Optimal finite-time Brownian Carnot engine

TL;DR

This paper uses thermodynamic geometry to design and analyze optimal finite-time Brownian Carnot engines, achieving significant improvements in efficiency and power over previous experimental protocols.

Contribution

It introduces a method to optimize mesoscale heat engines, deriving new cycle protocols with enhanced efficiency and reduced dissipation compared to prior experimental approaches.

Findings

20% reduction in dissipated energy compared to previous protocols

Approximately 50% improvement in efficiency under certain conditions

Engine designs outperform existing experimental Carnot cycles

Abstract

Recent advances in experimental control of colloidal systems have spurred a revolution in the production of mesoscale thermodynamic devices. Functional "textbook" engines, such as the Stirling and Carnot cycles, have been produced in colloidal systems where they operate far from equilibrium. Simultaneously, significant theoretical advances have been made in the design and analysis of such devices. Here, we use methods from thermodynamic geometry to characterize the optimal finite-time, nonequilibrium cyclic operation of the parametric harmonic oscillator contact with a time-varying heat bath, with particular focus on the Brownian Carnot cycle. We derive the optimally parametrized Carnot cycle, along with two other new cycles and compare their dissipated energy, efficiency, and steady-state power production against each other and a previously tested experimental protocol for the Carnot cycle. We demonstrate a 20\% improvement in dissipated energy over previous experimentally tested protocols and a $\sim$50\% improvement under other conditions for one of our engines, while our final engine is more efficient and powerful than the others we considered. Our results provide the means for experimentally realizing optimal mesoscale heat engines.