Performance optimization of low-dissipation thermal machines revisited

Area of Science:

• Thermodynamics
• Statistical Mechanics
• Applied Physics

Background:

• Finite-time thermodynamics analyzes heat engines operating under realistic, time-constrained conditions.
• The low-dissipation assumption simplifies analysis by minimizing irreversibilities during heat transfer.
• Traditional optimization methods for Carnot machines can yield complex equations.

Purpose of the Study:

• To develop a simplified optimization scheme for finite-time Carnot machines.
• To derive closed-form expressions for performance metrics.
• To apply the scheme to various objective functions for engines and refrigerators.

Main Methods:

• Revisiting the optimization of finite-time Carnot machines under low-dissipation.
• Proposing an alternate optimization scheme: first optimizing work for a given cycle time, then optimizing another function over cycle time.
• Solving the optimization problem with simplified calculations.

Main Results:

• The proposed scheme simplifies the optimization process significantly.
• Closed-form expressions for figures of merit are obtained.
• The approach is demonstrated effectively for both engines and refrigerators.

Conclusions:

• The new optimization approach offers a more tractable method for analyzing finite-time thermodynamic cycles.
• This simplification facilitates a deeper understanding and improved design of heat engines and refrigerators.
• The findings are broadly applicable to various performance objectives in thermodynamics.