Thermal cycles in classical thermodynamics and nonequilibrium thermodynamics in contrast with finite time thermodynamics

Abstract

There appear to be some fundamental disagreements between those scientists and engineers who adhere to the principles of macroscopic classical thermodynamics and those who adhere to the principles of finite time thermodynamics. In many instances, the disagreements can be traced to differing assumptions concerning fundamental principles, definitions, etc., as well as differing interpretations of fundamental principles, definitions, etc. This paper is an attempt to clarify the issues by consideration, in somewhat laborious detail, of the basic definitions and their interpretations, considering the fundamental principles of classical thermodynamics and nonequilibrium thermodynamics. It appears to the author that nonequilibrium thermodynamics might offer a reconciliation of the disagreements and provide an approach acceptable to both sides. The work is purposely limited to considerations of importance in thermal cycles, mostly isothermal heat addition and rejection, and no attempt is made to treat even this broad field comprehensively. It is hoped that such discussions will lead to resolution of the disagreements, at least in part. Given the tendency of thermodynamicists to argue, in all probability, the discussions will lead to additional disagreements.