Stirlingengineforum.com

Why?

Fool wrote: ↑Sat Aug 17, 2024 11:15 amWhy?

By your calculous, all heat engines have an efficiency of zero, since all energy resolves back into heat sooner or later.

Pointless nonsense.

I guess we'll just have roll the definition back to either effective work, or thermodynamic work. Depending, of course, what you are analyzing at the time, or interested in. Effective work is the one that comes out of a dynamometer.

Tom Booth wrote: ↑Sat Aug 17, 2024 7:35 am
My intention was simply to build a Stirling engine to run on my wood stove. Something with useable power output, which seemed to suggest that improvements in Stirling engine design would be needed.

I've seen that reason mentioned by many guys on this path. It's my own reason for being here as well. And I got sucked into the whole discussion.

Just out of curiosity, did you ever finish that engine for your stove?

Fool wrote: ↑Sat Aug 17, 2024 1:07 pm I guess we'll just have roll the definition back to either effective work, or thermodynamic work. Depending, of course, what you are analyzing at the time, or interested in. Effective work is the one that comes out of a dynamometer.

Jack can do what he likes. Personally I'm not concerned about work output at all.

I'm only concerned about, if I'm running an engine on ice, how much "waste heat" is getting to, and melting the ice.

I could care less if some heat is lost to friction or other things.

If this engine is running on ice, all the points of potential heat generation from friction simply return to the environment.

My only concern is how much heat passes through to the cold side of the engine down into the ice.
All so-called "waste heat" from friction, if it can be called that, is on the hot side of the engine and may potentially INCREASE the temperature difference, if anything.

If the heat isn't going THROUGH to the cold side it's irrelevant as far as I'm concerned.

Besides, friction can always be reduced.

If you think heat is being "rejected" by the piston displacing atmosphere, so what? The PP is on the hot side as well.

Heat rejected to the cold plate should be directly proportional to the temperature difference and the amount of effective work, and or, thermodynamic work being developed.

Without measuring an indicator diagram or work output using a dynamometer, and actual heat input, the amount of expected heat coming out of the cold plate can't be determined.

The PP will reject energy regardless of being on the hot side or cold side. You will never see the atmosphere absorb it. It comes out as work. Or as lack of work.

Developing zero thermodynamic work will have zero heat out of the cold plate. The thermodynamic work developed by the gas in those LTD Stirling Engines is probably way less than a Watt, probably 0.02 Watts or less. The indicator diagram is the best way to find it out.

One of those engines running without an external load will generate very little thermodynamic work because the engine is so small and friction so low. The thermal equivalent to flywheel spinning down. The PV diagram will show a cycle very close to the buffer pressure. Very little beat in. Very little beat out. Slowing it with an additional load, will expand the area of that cycle.
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Fool wrote: ↑Sun Aug 18, 2024 5:14 am Heat rejected to the cold plate should be directly proportional to the temperature difference and the amount of effective work, and or, thermodynamic work being developed.

Without measuring an indicator diagram or work output using a dynamometer, and actual heat input, the amount of expected heat coming out of the cold plate can't be determined.

The PP will reject energy regardless of being on the hot side or cold side. You will never see the atmosphere absorb it. It comes out as work. Or as lack of work.

Developing zero thermodynamic work will have zero heat out of the cold plate. The thermodynamic work developed by the gas in those LTD Stirling Engines is probably way less than a Watt, probably 0.02 Watts or less. The indicator diagram is the best way to find it out.

One of those engines running without an external load will generate very little thermodynamic work because the engine is so small and friction so low. The thermal equivalent to flywheel spinning down. The PV diagram will show a cycle very close to the buffer pressure. Very little beat in. Very little beat out. Slowing it with an additional load, will expand the area of that cycle.
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Heat transfered into the engine is not determined by work output.

Heat IN is a matter of the ∆T and the thickness and material the heat is transfered across.

Heat transfer into the engine is not reduced by reduced work output.

According to the Carnot theory and conservation of energy reducing work output INCREASES waste heat.

