Achieving Carnot efficiency in a finite-power Brownian Carnot cycle with arbitrary temperature difference

TL;DR

This paper demonstrates that a Brownian Carnot cycle can theoretically achieve Carnot efficiency at finite power for any temperature difference by minimizing relaxation times, challenging traditional trade-offs in heat engine performance.

Contribution

It introduces a specific underdamped Brownian Carnot cycle that attains Carnot efficiency at finite power without violating the fundamental trade-off, for arbitrary temperature differences.

Findings

Carnot efficiency at finite power is achievable in the vanishing relaxation time limit.

The proposed cycle's efficiency and power are confirmed through numerical simulations.

Theoretical analysis supports the compatibility of Carnot efficiency and finite power in the model.

Abstract

Achieving the Carnot efficiency at finite power is a challenging problem in heat engines due to the trade-off relation between efficiency and power that holds for general heat engines. It is pointed out that the Carnot efficiency at finite power may be achievable in the vanishing limit of the relaxation times of a system without breaking the trade-off relation. However, any explicit model of heat engines that realizes this scenario for arbitrary temperature difference has not been proposed. Here, we investigate an underdamped Brownian Carnot cycle where the finite-time adiabatic processes connecting the isothermal processes are tactically adopted. We show that in the vanishing limit of the relaxation times in the above cycle, the compatibility of the Carnot efficiency and finite power is achievable for arbitrary temperature difference. This is theoretically explained based on the trade-off relation derived for our cycle, which is also confirmed by numerical simulations.