Experimentally confirming the conversion of heat energy to work

[Tom Booth]

Being alternately heated and then cooled about 50 times per second? The temperature remains constant?

[VincentG]

Yes, ideally the temperature graph would look like a square wave.

You have to remember that the chamber is only 15cc, has no dead space, and has a large heat exchanger area to volume ratio that keeps the gas in close proximity to the plate exchangers, and can full "switch" the heat source on and off.

This is in large contrast to most other designs.

Look at the video and tell me your version of what is happening.

[Tom Booth]

Yes, ideally the temperature graph would look like a square wave.

You have to remember that the chamber is only 15cc, has no dead space, and has a large heat exchanger area to volume ratio that keeps the gas in close proximity to the plate exchangers, and can full "switch" the heat source on and off.

This is in large contrast to most other designs.

Look at the video and tell me your version of what is happening.

To me that piston looks proportionately quite large and heavy, compared to, say a common graphite piston.

So I see a slight but noticeable delay after heating and cooling, (the displacer moving up off the bottom or down from the top)

The delay or pause IMO would be due to the inertia of the piston, as well as it's momentum.

The piston would not stop it's motion in either direction (before the displacer changes direction and moves) unless met with resistance. That resistance would be the compression of the working fluid from the pistons momentum on the down stroke and expansion on the up stroke.

Anyway I don't know what your basis for saying the temperature is ever constant could be.

As the temperature goes up, it takes a moment to overcome the inertia of the piston.

I think the pressure and temperature are probably changing constantly.

[VincentG]

To me that piston looks proportionately quite large and heavy, compared to, say a common graphite piston.
Larger and heavier than I'd like, but it's what I had to work with.

So I see a slight but noticeable delay after heating and cooling, (the displacer moving up off the bottom or down from the top)
Yes.

The delay or pause IMO would be due to the inertia of the piston, as well as it's momentum.
Again, yes.

The piston would not stop it's motion in either direction (before the displacer changes direction and moves) unless met with resistance. That resistance would be the compression of the working fluid from the pistons momentum on the down stroke and expansion on the up stroke.
No, it stops when internal pressure equalizes with external pressure

Anyway I don't know what your basis for saying the temperature is ever constant could be.
Constant is a relative term in a dynamic situation.

As the temperature goes up, it takes a moment to overcome the inertia of the piston.
Yes.

I think the pressure and temperature are probably changing constantly.
IMO, not when the power pistonis seen at rest.

[Tom Booth]

...
I think the pressure and temperature are probably changing constantly.

IMO, not when the power pistonis seen at rest.

OK, that's your opinion. I still don't see the point as "at rest" has what to do with expansion and contraction?

There is no "at rest" isothermal or adiabatic anything, I don't think, is there?

Also, as I said, the piston has weight and inertia that resist being moved even while the temperature and pressure are rising or falling.

But opinions about what either of us thinks we see in a slow motion video has what bearing on this topic?

Does our subjective perceptions "confirm" or refute the conversion of heat into work one way or the other?

But just for example, the space shuttle appears to be "at rest" or not moving even after the rockets fire. There is plenty of heat and pressure, but the rocket takes time to lift off due to inertia. The blast of flame out the rocket however is not "isothermal" just because the rocket has inertia

But either way, so what?

[Tom Booth]

The piston would not stop it's motion in either direction (before the displacer changes direction and moves) unless met with resistance. That resistance would be the compression of the working fluid from the pistons momentum on the down stroke and expansion on the up stroke.

No, it stops when internal pressure equalizes with external pressure

...

I Missed most of your italics.

What makes you think "equalization of pressure" is going to stop anything.

Newtons laws of motion.

If you roll a ball down a bowling alley does it stop when the air pressure on both sides is equal?

If that were the case nothing would ever go anywhere

No the piston stops, not when the pressure is equal, but when the pressure builds up enough from compression to counteract the momentum of the piston. "Equal" pressure has no effect at all.

