Experimentally confirming the conversion of heat energy to work

[VincentG]

It is universally accepted in physics and science generally that at least SOME heat can be converted into work. The only real question is how much. If you accept the Carnot limit that's one thing but you seem to think your device being spun up by a Dremel tool has overturned even the Carnot limit. You say no heat at all is converted.

No, the video was just a demonstrationof how fast the gas can be heated and cooled. There is no real work being done, just a visual representation of the pressure and temperature swing.

You do realize you are going against accepted science at least as much if not moreso than me in just questioning the "limit". but in the opposite direction.

Yes, unfortunately lol.

Anyway, I don't really see anything very extraordinary in your demonstration. You seem to be seeing what you want to see. Or, maybe I am and your just being objective, but your results can be interpreted differently, just as my so-called "results" with my LTD "toy".

As it relates to the subject of this thread, I have no experimental proof as of yet. I brought the video into the discussion to counter your argument that isothermal heating and cooling must be or is slow.

[Fool]

Perfect description. My contention would be that with less impacts, the effective temperature is essentially lower.

Energy verses velocity. If masses are doing 100 mph and are caught by a second mass eventually the second mass will be doing 100 mph and will no longer speed up from the 100 mph masses. If the second mass is very very small, negligible, compared to the 100 mph masses, only one being caught will cause 100 mph speed in the second mass.

The same is true of a thermometer. If the thermometer has a much much smaller mass than the gas molecule, only one hitting it at 1000 degrees will have it reading 1000. If it's more massive, it will take more molecules to bring it up to 1000 degrees. The 1000 degrees molecules will no longer increase its temperature. The thermometer will send the molecule back out with the same temperature/speed it had before the collision.

I'd still reserve judgement until someone does the actual experiment.

It seems pretty extraordinary if actual heat can be "disappeared" by lifting a weight.

It's always good to be skeptical of other's experiments. It's always fair to redo any experiment, especially when learning. Learning from other's experiments is time and money saved. I think there are similar enough demonstrations that my skepticism is low.

I really have no doubt that if I were to repeat your experiments, I would see similar data. I would like to repeat them while measuring additional data.

The energy for lifting a weight must come from somewhere. I find it reliable to think it is converted from somewhere, not "appearing" or "disappearing ". Thermal internal energy is one place. Heat poring into a semi isothermal expansion is another.

I suppose a "semi isothermal" expansion is the same as a "quasi adiabatic" expansion? Heat transfer and temperature drop are factors of both. The same for compressions.

Still not sure. I think it's whatever would raise the temperature of the room.

Adding energy to the gas in the room will raise the temperature and pressure of the gas in the room.

This is in contrast to another description I have read, that the fire piston has the same internal energy at "TDC", just bunched up in a smaller space, manifested as higher temperature.

What happened to all the work energy added by force and distance the "human arm" put into the plunger? That is concentrated at the bottom too.

[VincentG]

The same is true of a thermometer. If the thermometer has a much much smaller mass than the gas molecule, only one hitting it at 1000 degrees will have it reading 1000. If it's more massive, it will take more molecules to bring it up to 1000 degrees. The 1000 degrees molecules will no longer increase its temperature. The thermometer will send the molecule back out with the same temperature/speed it had before the collision.

Its all relative right?

What happened to all the work energy added by force and distance the "human arm" put into the plunger? That is concentrated at the bottom too.

It's stored in the increased pressure. And perhaps the root of Tom's argument for the liquefaction of air.

[Fool]

Relative? LOL Yes I suppose. Temperature is like a speed limit measures the speed of cars. Number of cars is like the total energy, how many it takes to fill a parking lot. Wattage is like the time it takes to fill the parking lot at that speed and density. Speed and density are current.

Without that work energy being compressed into the pressure at the bottom there would be no energy of compression. The atmospheric air at the top would just sit there. It needs to have energy supplied by a push. Furthermore, pushing slowly, and holding won't light the paper. It becomes a factor of work energy input per time. Watts. Same amount of energy, slow or fast, higher wattage. Also, the energy is built up in the gas before the temperature difference causes enough heat flow to cool it.

[Tom Booth]

Tom, like Fool said the compressed air expansion is leaving out part of the cycle. If the air compressor was in the same room, temperature would be greatly affected.
...

"Greatly"?

I don't think so. At least not in terms of work vs no work.

As I already pointed out. So the compressor runs on electricity and adds heat to the room. It does so equally for both the work and no work situation.

You still have the same situation for the "experiment" doing work and the "control" not doing work.

Again just a stupid, unjustified excuse to dismiss the whole thing.

The only difference would be the expanding air escaping the tank either doing work and (theoretically) cooling from conversion of heat into work or not doing work and only, maybe cooling a little from Joule thomson expansion.

The compressor in the room is no different in either case. That objection is just more BS IMO, as if the question is unanswerable.

Nonsense. Do an experiment and stop making excuses if you're really interested it proving anything one way or the other.

[Tom Booth]

.... I brought the video into the discussion to counter your argument that isothermal heating and cooling must be or is slow.
...

