Tesla's Ambient Heat Engine revisted

[Tom Booth]

...

..., it all boils down to the fact that expanding internal gas outputs energy. Compressing gas absorbs energy. Both for the entire stroke.

The system, engine, will put out energy during expansion and or absorb it depending on which way the pressure difference is compared with the motion. Higher pressure inside during expansion, energy output. Lower pressure inside during expansion, energy is absorbed, instructor pulling on the piston, energy in.

...

This is what I mean. You repeat the same thing over and over and over and over and over and over and over and over.....

You don't recognize the simple, experimentally demonstrable fact, utilized throughout the world for the liquefaction of gases, that taking energy out of a gas by having it do work causes cooling and CONTRACTION not compression.

You recognize energy must be removed from the gas AS HEAT during compression for the return stroke, to help the gas contract and so be easier to compress, but you don't recognize the same energy can be removed, the same result can be accomplished, by removing energy, by energy output through WORK during expansion, prior to compression.

Without that principle at work we would not have bottled gas, oxygen, nitrogen etc. we would not have propane, bottled natural gas etc they are all manufactured using the Claude liquefaction or similar method. Expanding the gas in an expansion engine or turbine to extract WORK causing the gas to CONTRACT and liquefy.

You prefer to ignore all that and stick with high school level physics. Ideal gas law, kinetic theory and PV diagrams.

Joule and others have demonstrated the equivalence of heat and work. Sorry if you can't comprehend what that means in practice.

Gases "contract". You and others don't think that's possible without removing HEAT. Sorry to tell you but your way behind the times.

[Fool]

To prove gases contract. A plugged syringe at atmospheric pressure, temperature and half full must be put into an ice water bath. After the air cools and the atmosphere pushed, compresses, in the cold gas. Put the bath and syringe into a vacuum chamber and evacuate the air. It will need to stay contracted for proof of contraction. Any expansion means there is pressure inside, no contraction.


A simple brake bleeder suction pump, pressure cooker, and thick glass or acrylic sheet for chamber.

[Tom Booth]

To prove gases contract. A plugged syringe at atmospheric pressure, temperature and half full must be put into an ice water bath. After the air cools and the atmosphere pushed, compresses, in the cold gas. Put the bath and syringe into a vacuum chamber and evacuate the air. It will need to stay contracted for proof of contraction. Any expansion means there is pressure inside, no contraction.


A simple brake bleeder suction pump, pressure cooker, and thick glass or acrylic sheet for chamber.

Nonsense.

Your like a person who doesn't believe water can freeze.

So you say, to prove water can freeze you have to put the ice in the oven. If it doesn't stay frozen then it didn't freeze.

[Fool]

Then you also can't prove contraction, since the experiment proves pressure. Contraction and pressure are opposites. If one exists, the other can't. There is always pressure, even the vacuum of space has a ever so slightly positive pressure.

Putting ice in the oven does prove freezing. Ice melts when put in an oven. To prove that ice isn't frozen water it would have to not melt.

[Fool]

Here is another test. Fill a syringe with air. Place it in a vacuum. Measure the pressure by seeing how much weight it takes to depress it slightly. Cool it. See if it contracts. Measure again to see how much weight it takes to compress it the same small amount. Prediction: Nine tenths (9/10) (340 K to 306 K) the temperature nine tenths the weight. Zero contraction, always a positive pressure.

Let it expand with work, it will get colder, but the pressure will always be positive. Let water vapour condense, lower pressure yet, but still positive. Put a sealed crushed, by water condensation, can, in a vacuum and the positive pressure from the water liquid will inflate the can. Use a balloon or Ziploc bag.

What you think is contraction is really compression by atmosphere.

[Stroller]

Kindly take your friend "fool" and get lost.

Tom, please don't despair. Stroller appears to be a kind and knowledgeable experienced person whom I don't know or collaborate with. I'm sure that we could have a great time talking shop.

Good to meet you and thanks for your patient contributions here.

Work is the easiest to measure. All that is needed is RPM and torque. RPM is easy, torque requires a spring, arm, pivot, and, brake or propeller. And a way of calibrating it. Alternately a generator and voltamp meter could suffice.

