Stirling Engine & Heat Pump

Discussion on Stirling or "hot air" engines (all types)
Fool
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Re: Stirling Engine & Heat Pump

Post by Fool »

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The energy goes into accelerating the piston mass.

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Tom Booth
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Re: Stirling Engine & Heat Pump

Post by Tom Booth »

Fool wrote: Wed Oct 30, 2024 12:16 pm .

The energy goes into accelerating the piston mass.

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And, if present, the flywheel, the crankshaft, the generator and/or any additional load on the engine.
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Re: Stirling Engine & Heat Pump

Post by Fool »

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Yes. But just the piston, the mass of the movable is needed. No shaft power out.

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Tom Booth
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Re: Stirling Engine & Heat Pump

Post by Tom Booth »

Fool wrote: Wed Oct 30, 2024 8:49 pm .

Yes. But just the piston, the mass of the movable is needed. No shaft power out.

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"Mass of the movable"?

What the ... Are you talking about?

The gas needs to move the piston along with everything the piston is driving. The EMF from a generator etc.

Law of conservation of energy. The shaft power to run an electric generator is at the expense of the internal energy of the working fluid resulting in a drop in temperature.
Fool
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Re: Stirling Engine & Heat Pump

Post by Fool »

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Yes. But just the piston, the mass of the movable wall is needed. No shaft power out. No crank, flywheel, or connecting rod in a free piston engine.

In fact, an acoustic Stirling doesn't even have a piston. The mass of just the gas is used. It still has expansion with work. The work is used to push a mass of gas through the constriction tube.

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Tom Booth
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Re: Stirling Engine & Heat Pump

Post by Tom Booth »

Fool wrote: Thu Oct 31, 2024 9:24 am .

Yes. But just the piston, the mass of the movable wall is needed. No shaft power out. No crank, flywheel, or connecting rod in a free piston engine.

In fact, an acoustic Stirling doesn't even have a piston. The mass of just the gas is used. It still has expansion with work. The work is used to push a mass of gas through the constriction tube.

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Your a mental case.

Apparently the topic is incomprehensible to you.

Heat converted to WORK.

That includes ALL the work that results from the engines operation, not just the work the gas does expending.

This is well known.

An air cycle refrigerator will not work unless the engine does some external work, like driving a generator.
Fool
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Re: Stirling Engine & Heat Pump

Post by Fool »

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Amongst all your totally unacceptable immature vituperation, and personal attacks, you understand little.

Any cooler requires work input to produce cooling. What you are proposing is spontaneous heat transfer from cold to hot with the addition of power output.

Please draw a block diagram of your magical cooling off the cold side while heating the hot side refrigerator/engine that puts out this magical free power by driving an outside generator. This is a violation of the heat moves spontaneously from hot to cold, and conservation of energy, thermodynamic observation.

Internal thermal energy, U, in a solid, is molecular vibration. Ultimate cold is zero vibration. There is no negative vibration. Put a hot vibrating mass against a cold non vibrating mass. The cold non vibrating mass starts vibrating. Not as much as the hot vibrating mass was vibrating, because the hot mass cools, vibrates less, as momentum is used up to force the cold mass to vibrate. Hot moves into cold, both become warm. This is as important to learn as 'gasses always push, never pull'. That transfer is known mathematically as heat Q.

It isn't the outside work that causes the cooling. It is the piston being pushed by the gas while the volume is increasing and the piston is moving away from the inside gas. In other words, it is the inside-the-cylinder-work of the gas that cools it.

Likewise, it is the inside compression from the piston that heats the gas.

I'm sorry, but those are blatantly obvious from simple gathered data. Bicycle pump, fire piston, air compressor. Air tools, rattle gun. Etc...

Don't confuse it with the Joule-Thomson Effect.

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Tom Booth
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Re: Stirling Engine & Heat Pump

Post by Tom Booth »

Fool wrote: Fri Nov 01, 2024 7:20 am .

Amongst all your totally unacceptable immature vituperation, and personal attacks, you understand little.

Any cooler requires work input to produce cooling. What you are proposing is spontaneous heat transfer from cold to hot with the addition of power output.

Please draw a block diagram of your magical cooling off the cold side while heating the hot side refrigerator/engine that puts out this magical free power by driving an outside generator. This is a violation of the heat moves spontaneously from hot to cold, and conservation of energy, thermodynamic observation.