Just the same, I see no indication of any "isothermal" anything in that video.

[VincentG]

Without that work energy being compressed into the pressure at the bottom there would be no energy of compression. The atmospheric air at the top would just sit there. It needs to have energy supplied by a push. Furthermore, pushing slowly, and holding won't light the paper. It becomes a factor of work energy input per time. Watts. Same amount of energy, slow or fast, higher wattage. Also, the energy is built up in the gas before the temperature difference causes enough heat flow to cool it.

So the same input energy could drive the piston faster(less net pressure after cooling) or slower(more net pressure after cooling).

Which is more efficient at what? Lol. Btw this whole discussion is a tangent brought on by Tom's questioning my very simple original question.

[VincentG]

Again just a stupid, unjustified excuse to dismiss the whole thing.

The only difference would be the expanding air escaping the tank either doing work and (theoretically) cooling from conversion of heat into work or not doing work and only, maybe cooling a little from Joule thomson expansion.

The compressor in the room is no different in either case. That objection is just more BS IMO, as if the question is unanswerable.

Nonsense. Do an experiment and stop making excuses if you're really interested it proving anything one way or the other.

I have burned myself on a compressor a few times. It will make a big difference if you are compressing gas in the same room as you expand it in. If you doubt that than I question your judgement.

I do plan on an an experiment with my 60l drum build. It should be large enough to gather much more concrete evidence for either case. It could well be that Tom Booth is right and 100% of heat energy is converted to work.

My point is simply, can someone show me a similar experiment?

[Tom Booth]

Again just a stupid, unjustified excuse to dismiss the whole thing.

The only difference would be the expanding air escaping the tank either doing work and (theoretically) cooling from conversion of heat into work or not doing work and only, maybe cooling a little from Joule thomson expansion.

The compressor in the room is no different in either case. That objection is just more BS IMO, as if the question is unanswerable.

Nonsense. Do an experiment and stop making excuses if you're really interested it proving anything one way or the other.

I have burned myself on a compressor a few times. It will make a big difference if you are compressing gas in the same room as you expand it in. If you doubt that than I question your judgement.

...

Nobody is disputing that running a compressor creates heat. But so what?

As I suggested originally, run the compressor outside if you like, it makes no difference.

You're running two experiments.

One releasing air from the tank not using the air to do any work. Just expanding the gas, releasing it from the tank. That tells you how much cooling there will be from expansion alone.

Two, run a second experiment in exactly the same way. Same compressor, same room, same tank, but this time you use the air to drive an air motor and do your work lifting weights or whatever work you choose to have the gas do.

If you run the compressor outside the first time run it outside the second time. You aren't running the compressor during the experiment anyway.

If you run the compressor inside the first time do the same the second time. Just let the temperature of everything equalize before starting the experiments.

Your only testing how the compressed air cools when doing work or when not doing work.

If the gas expanding while escaping the tank gets colder while doing work then it did not foi g work, then there is your evidence that gas expanding and doing work converts heat (or "internal energy" to keep FOOL happy) into work and causes more cooling than when not doing work.

The compressor running before the experiments to fill the tank, inside outside, it makes no difference.

Get the tank filled at the air pump down at the corner garage, who cares?

[VincentG]

Well, the title of the post is experimental, so I will try to experiment. I still think you are discounting the energy it took to compress the gas, and that the ACM takes advantage of infinite ambient cooling.

Thats the whole point of the smaller room thought experiment. The apparent "cooling" is maybe just a redistribution of temperature, and not an absolute reduction of internal energy.

[Tom Booth]

Well, the title of the post is experimental, so I will try to experiment.

Great!

I still think you are discounting the energy it took to compress the gas,

I'm aware it takes energy to compress the gas, but there is nothing about that that needs testing afaik, is there?

and that the ACM takes advantage of infinite ambient cooling.

It does, to pre-cool the compressed air before it does the work driving the turbine, where it gets much colder.

The whole point of having the gas. DO WORK through driving the turbine is to convert heat into work to take the heat out of the air.

Yes the air would get cold by compressing the gas and cooling the compressed hot gas with ambient air and then expanding the gas. But as pointed out over and over with at least half a dozen references already, the gas gets MUCH much colder if it is also made to do additional work while expanding.

That's the whole point of the smaller room thought experiment. The apparent "cooling" is maybe just a redistribution of temperature, and not an absolute reduction of internal energy.

Of course.

So you do one experiment. Let the compressed gas expand and see how cold it gets from "just a redistribution" without doing any additional work.

Measure the temperature.

Then start all over, exactly the same way, doing everything exactly the same, but the second time as the gas is released, let it out through an air motor that is driving a generator or something, to do additional work.

That way you isolate the one variable you want to test for. Doing additional work or not doing additional work.

Supposedly the heat in the gas will basically be transformed into the electricity coming out of the generator. Or put another way, the gas needs to draw on its "internal energy" to push the air motor around and round so the air motor can drive the generator.

As a result of the expenditure of "internal energy" driving the air motor as it expands, the gas is supposed to get much colder than it did in the first experiment where it is allowed to just expand freely without doing anything more.