I pointed out that this is the main thing lacking from Tom's experiments too. Difficult to do on tiny LTD engines. I agreed with his hypothesis that work extracted from the system cools the working fluid. What he doesn't seem to appreciate is just how little work is being extracted in comparison to the energy throughput. I also pointed out how little energy is required to overcome bearing friction and maintain flywheel momentum, Tom is positing friction between graphite piston and aluminium power cylinder as the cause of the ~6K T difference between those components and the top plate, and as additional "work done". Ad hoc hypotheses always come with problems though: this (mostly fictional) frictional "work done", is reducing heat loss from the working fluid he claims that the "work done" is cooling down.

[MikeB]

If that is truly the case, then the gas laws imply that the temperature of the fluid must also be equal, everywhere.
This is another case where it helps to think of energy flow into the engine, rather than heat.

Glad when you chime in Mike B. I think this ties in nicely with your thoughts on "average temperature". The position of the displacer affects the average air temp, and therefore the average pressure.

But if we were to analyze a snapshot in time, I don't believe the gas is really the same temperature above and below the displacer.

I'm trying to be open-minded about everything, so I definitely don't believe _anything_ about temperature distribution yet.

That is one of the issues with these thought-experiment discussions - one can only really describe discrete steps, and that really isn't what's happening in a real engine. And of course every design will be a little different in how it behaves.

So, anyway, what I was trying to get at was a better understanding of how heat/pressure/energy flows within the working fluid. As you say, we have this core issue of having it in contact with both the hot and cold ends simultaneously, but with an expectation that one end will have more effect in one part of the cycle, and the other more effect at the 'opposite' point.

[Fool]

Scientific studies have found 'belief' to be unreliable and has zero effect on experimental outcomes. Please don't take my word for that. Take meticulous data. Scientific/mathematical rigor is the only thing that will expose error.

Even if a small amount of gas remains in the cold side of the engine during expansion, thus getting colder than the cold plate and cooling it slightly, when much warmer gas and larger mass is flowing out of the regenerator it begins warming the cold plate by a higher total energy transfer. That as VincentG has pondered is a potential for local cold spots, and as MikeB has pondered, an overall average bulk higher temperature. Very good you guys. The difficulty of sorting that out, from a single inexpensive hand waving of an inexpensive thermal camera, because obvious. The average bulk temperature is what the engine reacts to. Any pressure sensors will react similarly to the engine, so it is a fair representation to use for analysis. The sensor will react as fast or faster than the engine.

[Tom Booth]

...

I'm trying to be open-minded about everything, so I definitely don't believe _anything_ about temperature distribution ...

One thing that is fairly obvious.

Atmospheric pressure across the entire globe varies very little from 14.7 psi

By comparison air temperature can vary quite markedly, even within a very small region. The shady vs. sunny side of a wall for example, or the interior of an oven or ice box. Variations in pressure require air tight containment to keep high and low pressure from equalizing, vacuum chamber or high pressure air tank, different temperature air, near a wood stove for example, may actually tend to separate do to differences in density. The hot air rising to the ceiling in a room.

In other words, the pressure has a much greater tendency to equalize. Different temperature air can be kept separated much more easily independent of pressure.

[Administrator]

....

[Tom Booth]

...
Work is the easiest to measure. ... Alternately a generator and voltamp meter could suffice.

I pointed out that this is the main thing lacking from Tom's experiments too.

As anyone who's been here any length of time, I've been running generators and using volt meters and amp meters when appropriate or needed.

Difficult to do on tiny LTD engines.

No it isn't. It's perfectly simple. I do it frequently. I think you've seen me using the volt meter in my videos.

I agreed with his hypothesis that work extracted from the system cools the working fluid. What he doesn't seem to appreciate is just how little work is being extracted in comparison to the energy throughput.

What you don't seem to realize is your assumptions are wrong and the truth is just the opposite. The HEAT throughout is virtually or actually non-existent. The work output is all there is.

