Global Journal of Science Frontier Research, A: Physics and Space Science, Volume 23 Issue 1

J j =L ji X i –L jj X j . (23) In particular, as is well known from the practice of working with a welding transformer, an increase in the voltage in the secondary circuit X j (approaching the "no- load" mode) causes a decrease in the current in the primary circuit J j, and the "short circuit" mode ( X j = 0) on the contrary, increases it. Thus, Equations (22, 23) are more consistent with the phenomenological status (based on experience) than is Equation (9). It is no less important that the condition of interconnection of forces and fluxes (19) is a consequence of the law of conservation of energy (6). Under conditions of system relaxation, these conditions of counter-directional flux are absent, so that the fluxes J i and J j become independent. In this case, the reciprocity relations L ij = L ji are fulfilled trivially (they vanish), and the equations of transfer and relaxation take the form of equations of heat conduction, electrical conductivity, diffusion, etc., in which the flux J i becomes a unique (eponymous) functionof the thermodynamic force X i. This independence was also assumed in the theory of L. Onsager, since he defined the scalar fluxes J i as time derivatives of the independent parameters of the system.Therefore, strictly speaking, he did not have sufficient grounds for postulating rules (9), in which each of the fluxes depends on all forces acting in the system. VI. D evelopment of a U niversal C riterion for the E fficiency of E nergy C onverters It is generally accepted that the energy conversion efficiency of any reversible non-thermal machine is equal to unity, while for a heat engine it is limited by the thermal efficiency of an ideal Carnot machine [15]: η t = 1– T 2 / T 1 <1, (24) where T 1 , T 2 are constant temperatures of supply and removal of heat in the heat engine cycle, equal to the absolute temperatures of the heat source and sink. This “discrimination” of heat engines is based on the firm belief that “heat and work are, in principle, unequal” [15].In fact, a closer look reveals that this reflects a misunderstanding of the concepts of absolute and relative efficiency. Thermal efficiency η t , like its analog η i for ordered forms of energy, characterize the ratio of the work W i performed by the converter to the energy U i supplied from the source of the i th form of energy. Such efficiencies are usually called absolute. According to the theorem of Carnot efficiency, an ideal cycle of the heat engine does not depend on the properties of its working body, nor on the design features of the machine or the mode of operation. Therefore, such "efficiency" more likely characterizes not its coefficient of performance, but rather the possibilities offered by nature thanks to its inherent spatial in homogeneity (difference of temperatures of the hot and cold heat sources). Strictly speaking, this figure should not have been called "machine efficiency" because this figure is characterized more by the "degree of instability" of the heat source. The concept of efficiency of electric and other motors has a different meaning. Such efficiencies characterize the ratio of the work W i actually performed by the engineto the theoretically possible work W i t . They take into account the losses in the machine itself and are ideally equal to one. Such efficiencies are called relative internal η oi. In thermodynamics such efficiency η oi is an evaluation of the performance of the processes of compression or expansion of a body upon which work is done. Naturally, the application of the same term "efficiency" to these two fundamentally different concepts causes non-specialists to misunderstand the inefficiency of heat engines. In this respect, it is very useful to represent the efficiency through energy fluxes. Non equilibrium thermodynamics allows us to express the efficiency ratio in terms of the output power N j and the input transforming device N i [16]: η N =N j / N i =X j · J j / X i · J i ≤ 1. (25) This efficiency, which we term “power-based energy conversion efficiency”, or henceforth “power efficiency” for short, is equally applicable to thermal and nonthermal, cyclic and acyclic, straight and reversed machines, including the "direct energy conversion" machines. It takes into account both the kinetics of the energy conversion process and all types of losses associated with both the delivery of energy to the energy converter and the energy conversion process itself. It also depends on the operating mode of the installation, twice turning to zero: in “idle” ( J j = 0) and in “short circuit” modes ( X j = 0). This also distinguishes it from the "exergy" efficiency, which is expressed by the ratio of free energies at the outlet and inlet of the installation. In a word, this efficiency most fully reflects the thermodynamic performance of the installation and the degree to which it realizes the possibilities that the source of ordered energy provides. Moreover, such an efficiency is the only possible indicator of the performance of an installation in those cases when the concept of absolute efficiency becomes inapplicable due to the impossibility of separating energy sources and receivers in a continuous medium. Examples include force fields, chemically reactive environments, polarized or magnetized bodies, or dissociated or ionized gases. All this makes it an irreplaceable tool for analyzing the efficiency of not only energy, but also technological installations, as well as energy converters 1 Year 2023 13 © 2023 Global Journals Global Journal of Science Frontier Research Volume XXIII Issue ersion I VI ( A ) New Applications of Non-Equilibrium Thermodynamics