Carnot reveal for Tom

[Tom Booth]

On the other hand, aside from the above, if "all" the heat added in the start of one cycle is exhausted during the power stroke and the piston continues on further due to momentum, then the piston is mechanically expanding the working fluid near the end of the power stroke, but the piston is still not doing "work" on the gas to expand it exactly. The piston is still doing work against atmospheric pressure which allows the gas to continue to expand, the pressure falling below ambient. At that point the expansion of the gas IS the result of work done by the piston if that is what you mean.

[VincentG]

I think there's a few things to consider..

In scenario 1, lets assume an in cylinder TDC condition of 20psi at an ambient 70 degrees F(just to use round numbers) driving the piston towards BDC. Is the gas itself imparting molecular energy to drive to piston, or is the gas pushing outwardly between the cylinder and piston? The former implies that the mass volume of the gas is pushing against the piston, similar to a rocket. I don't know enough to discount this, but I find it unlikely. In any event, the expansion of the piston towards BDC has caused the gas temperature to drop below ambient.

In scenario 2, lets assume an in cylinder condition of 20psi at 250 degrees F. Given the same expansion ratio, the final temperature should be higher that scenario 1. Conventional thinking says that the piston is still being driven by 5psi over atm, so where is the extra heat energy going? Is the impact of the gas on the piston now playing a role in power production? If so, how can we quantify this separately from a pressure reading?

[Tom Booth]

There is an interesting experiment on this thread demonstrating a thermoacoustic Stirling with no physical piston, just an "air piston".

The gas appears to behave like a pulse jet engine. Not sure if that addresses your question but your mention of "like a rocket" brought that experiment to mind.

viewtopic.php?f=1&t=5310&p=16434#p16434

[Tom Booth]

...

Tom,
The atmospheric pressure will help push a piston back in during compression, however it opposes it during expansion. The two are equal and opposite, hence can be ignored. They add to zero net work. True of buffer pressure too.

The crossover effect does reduce the need for mv, flywheel, piston mass, to carry the engine through compression and expansion. I.e., allows smaller masses. Provides acceleration in both directions. But it doesn't add any net energy production out of the engine.

I would not say exactly that atmospheric pressure "adds" energy, but as you say here: "atmospheric pressure will help push a piston back in during compression, however it opposes it during expansion. The two are equal and opposite"

Pretty much like in lifting a weight "potential energy" is "stored" which can be returned or utilized when the weight is lowered, I don't think I ever suggested anything beyond that.

Can it be IGNORED? Or should it be? I don't think so. It has been ignored I think for the past 200 years resulting in the false belief, up until fairly recently, that it would be impossible for the piston to return, or for a hot air engine to run at all without energy stored in a flywheel.

Also your statement "The crossover effect does reduce the need for mv, flywheel, piston mass, to carry the engine through compression and expansion. I.e., allows smaller masses. Provides acceleration in both directions" suggests that some solid mass is required other than the gas itself, a piston, flywheel or at least a revolving crankshaft or something.

I think the experiments by tibsim of engines behaving similar to a pulse jet when the piston is removed or absent proves that it is the gas itself expanding and contracting, not the weight or stored momentum in the piston, so atmospheric pressure is not just "helping".

The working fluid is expanding and contracting against the "air spring" of atmospheric pressure. The piston, apparently, is mostly just going along for the ride. At least that's how it looks to me, taking into consideration the balance of all the evidence.

Anyway, you are mistaken if you think I'm trying to "prove" so-called overunity or perpetual motion or Tesla over Carnot or whatever.

In trying to simply figure out how a Stirling engine works, so I could build one to run off my wood stove I ran into these various opposing or conflicting viewpoints and have been attempting to objectively carry out experiments to see which view, or views actually hold water.

Tesla suggested:

let us reflect a moment. Heat, though following certain general laws of mechanics, like a fluid, is not such; it is energy which may be converted into other forms of energy as it passes from a high to a low level. ...

.... If the process of heat transformation were absolutely perfect, no heat at all would arrive at the low level, since all of it would be converted into other forms of energy. ...

Yes he was saying that Carnot and Kelvin and the 2nd law of thermodynamics are wrong, or that there is a loophole, and yes he was suggesting a "self acting engine" or kind of perpetual motion machine.

I personally have no stake in the debate, or difference in opinion and never did. I just wanted a working engine I could use at my off-grid camp. I was never educated in thermodynamics or the 2nd law. I knew nothing about Carnot or Tesla or their difference in scientific view or opinion. I still could really care less who was right, but my experiments so far, in trying to find out one way or the other seem to me to be coming down rather solidly on Tesla's side of the fence.

