Study what isn't negligible.

The main point here is that repulsive forces are responsible for bounce. They add nothing to the kinetic energy of the molecule. The attractive forces don't add or subtract anything from the kinetic energy of the gas molecules either. Once a gas, both can be ignored, until the kinetic energy slows enough to be close to the boiling temperature and density. Then size also matters. Phase transition and below.

You keep bringing phase change points into a discussion of engines that operate nowhere near phase changes. Yes for steam power, no for Stirlings. No for gas molecules far away from each other, or even bouncing off from each other. The kinetic theory applies to gasses, not to liquefaction temperatures and densities.

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[Fool]

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Instead of removing "heat" it is better to remove "work".

All Matt was saying was that you can't "remove work".

When a gas expands it does work, work out.

When a gas is compressed it has work done to it, work in.

No other points are possible. Total work out of the gas will be work out minus work in, for a complete cycle. That is from the gasses viewpoint.

Tom, I can tell, from your descriptions here, that all your experiments with gasses and engines have been in an Earth surface atmospheric pressure. You are observing a mixture of inside gas behavior with outside gas behavior. It apparently is confusing you.

I suggest you try some gas and engine experiments inside a vacuum chamber. They are relatively cheap, or can be built from common items, like a pressure cooker and thick, glass, acrylic, or polycarbonate plate and cheap Harbor Freight hand pump vacuum brake bleeder. Understanding what science means by 'gasses always push', 'gasses and hydraulics never suck', will become apparent only after doing some vacuum chamber testing.

https://www.amazon.com/dp/B095YGCQFT/re ... p13NParams

That is only an example. Not necessarily the best deal on vacuum equipment. $150...

Take an all glass syringe, push it in completely. Plug the hole. Put it in the vacuum chamber. How much does it expand? All the way? Less?

Suck up some water. Point it up. Push it all the way in, ejecting all air an water. Leave water in just the tip. Eject all air, no bubbles. Plug the tip. Put it in the chamber to see how much it expands. All the way? Less? Try it with hotter water and syringe.

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[Fool]

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The displacer barely lifts away from the hot plate leaving a relatively huge cold space above the displacer, probably 20 times more cold air volume at minimum than the maximum hot air space volume.

So what you are saying is that very little heat gets into a LTD engine.

No, not at all.

The surface area for heat exchange is about equal top and bottom. The aluminium bottom is at least 2000 times more thermally conductive than the acrylic+aerogel top.

Obviously, given that the engine is running heat is entering at least at the metal/air interface. The air inside the engine is itself a very poor heat conductor so the air molecules not needing to conduct heat but only transmit pressure helps explain why any Stirling engine using air as a working fluid could ever run at all.

All that dead air space above the displacer is mostly just additional insulation that cannot transfer any heat, but CAN transfer PRESSURE.

The heat transfer is likely very localized at the aluminium/air interface - surface area so very little movement of the displacer is necessary to run the engine no-load.

Under load, a higher lift on the displacer could force additional air into direct contact with the hot metal plate but heat transfer to the piston would be non-existent, only indirect pressure would influence the piston.

The displacer barely lifts off the hot plate, Allowing a very small volume of gas to contact it. Even if it does a full temperature swing, most of that will be from the regenerator, not actual heat input. It then drops back down pushing the gas back through the regenerator. It converts that tiny input of heat to enough expansion to run a very tiny engine, but no work output. It then can only have left, a very tiny amount of heat to reject to the cold plate. This is true, even if it is 80% of the tiny amount of heat it brought in just to run the tiny engine.

How do you expect to measure such a tiny temperature rise? How is your insulation going to block such a tiny amount of heat flow?

Again, your experiment is interesting but hardly thermodynamically significant.

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[Tom Booth]

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The displacer barely lifts away from the hot plate leaving a relatively huge cold space above the displacer, probably 20 times more cold air volume at minimum than the maximum hot air space volume.

So what you are saying is that very little heat gets into a LTD engine.

No, not at all.

The surface area for heat exchange is about equal top and bottom. The aluminium bottom is at least 2000 times more thermally conductive than the acrylic+aerogel top.

Obviously, given that the engine is running heat is entering at least at the metal/air interface. The air inside the engine is itself a very poor heat conductor so the air molecules not needing to conduct heat but only transmit pressure helps explain why any Stirling engine using air as a working fluid could ever run at all.

All that dead air space above the displacer is mostly just additional insulation that cannot transfer any heat, but CAN transfer PRESSURE.

The heat transfer is likely very localized at the aluminium/air interface - surface area so very little movement of the displacer is necessary to run the engine no-load.

Under load, a higher lift on the displacer could force additional air into direct contact with the hot metal plate but heat transfer to the piston would be non-existent, only indirect pressure would influence the piston.

The displacer barely lifts off the hot plate, Allowing a very small volume of gas to contact it. Even if it does a full temperature swing, most of that will be from the regenerator, not actual heat input. It then drops back down pushing the gas back through the regenerator. It converts that tiny input of heat to enough expansion to run a very tiny engine, but no work output. It then can only have left, a very tiny amount of heat to reject to the cold plate. This is true, even if it is 80% of the tiny amount of heat it brought in just to run the tiny engine.

How do you expect to measure such a tiny temperature rise? How is your insulation going to block such a tiny amount of heat flow?

Again, your experiment is interesting but hardly thermodynamically significant.

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When you have some experiments of your own to show, your opinions might be worth some consideration.

