The entropy approach to the evolution of open systems is analyzed, using Lotka’s principle as a starting point. A Lagrangian is sought after to develop an analytical method for the evaluation of the stationary states of open irreversible systems. The stationary conditions for open systems are...

We are pleased to announce the <i>Energies</i> Best Papers awards for 2015. <i>Energies</i> is an open access journal of energy-related scientific research, technology development, and policy and management studies. It publishes reviews, regular research articles, and communications in a number of fields...

It is well known that, for a given compressor technology, gas turbine efficiency increases with the turbine inlet temperature (TIT): both modern aeronautical and land-based gas turbines operate at very high temperatures (1500–2000K) –and correspondingly high pressure ratios. As the TIT...

The paper argues against the claim made by Emergy Analysts that emergy is an exergy-based procedure. Both Emergy- and Exergy Analysis employ space- and time integrated energy input/output models to quantitatively assess the resource consumption of physical systems: the issue at stake is whether...

A novel systematic approach to the evaluation of energy conversion processes and systems, based on an extended representation of their exergy flow diagram is presented and discussed in this article. The method constitutes a substantial generalisation of Szargut’s cumulative exergy consumption...

The paper discusses the similarities and the incompatibilities between two forms of Energy Analysis (exergy and emergy, ‘EXA’ and ‘EMA’ in the following), both of which try to represent the behavior of physical systems by means of cumulative energy input/output methods that result in a...

The paper describes an application of a computational tool developed for the extended exergy accounting (EEA) of complex systems. The application is presented in an interactive graphic form to enhance its impact on the user. The computational part is based on a modular process simulator,...

This paper presents a critical and analytical description of an ongoing research program aimed at the implementation of an expert system capable of monitoring, through an Intelligent Health Control procedure, the instantaneous performance of a cogeneration plant. An application has been tested...

The long-term qualitative behavior of most real ecological populations can be mathematically classified as either asymptotic equilibrium or periodic. The reasons underlying these behaviors have been, and are still, debated. Aim of this paper is to show that it is possible to characterize both of...