I also pointed out how little energy is required to overcome bearing friction and maintain flywheel momentum, Tom is positing friction between graphite piston and aluminium power cylinder as the cause of the ~6K T difference between those components and the top plate, and as additional "work done". Ad hoc hypotheses ...

Nothing Ad hoc about it.

..always come with problems though: this (mostly fictional) frictional "work done"

And what exactly is your basis for suggesting the friction is "fictional". Or are you suggesting friction is not from the gas expanding and doing "work" or what exactly do you suppose is the cause of the heat at the power piston?

, is reducing heat loss from the working fluid he claims that the "work done" is cooling down.

Hardy har har.

I'm not sure that last portion of that sentence actually makes any sense.

this (mostly fictional) frictional "work done", is reducing heat loss from the working fluid he claims that the "work done" is cooling down. :laugh

"The "work done" is cooling down" is certainly not anything I said. That makes no sense.

The expanding gas does work driving the piston, turning the flywheel, making the engine go round and round.

This motion of the engine that results from the gas doing work, ultimately results in friction. The work transforms into motion and back into heat.

Hardy har har..

You said above: "I agreed with his hypothesis that work extracted from the system cools the working fluid".

Well do you really? Because now you're portraying it as something laughable to joke about. So which is it.

You seem to be contradicting yourself.

The "work done" is not "reducing heat loss" it's converting heat into work.

The work is causing motion

The motion produces friction.

Friction produces heat.

The heat is mostly dissipating to atmosphere, but some portion is likely conducting back to the plate somewhat counteracting the cooling. Cooling that is the result of the gas doing work and loosing internal energy.

[Tom Booth]

Say I'm wrong.

Regardless, it appears that something , friction, pressure, or some unidentified mystery force is elevating the temperature around tbe piston/power cylinder while the top cold plate appears to remain cool.

If the power piston were further away from the top plate, possibly my theoretical cooling via work output would be more discernable with this apparent power cylinder associated heat source at arms length so to speak.


And so:

Compress_20240505_164820_0963.jpg (35.77 KiB) Viewed 3097 times

Package tracking indicates it may arrive much sooner than anticipated. Probably before the end of the week.

This video strikes me as something of a put on. The guy can't really be serious. But after seeing several of my own engines apparently 'freeze up", cool themselves below the "sink" temperature, re-freeze melting ice, apparently run without "rejecting" any measurable heat etc.

Maybe what he says should be taken seriously.

What I find interesting is that when he first places the engine on the ice it is pretty obviously sliding around because the surface of the ice is wet and slippery.

After the engine runs for a minute though, the engine stops sliding around, and when he picks up the engine, the ice sticks to the bottom, lifting up with the engine.

https://youtu.be/L6Jmdve1JK8

Well, adhesion is a probable explanation. Just a suction cup kind of action keeping the ice adhering to the engine.

If I had not experienced something similar myself, I'm quite sure my engine has stuck to the ice because the wet surface of the ice re-froze on the bottom of the engine. And continued to do so for at least 20 minutes, over and over again.

https://youtu.be/2b2dIR8Eql8?si=vs0enXmxQ7P3Z0xb

In that video, you see the third time in a row that this re-freezing had taken place. After uploading the video the engine eventually got "stuck" to the ice again.

However, whenever the engine was removed, the ice would start melting. The surface would become wet and the engine would slide around on the wet surface.

A few minutes later it would be "stuck" again.

Anyway, whatever was going on, there is no doubt that ambient heat would eventually melt the ice, as the insulation is not perfect.

But with two of the above engines running on ice, the ambient heat has no way to get to the ice except through one engine or the other.

If the engine is REALLY cooling the cold plate even a fraction of one degree, with no heat getting to the ice, at a minimum the ice should take a very long time to melt.

Some heat might still get to the ice through the perimeter outside edges of the cold plates, but probably not much.

[Stroller]

The average bulk temperature is what the engine reacts to. Any pressure sensors will react similarly to the engine, so it is a fair representation to use for analysis. The sensor will react as fast or faster than the engine.

