Entropy: Thermodynamics – Energy – Environment – Economy

Entropie - ISSN 2634-1476 - © ISTE Ltd

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In this article, after reminding the present definition of the term « heat », its evolution is summarized with focusing on the mode of heat conduction. The notion of heat has been discussed from antiquity either in East or West. First based on a sensation of hot or cold, the notion of heat for a long time has been confused with that of temperature. Two types of theories have been simultaneously developed, substantialist theories and mechanistic theories. The progression of these two types of theories has been reported from antiquity to present times. At the beginning was the Aristotelian categorization, then the phlogiston theory and, after the theories of caloric and ether for which heat is a substance but, it is shown that as soon as antic times the motion of matter corpuscles also has been associated to heat. Nevertheless, many researchers at the end of the 18th century and the beginning of 19th did not want to take sides, as did Fourier, who has formalized heat conduction in his pioneering work and who is the reference. The corpuscular interpretation is by now accepted and has followed the physics evolution especially with the quantum mechanics. So, heat conduction is associated with particle interactions and with atomic vibrations in solids. In this context, the use of the phonon quasi-particle has contributed to a large part to the present developments.

In the research on the origin of life, topics that can be considered reasonably shared by the generality of researchers are initially identified. The application of these principles to the results obtained with the mathematical model for the simulation of aggregative processes developed by the authors (and the subject of previous publications) leads to the conclusion that the primordial formation of self-replicating structures is difficult to reconcile with deterministic aggregative dynamics in the classical sense. Regardless of the extent to which the process is governed by chance or by aggregative codes written in the laws of chemistry, no conventional causality is likely. Indeed, when the model is applied to the simulation of aggregative processes in the absence of guiding elements (that is code-carrying agents, also capable to promote catalytic effects) as is likely to have been the case in the prebiotic world, the repetitive and ordered formation of sufficiently complex structures implies an entropy deficit that is difficult to justify in a classical context. Only one way out seems possible: the existence of information sets that affect the evolution of the system according to modalities other than those that depend on the flow of perceived time. The possibilities offered by quantum mechanics and its most recent interpretations are con-sequently investigated to try to shed some light, at the level of particle physics, on this enigmatic and unconventional con-jecture.

Whether it pertains the possibility of staying within old paradigms or, conversely, exploring new areas of thought that lead to genuine conceptual breakthroughs, society demands creativity (invention, innovation). The pressure exerted on designers is not only a comforting continuity but also stems from major trends related to climate change, resource depletion, inter-individual local and international relationships, and more. While this approach is often personal to a large extend, having a (good) idea without exchanging with various partners generally does not lead very far. It is essential to consider, in a more global, interdisciplinary and forward-thinking manner, how to translate and further develop the seed of an idea to bring forth realistic solutions on scientific and/or technical levels. For intelligence to be collective or collaborative, it must be effectively shared. This sharing, within heuristic processes, raises awareness of the variety and complexity of ideas and encourages acceptance of the heterogeneity of each thought, solution, practice, and behavior. The aim of this collective work is to define a critical path through which the organization will create value.

The much-needed energy transition brings special focus on fuel cell micro-combined Heat and Power (mCHP or micro-CHP) systems for residential uses, one of which is a Solid Oxide Fuel Cell (SOFC), fed by natural gas, designed to provide continuously 1.5 kWel with an associated amazingly high expected Low heating Value (LHV) electrical efficiency of 60%. This power output can be modulated as desired down to 500 Wel and heat can also be recovered to partially contribute to the heat demand of the household. This system has been installed in a laboratory environment and has been specifically instrumented in order to evaluate its performance with different thermal loads and electrical output power settings. In this paper, focus is brought on the resulting thermal output and efficiencies, both thermal and electrical, which have also been modelled with great goodness of fit. With several electrical power outputs between the 500-1500 Wel range, this study shows total High Heating Value (HHV) total efficiencies up to 88-89% at minimal return temperatures (around 20°C) in the heat recovery circuit. Maximum LHV electrical efficiency has been found to be equal to 57% at nominal output power (regardless of the thermal loads), which is close to the manufacturer’s target of 60%.

This article is dedicated to the analysis of the magnetic induction effects on the iron loss and the equivalent diagrams elements of a ferromagnetic domain subjected to this induction by using a parallelepipedic ferromagnetic domain subjected to a uniaxial magnetic flux. Induction B produced by an interdependent known source with the domain causes the domain saturation. This domain increases its consumption and sees the decrease of the resistances and the reactances values of its equivalent diagrams vis-a-vis the induction producing source. The increase in the iron loss and the reduction in the passive elements values of the equivalent diagrams are confirmed by the reduction in the resistivity and the permeability of the domain in Voltage Model where elements RL are in parallel as in Current Model where elements RL are in series. This phenomenon is visible during the duality parallel-series checking of the domain equivalent diagrams vis-a-vis the inductive source.

Bioeconomics is a new approach to the relationship between the economy and the environment developed by N. Georgescu-Roegen (1906-1994), a great economist of the 20th century who was also a mathematician, philosopher and historian of science. The economy, as a sub-system of the biosphere, is understood in a global ecological context. It is also inseparable from the historical dimension of the development of societies, given the limited access to a stock of resources (energy and matter) taken from the environment. The ultimate aim of this original approach is to reconcile economic development with ecological constraints and to lead the economy towards sufficiency.

The so-called “water vapor pump” cycle is defined by the selective recycling of the water vapor carried by the combustion products at the outlet of the thermal machine by exchange of mass and heat between the exiting combustion products and the incoming atmospheric air. With hydrogen fuel, this form of wet combustion is capable of very high energy and ecological performance. In this context, we present here the Hydrometric Combustion Diagram (HCD) of hydrogen and apply this tool to anticipate the energy performance of this new fuel whose PCS exceeds its PCI by 18%. These expectations also concern the case of gas turbines in the case of wet combustion which, moreover, are, a priori, highly consuming additional water. The formation of atmospheric water plumes, the "cost" of its elimination, the possible residual pollution due to NOx are also presented, this concerning the use of hydrogen fuel in all thermal combustion machines, including in fuel cells. All applications combined and in a cogeneration context, wet combustion, of which the so-called “water vapor pump” cycle is part, increases the dew point temperature of the combustion products by approximately 10°C and promotes useful energy recovery. approaching 100% of the higher calorific value of the fuel (100% of the PCS). What is to be emphasized with hydrogen fuel.