The Saturated and Supercritical Stirling Cycle Thermodynamic Heat Engine Cycle

TL;DR

This paper demonstrates a theoretical thermodynamic cycle using validated data, showing that real fluids can surpass Carnot efficiency by leveraging temperature-dependent intermolecular forces as an entropic force.

Contribution

It introduces a cycle that produces negative entropy generation and provides empirical equations for internal energy changes in real fluids, challenging traditional efficiency limits.

Findings

Cycle can produce net-negative entropy generation.

Real-fluid efficiency can exceed Carnot limit.

Empirical equations for internal energy changes derived.

Abstract

On the assumption that experimentally validated tabulated thermodynamic properties of saturated fluids published by the National Institute of Standards and Technology are accurate, a theoretical thermodynamic cycle can be demonstrated that produces a net-negative entropy generation to the universe. The experimental data on the internal energy can also be used to obtain a simple, empirical equation for the change in internal energy of a real fluid undergoing isothermal expansion and compression. This demonstration provides experimental evidence to the theory that temperature-dependent intermolecular attractive forces can be an entropic force that can enhance the thermodynamic efficiency of a real-fluid macroscopic heat engine to exceed that of the Carnot efficiency.