The theoretical pressure change due to volumetric change in an unheated engine turned over by hand is easy to calculate and plot. That could then be used to calibrate a pressure sensor set into the engine. Then if pressure is sampled at a high rate in the running engine with heat applied, the volumetric change due to mechanical compression could be subtracted from the data obtained. We could then derive the difference between Th and Tc from the max and min pressures obtained.

I've been looking for an affordable datalogging pressure sensor online - no luck yet... Any suggestions or links?

[Tom Booth]

The average bulk temperature is what the engine reacts to. ...

...

Just curious but what do you define as "average bulk temperature".?

And in what way does the engine react to the "average bulk temperature".

Do you perhaps mean the thermocouples "reaction" due to slow response time?

Let's say you have a cold plate at 0°C (ice) and a hot plate at maybe 1000°C (some flame heat source)

Is the "average bulk temperature" 500°C ?

How does the engine "react" to such an average?

Maybe this would be clearer in context?:

Let's see:

meticulous data. Scientific/mathematical rigor is the only thing that will expose error.

Even if a small amount of gas remains in the cold side of the engine during expansion, thus getting colder than the cold plate and cooling it slightly, when much warmer gas and larger mass is flowing out of the regenerator it begins warming the cold plate by a higher total energy transfer. That as VincentG has pondered is a potential for local cold spots, and as MikeB has pondered, an overall average bulk higher temperature. Very good you guys. The difficulty of sorting that out, from a single inexpensive hand waving of an inexpensive thermal camera, because obvious. The average bulk temperature is what the engine reacts to. Any pressure sensors will react similarly to the engine, so it is a fair representation to use for analysis. The sensor will react as fast or faster than the engine....

(Emphasis added)

Is that enough context?

Nevermind. That was part of fools ongoing attempt to hand wave away the temperature readings of my thermal imaging gun I guess:

This one:

Compress_20240504_125427_7507.jpg (22.73 KiB) Viewed 3078 times

Or maybe this?:

Compress_20240508_133713_3920.jpg (16.93 KiB) Viewed 3078 times

Or both I suppose.

An effective regenerator, in reality, "holds back" and returns to the hot side some 95% of the heat.

To accommodate the regenerator in that experiment, the displacer had to be reduced in diameter about 3/8" which would also reduce the volume of air. So... to talk about the "...much warmer gas and larger mass ... flowing out of the regenerator" while during the heating cycle the cold air is pushed down through the regenerator, away from the cold side, the bulk of the large mass of hot air is directed to the hot side while the cold side is insulated from this heat by the displacer.

But I suppose any inaccurate, made up off the top of a "fools" head nonsense is good enough to pass off as "scientific rigor" when it comes to dismissing actual instrument readings that happen to conflict with predetermined died-in-the-wool "established science" with a 200 year history, (but zero actual experimental data to back it up.)

Of the dozens and dozens of experiments I've conducted in an effort to demonstrate the validity of the Carnot limit postulates, such as 90% "waste heat" flowing freely out through the cold plate etc. Results have consistently shown nothing of the sort.

The only heat passage is through conduction or convection or radiative channels that bypass the working fluid.

The working fluid itself, although quite obviously taking in heat, by the time the working fluid expands and is moved over to the cold side it has already dropped in temperature becoming as cold or colder than the "sink" temperature.

Theoretically nearly 100% of the heat may be converted to work with the expansion stroke.

Contrary to the scenario spun by "fool", the combined movement of the displacer shifting the working fluid between the hot and cold side through the regenerator and the heat retaining action of the regenerator itself prevent the heat from reaching the cold side even if it were not all "used up" or converted to mechanical "work" output

[Tom Booth]

The new meter and thermocouples arrived today

Compress_20240512_125355_5025.jpg (39.2 KiB) Viewed 3070 times

For the experiment, when the engines arrive, I won't be posting to this thread though. As I don't think that is what Matt started the thread for. There is a previous thread where this experiment was first proposed I may resurrect, or just start a new one.

Anyway, with my old meter and this one, it will be possible to get up to eight simultaneous thermocouple temperature readings, supplemented by the thermal imaging camera.