Constant volume compression/expansion-displacer chamber analysis-heat powered mechanical amplifier

[Fool]

Limited was a spell checker error and the word should have been 'liquified'.

This is empirical proof that at standard temperature and pressure gas can't be liquified by pulling a vacuum with free expansion or with adiabatic expansion with work.

[Tom Booth]

Limited was a spell checker error and the word should have been 'liquified'.

This is empirical proof that at standard temperature and pressure gas can't be liquified by pulling a vacuum with free expansion or with adiabatic expansion with work.

Well that makes more sense but is still basically wrong.

It's pretty obvious you just do not know what you're talking about.

Liquefaction by "adiabatic expansion with work" is so much more effective than passive JT valves the JT valves have, (in at least some facilities or applications), been altogether replaced by "wet" expansion turbines that have been designed to handle the liquid discharge.

However, that is a fairly recent development, only about 20 years ago, so maybe you haven't heard about it.

Where you get "at standard temperature and pressure" I don't know. Obviously these liquefaction processes use gas that has been compressed to a high pressure, not STP, but so what?

Cooling to cryogenic temperatures is effected by having the gas expand and do work adiabatically, through an expansion engine or turbine. Including "wet" expansion engines and turbines that discharge the gas in a condensed/liquid state.

Anyway, I think maybe VincentG would like his topic back.

[Fool]

I have no doubt that expansion can be cooled to cryogenic temperatures, it will have very dispersed cooling effects on other masses when that spread out. The point Matt was making is that the pressure will be so low the gas won't liquefy.

The TS chart clearly shows both JT 'cooling' and 'cooling' by adiabatic expansion with work. Neither cross the liquid dome.

You should be asking how to read that on the chart, rather than denying it. science is about better, more detailed, explanations, not denial. Proof is in the mathematics. Denial doesn't enter in any equation.

[Tom Booth]

I have no doubt that expansion can be cooled to cryogenic temperatures, it will have very dispersed cooling effects on other masses when that spread out. The point Matt was making is that the pressure will be so low the gas won't liquefy.

The TS chart clearly shows both JT 'cooling' and 'cooling' by adiabatic expansion with work. Neither cross the liquid dome.

You should be asking how to read that on the chart, rather than denying it. science is about better, more detailed, explanations, not denial. Proof is in the mathematics. Denial doesn't enter in any equation.

You (and Matt) should better educate yourselves regarding where we are at, and what is actually being done industrially in gas liquefaction plants.

Liquifying gas in an expansion turbine is like 100 times more efficient than Joule Thomson expansion and is today, the standard liquefaction method for most, if not all gases.

I don't know where this idiocy about it being impossible ever came from. Some misinformed Wikipedia editor perhaps, but Matt's statements and yours generally are at best, misleading.

In the process of gas liquefaction the gas very often condenses inside the expansion engine or turbine.

A small turbine expanding into a large vacuum (volume) will NOT have liquid whatever forming

I don't know about "into a large volume". Expansion turbines are often very small.

no 'gas' turbine can tolerate liquid, so final 'drip' will always be JT.

I don't know what Matt is trying to say here specifying "'Gas' turbine". An expansion turbine is not a gas turbine. What's the point?

Expansion turbines designed for liquifying gases certainly do have gas liquifying inside the turbine. Sometimes, but certainly not always, a JT valves might also be used.

You guys are both just misinformed, or have some reason for intentionally misinforming others.

I really don't care what you think your charts indicate. If you buy any kind of bottled liquified gas today it was more than likely liquified inside an expansion turbine, no JT valve required.

[Fool]

"You are just misinformed, or have some reason for intentionally misinforming others." Back at you.

If a turbine is used it isn't used for the final liquefaction.

If you insist otherwise, please provide a citation.

There is no doubt that a turbine can liquefy, but they choose not to, and it does only from a high pressure and low temperature point. Not from atmospheric pressure and into a vacuum expansion.

It's obvious you don't care what I think. Your denial of mathematics and science provides you with a lack of caring.

Don't take our words for it. Look it up yourself. Experiment. We just pointed out the obvious from a classical thermodynamics science, hoping you will check it. So far your opinion is baseless.

By the way, how's that butane refrigerator you are building working? Any updates would be appreciated.

[Tom Booth]

...
There is no doubt that a turbine can liquefy, but they choose not to, ...

So you concede.

If you have some reason you want to pursue this further I'd suggest starting your own thread and let VincentG have his back.

[VincentG]

Yes I would appreciate that only because this thread is for experimental results and not just theory.