With expansion, again, the piston isn't going to stop at "equal" pressure either. The pressure would have to drop enough below outside atmospheric pressure (plus gravity in that arrangement) enough to overcome the momentum of the piston.

[Tom Booth]

As the temperature goes up, it takes a moment to overcome the inertia of the piston.

Yes.

I think the pressure and temperature are probably changing constantly.

IMO, not when the power piston is seen at rest.

The last two responses here seem to contradict each other.

The temperature goes up but it doesn't ?

[Tom Booth]

I guess what you are saying is because you are applying cold with ice, the ice is removing heat allowing the piston to return.

From my point of view, the ice only needs to cool the working fluid to get the engine started.

From there, (cold gas) ambient heat is added, the gas expands and does work, in the process looses energy and returns (cools back down and "contracts".

The viewpoint you have adopted says basically that heating and cooling causes all the action.

I'm thinking on the other hand that it is the work output that causes the cooling and contraction of the gas and the return of the piston. After the first revolution or two the ice is almost redundant acting only as a kind of insulation. Infact, experimentally, insulation seems to have an effect similar to ice.

That is, if you get the engine running on heat and then insulate the "cold" side the engine starts running better. I'm saying, once started, the engine cools itself by converting heat into work so insulating the cold side doesn't keep heat in or prevent heat from escaping, the insulation keeps heat out so the engine can cool itself more effectively.

It's what I first theorized back in 2010:

viewtopic.php?t=478

But never tried to test the idea experimentally until just a few years ago.

Surprisingly the experimental results seem to confirm the theory, as crazy as it may seem to be.

Ice is just a very good insulation that allows the engine to cool itself and operate at a greater ∆T, but NOT due to the ice taking heat away. It just prevents heat from going in.

At least that the way it seems, or what my experiments seem to show.

[Tom Booth]

BTW, if you read the first few posts on that thread: Stirling engine thermodynamics: viewtopic.php?t=478 I provide several references to the effect that a gas cools down when made to do work. The more work it does the more it cools down.

Is this method of cooling and liquifying gases not evidence of heat being converted into work on an industrial scale?

[VincentG]

I guess what you are saying is because you are applying cold with ice, the ice is removing heat allowing the piston to return.

Yes, exactly. I understand your position, but I'm saying that this way works too. And in the video, there is really no work being done.

Also, I specifically used a low temperature delta to reduce the piston stroke and minimize the effects of inertia. An even lighter piston would be beneficial and maybe I can make that happen.

[VincentG]

BTW, if you read the first few posts on that thread: Stirling engine thermodynamics: viewtopic.php?t=478 I provide several references to the effect that a gas cools down when made to do work. The more work it does the more it cools down.

Is this method of cooling and liquifying gases not evidence of heat being converted into work on an industrial scale?

I've read the whole thread. No, I don't think its the same thing. A heat pump style mechanism(or air cycle machine) clearly converts work to a temperature difference.

Drive vs. driven as Matt Brown would say.

[Tom Booth]

BTW, if you read the first few posts on that thread: Stirling engine thermodynamics: viewtopic.php?t=478 I provide several references to the effect that a gas cools down when made to do work. The more work it does the more it cools down.

Is this method of cooling and liquifying gases not evidence of heat being converted into work on an industrial scale?

I've read the whole thread. No, I don't think its the same thing. A heat pump style mechanism(or air cycle machine) clearly converts work to a temperature difference.

Drive vs. driven as Matt Brown would say.

Well, you can think whatever you want, but cooling a gas through "making it do work", converting heat into work is not the same thing as a heat pump. A heat pump only moves heat from one place to another.

Converting heat into work is not the same thing as moving heat.

An air cycle machine that in part cools by making the gas do work turning a turbine is also not the same thing as a heat pump. A heat pump only MOVES heat by using a phase change to absorb heat in one place and give heat out in another. A heat pump does not convert any heat into work.

