On the generalized concept of entropy for physical, extra-physical and chemical processes

The article presents some examples of entropy production in physical, extra-physical and chemical processes in order to demonstrate the possibility of generalizing this surprising parameter. In physical processes, the entropy assumes great significance for introduction to the second law of thermodynamics, and it is defined by means of a simple formulation of a Pfaff differential. Instead, in chemical processes, the entropic evaluations are described by the Gibbs thermodynamic theory. Concerning entropic analysis, the considered physical and chemical processes regard two different practical cases in thermodynamic science: the transfer of thermal energy in heat exchangers and combustion reactions. In particular, by means of entropic production, a comparison between different types of heat exchangers and the ecological goodness of some fuels in heat production, have been investigated. By using the information theory of Shannon and Weaver, the entropy notion extends its applicability domain, exploiting this concept also to different extra-physical applications. In this case, an urban planning process has been investigated, and by analyzing some decisive aspects, an ambiguous and absurd consequence such as the negation of second law validity, has been avoided.