High School Stirling efficiency and practice

[Pisica]

https://www.physicsforums.com/threa...-is-it-the-same-as-the-carnot-engine.1066209/

Not to disturb these discussions, I think we should open the discussion about Stirling efficiency and practice.

The majority say that the Stirling efficiency is ideally the Carnot efficiency. That is, it would depend only on Th and Tc through eff=1-Tc/Th

From this formula we deduce that the efficiency increases with the Th-Tc temperature difference and with the compression ratio V2/V1

 

[Pisica]

And then, if so, why does this man uses a pump at Stirling generator? That it does not change either the compression ratio or the temperature difference?

 

[kazaly]

Quite simply more atoms per unit volume of the working fluid thus delivering greater heat carrying capacity. This leads to an increase in system power.

 

[Pisica]

Quite simply more atoms per unit volume of the working fluid thus delivering greater heat carrying capacity. This leads to an increase in system power.

Are you saying that a higher internal air pressure leads to a higher mechanical work obtained, but without changing the efficiency of the engine?
That is, higher pressure of the working gas, leads to a higher mechanical work obtained but with proportionally higher heat consumption?

 

[Pisica]

Let's make a comparison: the Otto or Diesel engine with or without the turbine.
The turbo engine has more power at the same compression ratio, but also consumes proportionally more fuel.
Practically, the efficiency does not increase.

The Diesel engine can have a higher compression ratio than the Otto engine, so the Diesel engine has a higher efficiency,
This verifies the formula that the efficiency depends on the compression ratio.

I want to say that the man who uses the pump to increase the amount of air in the cylinder of the Stirling generator does the same thing as the turbine for the Otto engine and still does not increase its efficiency.