Universal trade-off relation between power and efficiency for heat engines

TL;DR

This paper establishes a universal lower bound on dissipation in thermodynamic systems, proving that heat engines with nonzero power cannot reach Carnot efficiency, applicable to far-from-equilibrium systems without symmetry assumptions.

Contribution

It introduces a universal trade-off relation between power and efficiency, rigorously proving the impossibility of achieving Carnot efficiency at finite power in general thermodynamic systems.

Findings

Nonvanishing heat current implies unavoidable dissipation.

Heat engines with finite power cannot reach Carnot efficiency.

The theory applies broadly to systems far from equilibrium without symmetry constraints.

Abstract

For a general thermodynamic system described as a Markov process, we prove a general lower bound for dissipation in terms of the square of the heat current, thus establishing that nonvanishing current inevitably implies dissipation. This leads to a universal trade-off relation between efficiency and power, with which we rigorously prove that a heat engine with nonvanishing power never attains the Carnot efficiency. Our theory applies to systems arbitrarily far from equilibrium, and does not assume any specific symmetry of the model.