1 Joule in
0.2 joules work
0.8 joules waste heat

Less work

1 Joule in
0.0001 joules work
0.9999 joules waste heat

Less work, more "waste heat"

Without measuring an indicator diagram or work output using a dynamometer, and actual heat input, the amount of expected heat coming out of the cold plate can't be determined.

Maybe not.

But again, irrelevant for my purposes

The amount of ACTUAL "waste heat" across the cold plate and into the ice in a running engine can certainly be observed relative to a non operational engine.

The actual results of such experiments so far is that a running engine doing the bare minimum of "work" just to keep itself running and overcome friction does indeed reduce the amount of "waste heat" so that the ice melts measurably more slowly.

These results were consistent over the course of several experiments using varying quantities of ice.

So far the indication is in accordance with conservation of energy.

More work, (some work in a running engine vs. Zero work in a non running engine) produces LESS "waste heat".

If that trend continues, additional work should produce even less waste heat.

Your opinion that more work is required before seeing any waste heat is contrary to both conservation of energy as well as the experimental results.

Your objections are nothing more than an attempted debunking or invalidation of the experimental results you apparently don't like.

Less work or zero "useful" work does not translate into less waste heat. Quite the opposite

More work output means less waste heat not more. It's simple mathematics.

Of course I have no objections to such experiments being carried further, having the engine do additional "useful" work and taking additional measurements and readings

Personally I just haven't had the time or the budget for more than what I have already done.

Cheers if Jack or anyone else cares to take the experiments further

But your attempts at discrediting my experiments with your illogical arguments is not being constructive or helpful.

Tom Booth wrote:Heat transfered into the engine is not determined by work output.

If the load on an engine is removed, they tend to overheat. IMHO, that means the engine stops cooling the gas as much. It speeds up giving less time to absorb heat. So the gas in the hot side rises in temperature. That rise in temperature reduces the heat coming in.

Fool wrote: ↑Sun Aug 18, 2024 5:14 am Heat rejected to the cold plate should be directly proportional to the temperature difference and the amount of effective work, and or, thermodynamic work being developed.

...

Baloney

Waste heat or "heat rejected" is inversely proportional to the work output not "directly proportional".

You don't appear to even know or understand the theory you are advocating or conservation of energy.

And that "or" highlighted is not intended to indicate equivalence.

My theory isn't any different than yours or classical thermodynamics. It is the ability to measure what you are claiming, where we differ.

I think not very much heat, less than a Watt, is going into the gas of your little test engines.

You think they are converting 70 plus Watts into work that you can't measure.

I think a PV diagram Is the best way to research this.

I think the temperature measurements you've done are insufficient for any conclusions. You think they are definitive.

We aren't that far different. I can only imagine that you agree a PV diagram would be interesting.

I only agree that you seem to be a professional liar deliberately spreading misinformation fear and confusion in an attempt to discredit and derail legitimate research. A disgusting pig of an individual.

i don't see how encouraging you to measure a PV diagram can possibly be construed be a lie or discouragement.

Tom Booth wrote: ↑Sun Aug 18, 2024 11:49 am I only agree that you seem to be a professional liar deliberately spreading misinformation fear and confusion in an attempt to discredit and derail legitimate research.

Playing with ice cubes is not legitimate research.

Tom Booth wrote: ↑Sun Aug 18, 2024 11:49 am A disgusting pig of an individual.

more clinical projection

matt brown wrote: ↑Sun Aug 18, 2024 12:13 pm

Tom Booth wrote: ↑Sun Aug 18, 2024 11:49 am I only agree that you seem to be a professional liar deliberately spreading misinformation fear and confusion in an attempt to discredit and derail legitimate research.

Playing with ice cubes is not legitimate research.

Tom Booth wrote: ↑Sun Aug 18, 2024 11:49 am A disgusting pig of an individual.

more clinical projection

The same goes for you "Matt".

I'd give you both more credit as just plain stupid and ignorant, but the sophistication of your lies along with their deliberate and calculated nature betrays your true intentions.