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The first law of thermodynamics is quantitatively formulated via an equation relating the internal energy of a system, the heat exchanged by it, and the work done on it. A quantitative formulation of the second law of thermodynamics leads to defining a state function, the entropy.
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Optimization, Stability, and Entropy in Endoreversible Heat Engines.

Julian Gonzalez-Ayala1,2, José Miguel Mateos Roco1,2, Alejandro Medina1,2

  • 1Instituto de Física Fundamental y Matemáticas, Universidad de Salamanca, 37008 Salamanca, Spain.

Entropy (Basel, Switzerland)
|December 8, 2020
PubMed
Summary
This summary is machine-generated.

This study analyzes endoreversible heat engine stability using new dynamic equations. Findings reveal how heat transfer symmetries impact efficiency, power, and entropy generation, offering insights into optimal engine performance.

Keywords:
Pareto frontentropy behaviormaximum power regimemultiobjective optimizationstability

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Area of Science:

  • Thermodynamics
  • Non-equilibrium thermodynamics
  • Heat transfer

Background:

  • Endoreversible heat engines are crucial for energy conversion.
  • Previous studies focused on stability but lacked dynamic equation insights.
  • Understanding heat transfer dynamics is key to optimizing engine performance.

Purpose of the Study:

  • To develop an alternative dynamic equations system for endoreversible heat engines.
  • To analyze the impact of heat transfer laws on engine stability and performance.
  • To investigate the role of conductance ratio symmetries in thermodynamic behavior.

Main Methods:

  • Formulated dynamic equations using restitution forces and Taylor expansion.
  • Analyzed specific cases of Newton and phenomenological heat transfer laws.
  • Examined a Carnot-like heat engine model.

Main Results:

  • Observed three distinct behaviors based on conductance ratio (σhc) values.
  • Small σhc improved efficiency and power with decreased entropy generation.
  • Large σhc and symmetric cases showed varied performance depending on trajectory evolution.
  • Total entropy generation defines operational and relaxation time scales.

Conclusions:

  • The symmetries of the heat transfer law significantly influence endoreversible heat engine performance.
  • Optimal efficiency and power can be achieved by managing the conductance ratio.
  • Entropy generation serves as a critical parameter for characterizing engine dynamics and time scales.