True nature of the Curzon-Ahlborn efficiency

Area of Science:

• Thermodynamics
• Nonlinear Dynamics
• Energy Conversion

Background:

• The Curzon-Ahlborn efficiency has been considered the upper limit for thermal efficiency at maximum power.
• Its derivation from linear irreversible thermodynamics has been widely accepted.
• This has guided the field of finite-time thermodynamics.

Purpose of the Study:

• To challenge the universal applicability of the Curzon-Ahlborn efficiency.
• To re-evaluate its theoretical foundation beyond linear models.
• To derive a generalized expression for efficiency at maximum power.

Main Methods:

• Analysis of heat engine models beyond linear irreversible thermodynamics.
• Theoretical derivation of efficiency at maximum power for nonlinear systems.
• Comparison with the established Curzon-Ahlborn efficiency.

Main Results:

• The Curzon-Ahlborn efficiency is demonstrated to be a specific case, not a universal limit.
• It is properly associated with nonlinear heat engines.
• A generalized expression for maximum power efficiency is derived.

Conclusions:

• The universal character of the Curzon-Ahlborn efficiency is refuted.
• A new framework for understanding efficiency limits in nonlinear heat engines is proposed.
• This advances the study of finite-time thermodynamics for complex systems.