Heat is a form of energy that can be converted into other forms of energy, not a permanent substance or fluid.

By experiment and actual measurement it appears that indeed: ".. If the process of heat transformation were absolutely perfect, no heat at all would arrive at the low level, since all of it would be converted into other forms of energy". Apparently at least some Stirling engines meet this criteria of "perfection" because surprisingly, I often can detect no heat at all arriving at the "lower level" or cold side of a Stirling engine.

You have, in the past, called me a "pseudoscientist". I can only say you are entitled to your opinions, and I will simply carry on with my research, wherever it leads.

[Nobody]

Tom,
I would never use that label. I despise that word. It's not as bad as "fake news" but very close. It is an oxymoron. Like saying something is a true-falsehood. I did a search on it. It has been in five posts here. All yours, where you accuse others of using it.

I did a search on that term with the ending -science. It comes up seven times. All, but one, are by yours, accusing others of the term. We have a very civil group here. There is no need to point fingers at anyone especially since there will be four pointing back at you or me.

I have tried different tactics here, not all perfectly civil, but found the civil ones work best. I went and looked at your posts on some of the web pages in other forums and have found you to be the same there. I haven't posted there. Perhaps we can concentrate on the engineering here. Labels are unimportant to me, I strive to concentrate on logic, data, science, and, accuracy.

Thank you for responding to the part I addressed to you.

All engines lacking the crank/flywheel mechanism rely on the atmosphere to reverse the motion. Perhaps a new thread on "crankless" engines should be started for this subject.

The mV of the piston and air, or just the air, over expands the working gas producing a vacuum. That is not "contraction"*. This allows the outside higher pressure to arrest the motion of the piston/air and start back on the return stroke. The working gas begins heating from compression. At some point it becomes hotter than the cold cylinder. Heat begins to flow out into the cold cylinder, (cooling). That increases the acceleration and speed, hence the mV. As the piston/air rushes back in it over compresses the working fluid.

That higher pressure arrests the inward motion of the piston/air, and the cycle begins again. The expansion process reduces the temperature of the working fluid, and eventually below the hot cylinders temperature so it begins picking up heat. That increases the outward acceleration hence the speed, higher mV. Higher mV equates to larger over expansion/compression.

* "Contraction", to me, implies a pulling in by the working fluid. Gases and liquids don't "pull". They only push. I know colloquially "contraction" can mean compression. I won't use it because it is misleading. Mussels contract, solids contract. Fluids do not contract. Gases are compressed by outside forces. Please. "Contraction" is used erroneously by lots of engineers, scientists, and, laymen like myself, but it does make it harder to understand what is going on.

Cooling and heating won't produce expansion or compression to a gas. It is the piston changing volume that does. Or the higher pressure air rushing in, or out, that does. Heating and cooling change the gases pressure. What people are calling "contraction" is a result of lowering the pressure by cooling,or adiabatic temperature drop, and outside forces pushing the volume smaller

Adiabatic temperature change has nothing to do with heat, heating, or, cooling. Definition of adiabatic, without heat/heat transfer.

A cold hole can't be made by a single adiabatic process..no heat is transferred. It requires a complete cycle including heat absorption and rejection, often requiring four distinct processes, ( i.e., Stirling refrigerator.)

[Nobody]

VincentG,

What I get from your last post is that you are exploring the idea that the piston could be induced to move by "overall pressure" or some kind of "kinetic ramming" effect? I would like to inject the thought, descriptive words: bulk or static pressure, verses, dynamic or pulse pressure.

I think the piston may be moved dynamically by both. If one were to get into the fluid dynamics of the air/gas inside the typical engine we have here, it would get very complex very quickly. Sometimes it is better/more-accurate to use a simplification than to model all little details. They may tend to cancel each other out, and the model error will be low enough to use that information to design a fairly good piece of hardware.

Add up the dynamic/pulse-pressure and add it to the base pressure, average the base pressure over the stroke. Use it as kind of an average effective pressure.

[Tom Booth]

Tom,
I would never use that label. I despise that word. It's not as bad as "fake news" but very close. It is an oxymoron. Like saying something is a true-falsehood. I did a search on it. It has been in five posts here. All yours, where you accuse others of using it.

