Stirlingengineforum.com

Tom, There is no such thing as a vacuum - the word is a useful concept, but in reality there is no such thing as a negative gas pressure. We would be in trouble if there were, as all of Earth's atmosphere would be sucked out into space. All of the demonstrations of a can/bottle/whatever imploding ar...

Tom Booth wrote: ↑Mon Aug 14, 2023 1:50 am no real work is done.

What is your definition of "Work" then?

Classically any movement of a physical object means that work was done.

In your spreadsheet diagram, do the purple sections indicate dead-space?

Tom, The simple point is that we all know that you cannot get power out of a machine without putting energy in. We can all discuss perpetual-motion as part of understanding the operation of a "perfect" Stirling engine, ie one with zero friction, but "free energy" is a whole 'noth...

Tom Booth wrote: ↑Tue Aug 08, 2023 1:58 am Apparently it's possible, once it's up and running, to shut off the air supply and recycle all of the exhaust back through the "reactor" in a closed loop.

Nope, nothing fishy about that...

Tom, It seems to me that a very simple experiment is possible, and hopefully useful, which is to de-couple the displacer from the piston of a suitable engine - probably by connecting a second flywheel. My question was meant to be somewhat rhetorical, and based round logical thought experiments but p...

Goofy, What is the point of the displacer? Is it needed?

Goofy - the problem is this: If for a moment, we ignore the "work done" on/by the piston, then what keeps the motor running? The simple answer is the alternating change in pressure of the working gas. What causes that change in pressure? The smaller reason is change of volume from the pist...

The "Cloud in a bottle" demo - it's not really an experiment - is largely a demonstration of the rather surprising properties of humidity and vapour saturation, not of temperature directly. The cloud forms because the loss of pressure moves the dew-point. (I've seen it done much more impre...

Tom,
The problem with treating ambient as being equivalent to zero, is 'pressure' doesn't agree with that at all - gas pressure at 300K is 75% of that at 400K (for the same volume) ...

What's the comment on the left, about "cold steam" all about?

Firstly - proving that Carnot is wrong is actually easier than proving it is correct - essentially Tom is claiming that Reindeer CAN fly, which is easy to prove (if true) - just need to see one flying, and/or show appropriate Maths. Secondly though, you I need to support part of (what I understand) ...

For the two-stroke engines, would it be possible to invert them, and effectively have a sump above the pistons?

What that diagram doesn't make clear, is what the two parts of the engine are meant to do? If they are intended to be linked to a common shaft, then I would suggest that that is a very bad idea - allegedly simply linking two IC engines to the same shaft is a very big deal, so getting the power outpu...

If I may expand slightly on an earlier comment or two - a "Stirling Heat Pump" is a fairly well-known device, though rarely needed/built by amateurs, I suspect! As noted, it needs something to drive it, which can just as easily be a "Stirling Engine" as anything else.