The additional work of driving the motor/generator takes more energy out of the gas, and as the only measure of internal energy for a gas is temperature, the less internal energy remaining in the gas the colder the gas gets. The more "work" the gas does, the colder it gets.

I can only assume this actually works since there is this multinational corporation using such a process (on steroids) that has been quietly selling liquefied gases all over the world since 1902.

[Tom Booth]

It is kind of interesting but also somewhat frustrating, that a company going by the name Air Liquide with over 800 videos on their YouTube channel has virtually nothing at all about the Claude process itself or how air is liquified in general. Nothing on the website either. A little history.

It's all about business. Acquisitions, mergers, stockholders, corporate assets, etc.almost nothing whatsoever about the process or the science of liquifying air.

https://m.youtube.com/@AirLiquideGroup/videos

I could only find one video about the distillation process, after the air is initially cooled and liquefied, but nothing about the liquefaction process itself, the Claude process, or any other.

One thing I learned is that Air Liquide had acquired the American company AirGas some time ago.

https://youtu.be/sp9CpvWHGgE

[Fool]

Claude's process

Air can also be liquefied by Claude's process in which the gas is allowed to expand isentropically twice in two chambers. While expanding, the gas has to do work as it is led through an expansion turbine. The gas is not yet liquid, since that would destroy the turbine. Commercial air liquefication plants bypass this problem by expanding the air at supercritical pressures.[1] Final liquefaction takes place by isenthalpic expansion in a thermal expansion valve.

[VincentG]

Maybe for further discussion I should define the room as 10'x10'x10'.

Now any continuous air expansion can't take advantage of an infinite buffer space to expand into, causing the pressure in the room to rise like Fool suggested.

I know Tom will take issue with this and say I am adding more and more restrictions, and it may seem that way, but this was the original thought of the experiment, a small room.

Then heat energy is supplied to the engine so that measurements of Qin, Qout, and work are taken.

[Tom Booth]

Claude's process

Air can also be liquefied by Claude's process in which the gas is allowed to expand isentropically twice in two chambers. While expanding, the gas has to do work as it is led through an expansion turbine. The gas is not yet liquid, since that would destroy the turbine. Commercial air liquefication plants bypass this problem by expanding the air at supercritical pressures.[1] Final liquefaction takes place by isenthalpic expansion in a thermal expansion valve.

What's often given rather short shrift is "While expanding, the gas has to do work as it is led through an expansion turbine".

This was the major advance over the Linde process using only a throttling valve. In the Linde process the gas cools slightly expanding through just an expansion (or throttling) valve but does not do any work as it expands other than the work of pushing itself out of the way. As some gas goes through the valve more gas expanding behind it has to do a little work pushing the gas in front of it along. But because the cooling was very slight, just a degree or two, the cycle had to be repeated over and over. The gas passed through the valve many many times before it would finally begin to liquify.

Claude's major advancement was mostly simply just to replace Linde's expansion valve with an expansion engine.

This forced the gas to do much more work as it expanded. To escape from the compression the gas now had to drive a piston to run an entire engine, not just push some gas molecules out of the way. The engine also powered other things giving the gas additional work so it cooled much more rapidly and liquified much more quickly.

Infact it worked so well, it actually worked too well. The gas would liquify inside the cylinder, getting so cold so fast the engine itself would freeze up.

More cold tolerant lubricants were used, but the air might actually freeze solid.

So eventually it was found that by using a less efficient expansion engine the air could be brought down near to the liquefaction temperature quickly in the turbine by making the gas do work, then the process could be finished by the Lind method.

Fool likes to pretend that he knows what he's talking about, previously insisting the gas cannot liquify in the turbine. He hasn't studied the whole history from the begining.

It is not the gas cannot liquify in a turbine, it's that when it does the turbine will wear out quickly and turbines are expensive. So they now use the turbine for very rapid cooling and finish the liquefaction process using the expansion valve for the last few degrees of cooling, since there is nothing much to damage in a simple valve.

The advantage of a turbine over an expansion engine is obvious. Turbines are more efficient.

Another advancement was,

Well, if the turbine or expansion engine doesn't really work as well, unless it is powering a load, if it needs some actual work to do, it is costing a lot to run the compressor to compress the air. Let's just use the expansion engine to run the compressor!

And so the turbo-expander was born.

A compressor and expansion engine coupled together on the same shaft. The compressor compresses the gas so it can do work expanding and cooling as it escapes through the expansion engine doing work, and the work it does is to drive the compressor. So now the expanding gas is doing the work of compressing additional gas to be expanded. Quite a system.

Such a "bootstrap" system is the standard method I think these days.

I've been told that the public information about the efficiency of the energy recovery of these bootstrap systems is greatly watered down.

Wikipedia articles state that the expansion turbine only recovers about 10%

I've been told privately (in a phone conversation with Peter Lindemann) that the energy recovery using turbo-expanders is actually much closer to 100% (above 90% as I recall).

So, converting heat into work has moved well beyond the "experiment" stage.

All kinds of major MAJOR industrial processes going on RIGHT NOW today depend on it.