Stirlingengineforum.com

Your anticipated response is why I gave you your thread back, obviously.
Kindly stay away from mine.
Thank you.

Since Tom has graciously bowed out from his own thread, I'll give it back to him and take the next stage over to my own efficiency thread here:

https://www.stirlingengineforum.com/vie ... php?t=5661

I'm away for the weekend now, so it'll be next week before I get to it. Cheers all.

This is why the SE air needs to be hit with 2.6 times more input energy and ends up at 600K from 300K. It has to be heated up that much more because by the time it reaches double its original volume, it only has half the density of the atmospheric ambient air it has to be in pressure balance with. ...

The clearest way to compare Tom's online example (OE) with Stroller's example (SE) is to scale up Stroller's example to match it. OE starts with 1 cubic metre of air whereas SE starts with 100cc. OE's initial volume is 10,000 times bigger. SE requires 36.5J of energy input Q. Multiply by 10,000 = 36...

Fool wrote: ↑Tue May 21, 2024 12:32 pm I own a "puny" portable sawmill that has a 1950's 13000 D8 Cat motor, diesel, that runs a 5' circular saw blade.
I have a planer that is dated around 1900. To match it, with a growling 2 cycle Detroit diesel.

Plenty of offcuts and sawdust for Stirling engine fuel then.

Sorry, my mistake, I just went back and read what I calculated. In the more complex case of joules needed at constant volume, a reasonable engineering approximation would be to multiply the Cv value of air by the mass of air and the change in Temperature. 0.718 x 0.12g x 300 = 25.85J This is 9.65J l...

Please go back and read the conversation.
With the input of 36.5J, the temperature increases from 300K to 600K and doubles the volume from 100cc to 200cc.
The final pressure balances atmospheric, plus a negligible fraction for holding up the weight of the piston, which I didn't calculate.

So we are in agreement then? Earlier in the conversation with Vincent I showed that doubling the volume of 100cc of working fluid in a 1cm^2 area cylinder against atmosphere would require 36.5J of energy passed into the working fluid. Then I showed that lifting a 102g piston as well as pushing agai...

Yeah. We already covered the additional input energy required to perform work on a piston earlier in the conversation. In the response quoted, I was only considering the free expansion of the gas, so we can isolate one thermodynamic issue at a time. It would have been clearer if I'd specified that f...

It's the action of the expanding gas "consuming" energy that I am interested in. Is internal energy really reduced when the gas expands, other than by conduction losses to the surrounding colder surfaces of the engine. And if so, how exactly? The internal energy of the entire expanding vo...

I used to own a big old teak built Royal Navy launch, fitted with a Glennifer 4 cyl 13 litre diesel engine. It started on compressed air. While the engine was running, you could switch a valve on No. 3 cyl to recompress air into the tank. If you failed to start the engine with the air next time, you...

Let's start saying 1000 Joules just to give this some scale. I have not yet seen any data showing where or how the extra 1000 Joules are used by the gas to lift 1000 Newtons, as compared to just expanding against the atmosphere. Are we going to scale up the volume of air to 100,000cc too? This matt...

Great. Have a good evening.

If moving from the copper bar to the 5lb steel block made no noticeable difference to the compression of the gas, you can probably understand why I thought the compression caused by the 102g piston wasn't worth calculating out. But I'm interested to know what you think about my response to your 'des...

Sorry to hear that. As an engineer, you likely deal with scaling all the time. This is just a peanut size example. I was able to set 5 pounds of steel into oscillation with just a 40 degree Fahrenheit temperature difference and my 15cc epoxy displacer chamber. The only limit to this weight, even at...