scholarly journals Carnot-Like Heat Engines Versus Low-Dissipation Models

Entropy ◽  
2017 ◽  
Vol 19 (4) ◽  
pp. 182 ◽  
Author(s):  
Julian Gonzalez-Ayala ◽  
José Roco ◽  
Alejandro Medina ◽  
Antonio Calvo Hernández
Keyword(s):  
Heat Engines ◽  
Low Dissipation

scholarly journals Optimization and Stability of Heat Engines: The Role of Entropy Evolution

Entropy ◽  
2018 ◽  
Vol 20 (11) ◽  
pp. 865 ◽  
Author(s):  
Julian Gonzalez-Ayala ◽  
Moises Santillán ◽  
Maria Santos ◽  
Antonio Calvo Hernández ◽  
José Mateos Roco
Keyword(s):  
Local Stability ◽  
Production Efficiency ◽  
Basin Of Attraction ◽  
Heat Engine ◽  
Time Constraints ◽  
Thermal Gradients ◽  
Heat Engines ◽  
Low Dissipation ◽  
The Basin Of Attraction

Local stability of maximum power and maximum compromise (Omega) operation regimes dynamic evolution for a low-dissipation heat engine is analyzed. The thermodynamic behavior of trajectories to the stationary state, after perturbing the operation regime, display a trade-off between stability, entropy production, efficiency and power output. This allows considering stability and optimization as connected pieces of a single phenomenon. Trajectories inside the basin of attraction display the smallest entropy drops. Additionally, it was found that time constraints, related with irreversible and endoreversible behaviors, influence the thermodynamic evolution of relaxation trajectories. The behavior of the evolution in terms of the symmetries of the model and the applied thermal gradients was analyzed.

scholarly journals Energetic Self-Optimization Induced by Stability in Low-Dissipation Heat Engines

2020 ◽  
Vol 124 (5) ◽  
Author(s):  
J. Gonzalez-Ayala ◽  
J. Guo ◽  
A. Medina ◽  
J. M. M. Roco ◽  
A. Calvo Hernández
Keyword(s):  
Heat Engines ◽  
Low Dissipation

Nonlinear Dissipation Heat Devices in Finite-Time Thermodynamics: An Analysis of the Trade-Off Optimization

2017 ◽  
Vol 42 (3) ◽  
Author(s):  
Can-can Lu ◽  
Long Bai
Keyword(s):  
Input Power ◽  
Coefficient Of Performance ◽  
Efficiency Coefficient ◽  
Nonlinear Dissipation ◽  
Characteristic Parameters ◽  
Trade Off ◽  
Heat Engines ◽  
Low Dissipation ◽  
Order Case ◽  
Quadratic Order

Abstract:The nonlinear dissipation heat devices are proposed by means of generalizing the low-dissipation heat devices to the quadratic order case. The dimensionless formulas of the output (input) power and the efficiency (coefficient of performance) for the nonlinear dissipation heat engines (refrigerators) are derived in terms of characteristic parameters for heat devices and the dimensional analysis. Based on the trade-off criterion, the optimal performance of the nonlinear dissipation heat devices is discussed in depth, and some system-specific properties for the nonlinear dissipation heat devices under the trade-off optimization are also uncovered. Our results may provide practical insight for designing actual heat engines and refrigerators.

scholarly journals Optimization and Efficiency Studies of Heat Engines: A Review

2020 ◽  
Vol 07 (03) ◽  
pp. 37-58
Author(s):  
Preety Aneja ◽  
Keyword(s):  
Objective Function ◽  
Power Efficiency ◽  
Heat Engine ◽  
Maximum Power ◽  
Maximum Efficiency ◽  
Heat Engines ◽  
Low Dissipation ◽  
Optimization Efficiency ◽  
Efficient Power ◽  
Operating Regimes

This review aims to study the various theoretical and numerical investigations in the optimization of heat engines. The main focus is to discuss the procedures to derive the efficiency of heat engines under different operating regimes (or optimization criteria) for different models of heat engines such as endreversible models, stochastic models, low-dissipation models, quantum models etc. Both maximum power and maximum efficiency operational regimes are desirable but not economical, so to meet the thermo-ecological considerations, some other compromise-based criteria have been proposed such as Ω criterion (ecological criterion) and efficient power criterion. Thus, heat engines can be optimized to work at an efficiency which may not be the maximum (Carnot) efficiency. The optimization efficiency obtained under each criterion shows a striking universal behaviour in the near-equilibrium regime. We also discussed a multi-parameter combined objective function of heat engines. The optimization efficiency derived from the multi-parameter combined objective function includes a variety of optimization efficiencies, such as the efficiency at the maximum power, efficiency at the maximum efficiency-power state, efficiency at the maximum criterion, and Carnot efficiency. Thus, a comparison of optimization of heat engines under different criteria enables to choose the suitable one for the best performance of heat engine under different conditions.

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