Entropy Production gives rise to Upper- and Lower-Bounds to Efficiency and COP of Cycles

TL;DR

This paper introduces new bounds on the efficiency and COP of thermodynamic cycles derived from entropy production, enabling more accurate cycle design and fluid selection beyond traditional Carnot limits.

Contribution

It develops entropy-based upper and lower bounds for cycle efficiency and COP, improving upon traditional Carnot limits for better cycle optimization.

Findings

New bounds are closer to actual cycle performance.

Bounds improve cycle design accuracy.

Enhanced fluid selection based on bounds.

Abstract

From thermodynamics point of view, in this era of aiming at energy conservation and sustainability, we need to develop more accurate ways to design thermal power, cooling and heat pump cycles. It has been the general practice in thermodynamic analysis of cycles to use the Carnot efficiency and Carnot coefficient of performance which are the highest upper bound to efficiency and COP of cycles. In the present report through the application of the second law of thermodynamics for irreversible processes, which results in the general inequality relation for the entropy production, we have introduce new upper- and lower-bounds to the efficiency of thermal power cycles and COP of cooling and heat pump cycles. The resulting upper- and lower-bounds are closer to the actual efficiency and COP of cycles. That allows us a more precise design of cycles and the choice of cycles working fluids.