An air cycle system takes heat out by making the gas do work turning a turbine to generate electricity, or do some other work. The heat is not MOVED, it doesn't reappear somewhere else. At least not unless the electrical output is used to run an electric heater.

Anyway, IMO there is ABUNDANT experimental evidence going back, at least to Joule that heat can be and is very commonly converted to work.

Actually "converted" is just a manner of speaking. Heat is motion of molecules. "Work" is motion. Energy transfer is a transfer of motion. So the motion of the "heated" gas is transfered to the motion of the engine and it's load, spinning wheels or whatever. When the gas transfers it's motion to the engine the gas has less motion. With less motion it has less influence on a thermometer. The temperature drops. It gets "cold".

Anyway, IMO you have things confused. A gas liquefier using an expansion engine or turbine to make a gas do work to remove heat to lower the temperature of the gas is not the same thing as a heat pump.

There is no work coming out of a heat pump, work is used to move the heat.

There IS work coming out of an expansion engine. The heat is not moved it is converted.

Converting heat to work does not result in a temperature difference by moving or separating the heat. When heat is converted to work it generates cold so the heat "disappears", it is not moved to some new location, it's just gone. No longer exists in the form of heat.

[Tom Booth]

A refrigeration system uses a REFRIGERANT. The Air Cycle Machine is driven by air on a common shaft, the idea of the ACM is to take the heat energy out of the air by making it do work, i.e-drive the ACM, then you have very cold air,

Post by a/c train: https://www.airliners.net/forum/viewtopic.php?t=757125

[Tom Booth]

The air is expanded through an air turbine that drives a compressor or fan, thus converting heat energy into useful work.

https://www.tasecs.com.tr/ecs-solutions ... ng-systems

[Tom Booth]

it was soon recognised that the liquefaction of gases by the advantage of the Joule-Thomson effect was not an economic proposition.

Rayleigh first suggested that if the compressed gas might be made to render some external work while suffering expansion the cooling might be more intense. Since the system is in an adiabatic condition the external work would be available at the cost of internal energy which will further augment the Joule-Thomson cooling. (...)

Claude solved some interesting difficulties he met in course of liquefaction of permanent gases. A compressed gas, if allowed to do external work during adiabatic expansion brings about an intense cooling so much so that the lubricating oil in the moving parts of the piston which is moved by the gas during expansion gets solidified and the machine is jammed. This difficulty was removed by using hydrocarbons such as petroleum ether for lubricating purposes. This remains
viscous up to about — 160°c

INTRODUCTION TO PHYSICAL CHEMISTRY VOL. I

By Prof. S. N. MUKHERJEE, d.*c.

https://archive.org/stream/in.ernet.dli ... o_djvu.txt

The fact that we actually have certain gases available in liquid form that are cooled down to cryogenic temperatures by these methods of having a gas do work as it expands adiabatically "at the cost of its internal energy" I think clearly demonstrates the conversion of heat into work.

If like "fool" you want to argue that "internal energy" is not heat, well, I can't help you.

Heat transfered into a gas becomes part of the "internal energy" of the gas. Subsequently expanding and doing work converts that "internal energy" to work and the temperature of the gas drops, dramatically. Much more than mere expansion without doing work (Joule thomson). So cold the machinery driven by the expanding gas can freeze up and seize without special lubricants

In a Stirling engine a compressed gas expands and does work. The "internal energy" of the gas is converted into work.

No heat is merely moved as in a heat pump. The heat (or internal energy of the gas that is, or came from heat) is transformed into work output so the gas cools. The heat doesn't dissipate to a "sink".

If like "fool" you want to engage in semantic hair splitting and say "internal energy" is not heat, so it's not the same, well again, I can't help you. You can think whatever pleases you.

If you want to say expansion is "isothermal" not "adiabatic". Whatever. Believe whatever you like.

It seems pretty obvious though that you aren't really interested in the topic of this thread other than for the purpose of dismissing it.

There is plenty of evidence if your willing to look at it.