If you have some reason you want to pursue this further I'd suggest starting your own thread and let VincentG have his back.

[VincentG]

https://youtube.com/shorts/hm1JFVcDG5Q? ... gF5J5ylHTC

A 150cc ltd style Gamma chamber has been constructed for early testing. Results are fantastic for only having mild steel plates. New plates of stainless steel and aluminum will be made. Its performance is already much better than my 60l drum project. This one is almost perfectly airtight.

The chamber is placed directly over an electric stove until the bottom plate has an external temperature of 550F. Ice is placed on the top plate, maintaining an external temperature of around 85F. Unfortunately, water was quickly ingested so the chamber was very wet inside for these test results. The displacer was setup to be spring loaded to the cold plate. The rapid pressure gain actually helps drive the displacer up like a ringbom.

The displacer is multiple layers of high temperature materials and is able to maintain a 500F delta in open air. Unfortunately the steel cold plate does not provide enough cooling power, and the displacer heat soaks while in the chamber. Observed expansion rates suggest actual gas temperatures of 250F Tmin and 500F Tmax. This will improve substantially with an aluminum top plate that will be able to keep the cold side of the displacer cold.

Even at that I saw 50-60cc of expansion, vacuum peaks of over 10inhg and pressures of over 4psi. The air blast is down right aggressive through the 1/8" hole drilled into the outer perimeter of the top plate and it could easily drive a small turbine or vane motor, which I will experiment with.

Performance is equally impressive when using the syringe to add some compression, and like the small epoxy chamber, it will lift a weighted syringe the same distance as shown in the video.

This chamber will be set up with a 100cc glass syringe power piston and the ability to add another identical syringe for up to 200cc pp displacement.

[Tom Booth]

https://youtube.com/shorts/hm1JFVcDG5Q? ... gF5J5ylHTC
...
Unfortunately the steel cold plate does not provide enough cooling power, and the displacer heat soaks while in the chamber. Observed expansion rates suggest actual gas temperatures of 250F Tmin and 500F Tmax. This will improve substantially with an aluminum top plate that will be able to keep the cold side of the displacer cold.
...

Nice work!

Have you had it operating as a working engine yet?

I'm just asking because I would think if mostly just sitting on a red hot stove burner for any length of time, the whole thing will become heat soaked rather quickly.

Without the engine running with ongoing work output all the heat remains heat.

[VincentG]

Have you had it operating as a working engine yet?

Thanks, not yet I'm working on it. I have most of the rotating assembly sorted out but need some parts still. Perhaps you are right. Also, a better bottom plate and a smaller but higher temperature flame will be a better match BTU vs. temperature wise than the huge surface of the stove element.

[VincentG]

More chamber testing was performed and a reverse Ringbom effect was observed. It should have come as no surprised, but the displacer is driven down by low internal pressure just as it is driven up by high internal pressure. When simulating piston movement by hand this has a significant force that should be more than enough to all but eliminate the effective mass of the displacer.

Also observed was when the displacer lowers pressure while the piston is at a simulated BDC, there is an immediate "cloud in a bottle" effect that occurs.

Is this purely detrimental to desired operation? In other words, will this clouding prevent internal pressure from falling as low as it could with completely dry air, and conversely rising as high as it could when heated?

[VincentG]

bump

[Fool]

I'm wondering what would happen if both sides are at room temperature and the displacer was mechanically operated repetitively. would one side get warmer and the other cooler? Would both ends get hotter/warmer and the epoxy center colder/cooler?

What if the same experiment, in a room environment, were started with one side hotter? Would they stay that way, or both slowly become room temperature?

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[VincentG]

I'm wondering what would happen if both sides are at room temperature and the displacer was mechanically operated repetitively. would one side get warmer and the other cooler? Would both ends get hotter/warmer and the epoxy center colder/cooler?
Why would there be any change in temperature at all?

What if the same experiment, in a room environment, were started with one side hotter? Would they stay that way, or both slowly become room temperature?
Why would they not both become room temperature?

[Fool]

The assumption is that the displacer chamber would stay at room temperature or return there.

When a hand powered bicycle pump is used, the bottom gets hotter, and the top stays cool. I don't know if there is any reduced temperature at the top.

The displacer 'pumps' the air back and forth, some adiabatic temperature changes will occur as a result. I'm curious if it is enough to notice, or negligible. I'm also curious, will starting with a delta T effect that. The assumption is not. But I'm curious. Also of effects from cycle speed. Faster more change?

Since the chamber is symmetrical, I would expect each end to be the same temperature, but the middle different. I would call this a pumping hysterias test.

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