Heat accumulation function and optimization of heat engines

Abstract

The second law of thermodynamics is presented in terms of the heat accumulation function. The meaning of the heat accumulation functions is illustrated by a practical example. The optimization problem of heat engines is formulated with the aid of the heat accumulation function at a very general level. As an example, we have studied a heat engine process where the heat input and output changes are limited by the finite heat capacity of the combustion air. We have obtained formulas for estimating the maximum efficiency for heat engines as a function of the ratio of the combustion heat and the heat capacity of the combustion air. Representative numerical examples are presented.

Dual structure of thermodynamics

“…[1] p. 101), it is easy to show that while heat conduction always increases the entropy, it always decreases F U when approaching equilibrium at T . We conclude by discussing the link of the present analysis with Serrin's theory [3,4,33], which provides an alternative formulation of thermodynamics based on hotness (i.e., temperature) and heat flow, without assuming internal energy and entropy as primitive concepts (similar concepts were developed by Silhavy [5,6]; see also [7]). The theory is formulated using an accumulation function, A(T ), defined for cyclic processes as the total heat added in a process at temperature lower or equal than T ,…”