Many of your disparaging comments were deleted by the moderator and you were warned over and over by the moderator and finally banned. An entire thread was deleted (not actually deleted but moved to a junk folder) where you insisted on continuing debating Carnot in your abusive manner. You are the reason editing posts was reduced to just a few minutes, inconveniencing everyone else here, because you would post your abusive and slanderous comments then come back in and edit them.

[Nobody]

P.S.,

Yes. The same Nobody as before. I had to re-register. My account was removed. I don't think it was unintentional. The only reason I'm back is my hope it was accidentally dropped.

[Nobody]

Thanks for confirming it wasn't an accident.

It appears as if you, Tom, are both the moderator and owner here. My discussions here haven't been known to make anyone leave. If anything it has stimulated the discussion and brought in facts and logic. I came back in hopes of communicating with Matt Brown.

I'll retract my stance if you show me where I used it? Or anyone else for that matter?

[Tom Booth]

Thanks for confirming it wasn't an accident.

It appears as if you, Tom, are both the moderator and owner here. My discussions here haven't been known to make anyone leave. If anything it has stimulated the discussion and brought in facts and logic. I came back in hopes of communicating with Matt Brown.

I'll retract my stance if you show me where I used it? Or anyone else for that matter?

First of all, I am not any moderator or forum owner here and have only had very infrequent correspondence or PM with the owner/moderator.

One of your first comments in the forum was to accuse me of posting my "pseudoscience" to every thread, to which I responded here:

I think your misrepresentations and allegations that I (and/or other researchers) am lying, "cherry picking", practicing pseudoscience etc.are not at all justified

There are thousands of topics in this forum for people to post to if they choose, and you and anyone are free to start new threads, new discussions. I've started just half a dozen or so threads over the past ten years, maybe a few more I've forgotten. Your accusation that I'm monopolizing the forum by posting my "pseudoscience" to "every thread" is ridiculous

viewtopic.php?f=1&t=478&p=16493&hilit=P ... nce#p16493

What happened to your post that prompted that response I do not know at this point, either you deleted your own comment or it was deleted or moved to junk by the moderator, but I am certainly not making it up.

Personally your name calling doesn't bother me but the Forum owner did not appreciate the "arguing" and posted warnings which you refused to follow (which I learned through PM with the moderator while discussing deletion of my "Is Science Dead" thread.)

Again, I am not the owner or a moderator but I do value the forum and do try to follow the rules.

[VincentG]

What I get from your last post is that you are exploring the idea that the piston could be induced to move by "overall pressure" or some kind of "kinetic ramming" effect? I would like to inject the thought, descriptive words: bulk or static pressure, verses, dynamic or pulse pressure.

Yes, this is the idea. Although Tom is the one that has mentioned it many times before. I do believe Carnot is wrong, but you cannot prove him wrong with the current math that does not take kinetic energy into account. Go figure!

The effect of air mass is very real, just look to air drag on vehicles, or the way a plane can fly at all. The problem is utilizing this, and I'm not so sure a piston engine can, due to the internal mass of gas compared to the mass of the rotating assembly. Perhaps things get better for pistons when extremely large displacements are used with light weight engine components.

For certain this gets better at much higher charge pressures where the advantage is both increased air mass and delta pressure.

I tend to think the only practical way to take advantage of mass volume is with a lightweight turbine. This is exactly what drives a common turbocharger.

[matt brown]

All engines lacking the crank/flywheel mechanism rely on the atmosphere to reverse the motion.

I know what you mean akin LTD, but might have been better to say ambient or buffer pressure vs simply "atmosphere" (I'm thinking of various free piston schemes, especially outliers like Martini).

A cold hole can't be made by a single adiabatic process..no heat is transferred. It requires a complete cycle including heat absorption and rejection, often requiring four distinct processes, ( i.e., Stirling refrigerator.)

Awesome reduction that requires many years of study to grasp. Kudos for including "often" and "distinct".

Welcome back Nobody. I was out for a few days due to holiday and returned to find things quite lively here (will take me a while to catch up).

I've been doing a deep dive on gammas lately, and as a longtime alpha guy, I never really noticed a weird thing about betas/gammas until now...where expansion occurs on the 'low' side of the cycle, and the engine (itself) is similar a pneumatic motor. As we all know, most heat engine (steam, ICE) run off the high side; any idea of other engines/cycles that run off the low side ?

[Tom Booth]

....

An engine running without heat rejection would allow an over unity machine to be built. That violates the law of conservation of energy, and all of physics would be wrong. All...

...