Internal thermal energy, U, in a solid, is molecular vibration. Ultimate cold is zero vibration. There is no negative vibration. Put a hot vibrating mass against a cold non vibrating mass. The cold non vibrating mass starts vibrating. Not as much as the hot vibrating mass was vibrating, because the hot mass cools, vibrates less, as momentum is used up to force the cold mass to vibrate. Hot moves into cold, both become warm. This is as important to learn as 'gasses always push, never pull'. That transfer is known mathematically as heat Q.

It isn't the outside work that causes the cooling. It is the piston being pushed by the gas while the volume is increasing and the piston is moving away from the inside gas. In other words, it is the inside-the-cylinder-work of the gas that cools it.

Likewise, it is the inside compression from the piston that heats the gas.

I'm sorry, but those are blatantly obvious from simple gathered data. Bicycle pump, fire piston, air compressor. Air tools, rattle gun. Etc...

Don't confuse it with the Joule-Thomson Effect.

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You are obviously completely ignorant of the basics of how an air-cycle refrigerator operates.
Fool wrote: Fri Nov 01, 2024 7:20 amIt isn't the outside work that causes the cooling. It is the piston being pushed by the gas while the volume is increasing and the piston is moving away from the inside gas. In other words, it is the inside-the-cylinder-work of the gas that cools it.

Likewise, it is the inside compression from the piston that heats the gas.
You continue to display yourself as an obviously confused and ignorant moron.

Yes the working fluid is inside the engine.

Do you suppose a refrigerator can operate without a motor "outside" to drive the compressor that drives the pistons that compress the gas?

The opposite is also true

The expanding gas drives the piston that drives the crankshaft that drives the generator that produces electromotive force that generates an electric current to power appliances, potentially miles away, OUTSIDE the engine.

If there is no load on the generator, the appliance is shut off, the working fluid does less work and cools down less.

Conservation of energy. Something you've shown over and over again you do not comprehend.
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Re: Stirling Engine & Heat Pump

Post by Fool »

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The engine speeds up, more windage. The engine does an equal amount of work, just comes out other ways.

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Tom Booth
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Re: Stirling Engine & Heat Pump

Post by Tom Booth »

Fool wrote: Fri Nov 01, 2024 3:32 pm .

The engine speeds up, more windage. The engine does an equal amount of work, just comes out other ways.

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We can assume speed is constant by use of a governor, in a Stirling that could regulate the flame/heat input, so there goes your "windage".

So now engage the clutch. The crankshaft starts turning a generator that powers a 1000 watt appliance. The burner flame increases the rate of heat input to compensate for the additional work load.

You think the engine is doing an "equal amount of work" as before the clutch was engaged?
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Re: Stirling Engine & Heat Pump

Post by Fool »

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It is doing an equal amount of cooling if the expansion is the same. If it starts cooling from a higher temperature, it will end at a higher temperature. The cooling will be with whatever expansion is present.

Every expansion in a Stirling Engine is with work, by definition. Receding piston.

Not every expansion is the same. Starting and ending temperatures, work is different.

It is partially responsible for why Stirling or any Engine has different effecencies at different throttle or RPM. Back work is temperature is responsible for back work too.

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Tom Booth
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Re: Stirling Engine & Heat Pump

Post by Tom Booth »

Fool wrote: Fri Nov 01, 2024 9:41 pm .

It is doing an equal amount of cooling if the expansion is the same. If it starts cooling from a higher temperature, it will end at a higher temperature. The cooling will be with whatever expansion is present.

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Nonsense.

Pressure/force x volume/distance.

More resistance from a heavier load, more pressure/force per unit of expansion.
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Re: Stirling Engine & Heat Pump

Post by Fool »

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Pressure, volume, and temperature, are all interrelated, and the equations have nothing to do with load on the axel.

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Tom Booth
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Re: Stirling Engine & Heat Pump

Post by Tom Booth »

Fool wrote: Sat Nov 02, 2024 10:08 am .

Pressure, volume, and temperature, are all interrelated, and the equations have nothing to do with load on the axel.

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In the real world it does.It requires more force to move a piston to drive an axle that turns a generator to power and electrical load than for the gas to simply expand driving what? According to you, not even a piston is necessary, just the gas expanding the same distance will be the same amount of work?

You're literally a complete idiot.
Fool
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Re: Stirling Engine & Heat Pump

Post by Fool »

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Not the same distance, nor speed. Gas is way less dense. It is just receding from the remaining gas and accelerating the leading/escaping gas. Doing work.

The force inside a cylinder is pressure times area. Pressure is P=∆TCvM. That equation doesn't have Watts,axel in it anywhere. Perhaps in your unacceptable immature language skills you could find some science terms and logic to use instead.

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