Stirlingengineforum.com

Moving to the 5lb weight makes a tremendous systemic difference when the starting pressure rises 4psi from 4 extra pounds across one square inch of piston surface.

I'll think about your response until tonight.

I thought I had filmed the heavy steel block but I did not. It moved just the same as the copper bar.

https://youtube.com/shorts/WPtcVRK35nU? ... 3tzGUxqpzn

I'm an engineer, not a forensic nitpicker. I do practical calcs good enough to get the job done, and don't bother about negligible additional forces. That's because nothing ever lives up to its theoretical promise anyway. If you want to know how many millimetres or extra pascals the gas compressed ...

If the starting pressure at 300k and 100cc was 1atm + the added pressure of the 102g piston, it would be a basic pv=nrt calc. But if the temperature of 100cc at 300k and just 14.7psi is doubled to 600k, any additional weight will no longer allow expansion to 200cc. The only way to continue expansion...

Often times science is math that cannot be put into words.

In this case, it's words that cannot be put into math?

If I were a teacher I would ask to show your work. And I'm not trying to single you out. I would just like to know.

Energy required to expand the gas to 200cc AND lift a 1N weight by 1m = 36.5J + 1J = 37.5J

How does the 1J interact with the gas to lift 1N? It seems too simple to just add 1.

Where does the extra Joule go?

Professional bloviating. Lots of professional bloviating is what I see on here.

A turbo charged diesel engine uses an intercooler between the compressor and intake to the cylinder.

Pretty sure Tom was talking heat of compression, the very basis of diesel ignition.

That will still be 1J. The amount of energy required to lift 1Newton (102g at Earth's surface) through 1meter.

I understand, but how do we show that extra energy being applied to the gas, mathematically?

With the long tube to power piston I'd bet it would have a better chance at running from heat of hand if the top side was the hot side.

Seems like a good choice for cold bottom and ambient top side.

36.5j for free expansion to 200cc at 600k.

Now how would we calculate additional heat input for the 102g piston in your first example?

It looks like I goofed my earlier calc by a factor of 10, so it's 36.5J, not 3.65. 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...

I have since watched the video. Seems plausible. They make no claims for BTU output, just a temperature reduction. There is certainly an orifice.

I guess one would have to recreate the test to verify.

Yes. This is what Charles law tells us: "When the pressure on a sample of a dry gas is held constant, the Kelvin temperature and the volume will be in direct proportion." Hence: V1/T1 = V2/T2 The equation shows that, as absolute (Kelvin) temperature increases, the volume of the gas also i...

Stroller can answer other questions as he sees fit, but I would like to focus on the very basics for a moment. I'll chime back in after I get home today.