I'm curious, if that is your view, how do you reconcile or explain the results of the experiment posted earlier in the tread where the engine ran on near boiling hot water for several hours, yet the "heat rejection" top side of the engine remained cool, rather than heating up at all, the temperature dropped a few degrees below ambient.

Generally the surface temperature of every other object on the table had a temperature reading around 66 to 68 degrees F but the top of the engine, which was otherwise insulated, had a temperature reading of 64 or 65 degrees.

Resize_20230708_001810_0021.jpg (76.87 KiB) Viewed 13931 times

Do you believe, for example, that you can have heat "rejection" to an internal regenerator?

[stephenz]

....

An engine running without heat rejection would allow an over unity machine to be built. That violates the law of conservation of energy, and all of physics would be wrong. All...

...

I'm curious, if that is your view, how do you reconcile or explain the results of the experiment posted earlier in the tread where the engine ran on near boiling hot water for several hours, yet the "heat rejection" top side of the engine remained cool, rather than heating up at all, the temperature dropped a few degrees below ambient.

Generally the surface temperature of every other object on the table had a temperature reading around 66 to 68 degrees F but the top of the engine, which was otherwise insulated, had a temperature reading of 64 or 65 degrees.

Resize_20230708_001810_0021.jpg

Do you believe, for example, that you can have heat "rejection" to an internal regenerator?

Hey Tom,

I personally wanted to respond to that video when you posted your response. I got tied up with other things and when I got back the discussion had somewhat drifted. Since you're bringing it back up I'll use this opportunity to formulate my opinion.

Before I do I will say that I respect your efforts to test ideas and document your observations.

Your observations seem to go against the second law of thermodynamics, and that will always upset people and bring condescending comments. That's human nature. Like most people who've studied some level of thermodynamics, a lot of what I learned was just accepted/acknowledged, and I can't really explain why this feels wrong.

I will also not venture into the realm of molecular level discussions which I simple don't have enough of an understanding to participate.

That being said I do have quite a bit of thermal engineering experience on analytical, computational and heavy practical metrology experience. The latter is to me the likely explanation of your observations in this video. Here are a few things that could potentially explain what you observed (in no particular order):

- first, the temperatures you are measuring are really close if not within the error range of the equipment you used
- these devices are not recommended for accuracy, and accuracy is what you need if you are going to present extraordinary observations
- flir type imagers are not well suited to measure temperatures of materials with very different surface types and reflectivity
- use 2-3 surface type thermocouples on the surface of the engine, their accuracy are better than thermal imagery and insensitive to material surface types and reflectivity
- use 2-3 fluid style thermocouples to measure the temperature of the environment in the vicinity of the engine. Measuring the temperature of the solids as a proxy to ambient air temperature is not accurate enough to illustrate your observations. The temperature of the solid will vary much slower than the temperature of the ambient air, so as the air temperature changes over the course of the minutes, the surrounding solids may not have their temperature vary as quickly, thus leading you to possible wrong conclusions
- use a datalogger. There are inexpensive thermocouple loggers that can record up to 8 channels at 10Hz, although you probably wouldn't need a fast sample rate if the goal is to evidence that the cooler has dropped below ambient after some time. But at least the logger would allow you to see how closely related the ambient temperature is to the cooler temperature.

is it something you could try to do?


My personal take on this is that the reported values are incorrect: accuracy? calibration? thermal lag (environment temperature fluctuating faster than the solid temperature references measured)? etc?

As mentioned above my biggest problem with those results is that they suggest:
- the engine is not rejecting heat.
- not only that but because the cooler temperature is lower than ambient, then per second law, the cooler is receiving heat from the ambient air surrounding the engine. (*)


(*) to be clear, as mentioned before I can see how the working fluid could locally and temporarily have possibly a temperature lower than ambient, but I don't think it is possible for the cooler temperature (its surface in contact with the ambient air) to be lower than that of the ambient air.

[Nobody]

Matt,

You are correct. How about if I write it the following way: "Many engines lacking the crank/flywheel and other mechanisms rely on the buffer or outside pressure to reverse the motion."

I will think about other engine cycles that run off the low/cold side power pulses. Can't think of any at the moment.

stephenz,

Good points. I've thought of some of those myself. You laid it all out very clearly. Very difficult to do accurate science.

Tom,

The little LTD's discussed here have very low power capabilities/production. It's quite possible the temperature change is too low to measure. Somewhere recently you said that perhaps some engines heat up the cold side. Perhaps they are just the bigger engines. More power, more heat, higher temperature swing. Easier to measure.