Stirling cycle: Why neglect isochoric heat transfers?

[greypilgrim]

Hi.

To prove that the Stirling cycle has Carnot efficiency, one needs to neglect the isochoric heat transfers. Sure they have the same absolute value (but different signs), but it's still heat energy lost to the cold reservoir during the isothermic compression.

 

[DrClaude]

To prove that the Stirling cycle has Carnot efficiency, one needs to neglect the isochoric heat transfers. Sure they have the same absolute value (but different signs), but it's still heat energy lost to the cold reservoir during the isothermic compression.

I'm not sure I understand your question. During the isochoric stages, the working substance is in contact with a regenerator, not the cold reservoir. The transfer of heat to the cold reservoir is the same as in the Carnot cycle.