[Fool]

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Really? You think I went through college without doing any experiments? I assure you I did. And was around others doing and commenting on them. You have plenty of gall to think you've done things that no one else has. Please quit being so ignorant.

Please understand that I can in fact put a scientific test/experiment together in a properly equipped lab and document the process properly. You haven't.

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[Tom Booth]

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Really? You think I went through college without doing any experiments? I assure you I did. And was around others doing and commenting on them. You have plenty of gall to think you've done things that no one else has. Please quit being so ignorant.

Please understand that I can in fact put a scientific test/experiment together in a properly equipped lab and document the process properly. You haven't.

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Prove it liar.

[Fool]

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I have. You don't understand. You don't even try.

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[Tom Booth]

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I have. You don't understand. You don't even try.

I can in fact put a scientific test/experiment together in a properly equipped lab and document the process properly.

I said prove it.

Do any experiment, video record it and post the results.

I don't think you can tie your own shoelace.

[VincentG]

My larger epoxy chamber engine is nearly complete, so I will be able to perform experiments on heat consumption in a large, insulated box with a known heat source while measuring air temperature increase over time.

My thoughts at this time are that the box will increase in temperature equally with and without work. From everything I can gather, I believe that heat itself is not consumed, but instead temperature is consumed.

That is to say, a 100 joule heat source driving an engine will go on to heat the box just as if the engine were not running, only faster, as the engine will be working as heat pump.

A harder test would be to show that the same 100 joule heat source would heat the box an equal amount with no engine at all, only much faster.

[Tom Booth]

My larger epoxy chamber engine is nearly complete, so I will be able to perform experiments on heat consumption in a large, insulated box with a known heat source while measuring air temperature increase over time.

My thoughts at this time are that the box will increase in temperature equally with and without work. From everything I can gather, I believe that heat itself is not consumed, but instead temperature is consumed.

That is to say, a 100 joule heat source driving an engine will go on to heat the box just as if the engine were not running, only faster, as the engine will be working as heat pump.

A harder test would be to show that the same 100 joule heat source would heat the box an equal amount with no engine at all, only much faster.

Naturally, if nothing ever leaves the box. The"work" will convert back into heat, air friction or whatever.

Could your engine run a generator?

Have the generator running outside the box or at least powering a heat source outside the box. An incondecent heat lamp, some nichrome wire or whatever.

If you get just as much heat inside the box as with no "work" output, then where is the heat outside the box coming from?

You will have "overunity".

[VincentG]

Yes it will run a generator. It will have adjustable displacement from 40cc to 200cc for the power piston and for now a 150cc displacer chamber.

If you get just as much heat inside the box as with no "work" output, then where is the heat outside the box coming from?

You will have "overunity".

Once the temperature is equalized in the box, it will be a far lower temperature than the original Thigh. In order to return to the original Thigh at the same quantity, work would need to be put back into the system. So I don’t agree that it is overunity.

The work is coming from the fluid like flow of energy that is caused by the temperature gradient, and not specifically the overall quantity of heat energy.

[Tom Booth]

Yes it will run a generator. It will have adjustable displacement from 40cc to 200cc for the power piston and for now a 150cc displacer chamber.

If you get just as much heat inside the box as with no "work" output, then where is the heat outside the box coming from?

You will have "overunity".

Once the temperature is equalized in the box, it will be a far lower temperature than the original Thigh. In order to return to the original Thigh at the same quantity, work would need to be put back into the system. So I don’t agree that it is overunity.

The work is coming from the fluid like flow of energy that is caused by the temperature gradient, and not specifically the overall quantity of heat energy.

I think I see what you mean.

Taking the fluid analogy, (if it is just an analogy)

If you had two columns of water joined at the base by a valve, one full, the other empty. Open the valve and the volume would equalize. Not all the fluid is going to transfer. It will be divided 1/2 and 1/2.

You still have say 1 gallon that ends up divided as 1/2 gallon + 1/2 gallon.

The total "joules" is the same but the "temperature" is lower by 1/2.

Still, if you calculate the joules going in to heat the box with the engine not powering an external generator outside the box and get a 20° temperature rise inside the box.

Then run the experiment again with the heat engine running a generator that powers a heater outside the box and get the same 20° temperature rise inside the box while also generating additional heat outside the box, then you would have a "spontaneous" generation of heat from nothing.

Or, how would you explain that?

Anyway, if you can do such an experiment, it should be interesting.

[Fool]

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I have. You don't understand. You don't even try.

I can in fact put a scientific test/experiment together in a properly equipped lab and document the process properly.

I said prove it.

Do any experiment, video record it and post the results.

I don't think you can tie your own shoelace.

I would be happy to do so and get right on it, as soon as I'm provided a properly equipped laboratory and a salary so I can waste time redoing Tom's botched temperature anomaly demonstrations. Anyone, or organization like a University, want to offer such?

Tom's fluid analogy gives some interesting side thoughts. What if the tubes were different diameters? Starting with one gallon going into a much smaller tube would only allow, say 1/4 gallon to flow into the other section. They'd still end up at the same height, but higher than the equal sizes.

Similar to a very large and massive hot plate flowing into a tiny cold plate. They'd still end up the same temperature, but higher than for the equal sizes.

Or the other way around. One gallon almost all flowing into a pancake shaped tank.

Or heat flowing into a running, no load, heat engine, ejecting all the heat, Carnot and friction, into the atmosphere and the atmosphere staying the same temperature. Now we are asking how much? What percentages? Work for heat conversation?

Good testing with your new heat box, Vincent.

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