scholarly journals The Way of Entropy: from Lagrangian Modelling to Thermal Engineering

Author(s):  
Nilo Serpa ◽  
Gisele Alves Fernandes

<p>This article discusses the concept of entropy in an alternative thermodynamic view, demonstrating dialectically that the reversibility illustrated in common laboratory practice is only a local technical effect resulting from anthropic processes that slow down the irreversible advance of the disorder. Then, negative entropy is only a fiction stemming from the imaginationist idealism. The Lagrangian formalism is applied from the introduction of the idea of temporal confinement of thermal energy states, with time being interpreted as the basis of an evolutionary variable. The acceleration of entropy is formally presented independently of statistical mechanics.</p><p><br /><strong>Key words</strong>: thermodynamics, entropy, entropy acceleration, irreversibility.</p><p>=================================================================</p><p>O presente artigo discute o conceito de entropia numa visão termodinâmica alternativa, demonstrando dialeticamente que a reversibilidade ilustrada na prática laboratorial comum é apenas um efeito técnico local decorrente de processos antrópicos que desaceleram o avanço irreversível da desordem. Dessa forma, entropia negativa é uma ficção decorrente do idealismo imaginacionista. O formalismo Lagrangeano é aplicado a partir da introdução da ideia de confinamento temporal dos estados de energia térmica, com o tempo sendo interpretado como base de uma variável evolutiva. A aceleração da entropia é formalmente apresentada de modo independente da mecânica estatística.</p><p><br /><strong>Palavras-chave</strong>: termodinâmica, entropia, aceleração da entropia, irreversibilidade.</p>

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1988 ◽  
Author(s):  
Qimei Chen ◽  
Yan Wang ◽  
Jianhan Zhang ◽  
Zhifeng Wang

Decreasing the levelized cost of renewable energy and improving the stability of power systems are the key requirements for realizing the sustainable growth of power production capacity. Concentrating solar power (CSP) technology with thermal energy storage can overcome the intermittent and unstable nature of solar energy, and its development is of great significance for the sustainable development of human society. In this paper, topic discovery and clustering were studied using bibliometric, social network analysis and information visualization technology based on the Web of Science database (SCI-Expanded) and the incoPat global patent database. The technology searched for papers and patents related to CSP technology to reveal the development trends of CSP technology and provide the references for related technical layout and hot spot tracking. The results show that the global output of CSP technology papers has continued to grow steadily, whereas the number of patent applications showed a significant downtrend. CSP technology, which is at the initial stage of commercialization, still needs technological breakthroughs. Technological innovation that integrates thermal engineering, control engineering, physics, chemistry, materials, and other disciplines may become an effective path for CSP technology development in the future. CSP technology research shows increasing research and development trends in high-temperature receivers, phase-change thermal energy storage, the overall performance of thermal power generation systems, and a development trend from a single technology to multi-energy complementary systems.


2014 ◽  
Vol 20 (1) ◽  
pp. 77-93 ◽  
Author(s):  
Heiko Hamann ◽  
Thomas Schmickl ◽  
Karl Crailsheim

A grand challenge in the field of artificial life is to find a general theory of emergent self-organizing systems. In swarm systems most of the observed complexity is based on motion of simple entities. Similarly, statistical mechanics focuses on collective properties induced by the motion of many interacting particles. In this article we apply methods from statistical mechanics to swarm systems. We try to explain the emergent behavior of a simulated swarm by applying methods based on the fluctuation theorem. Empirical results indicate that swarms are able to produce negative entropy within an isolated subsystem due to frozen accidents. Individuals of a swarm are able to locally detect fluctuations of the global entropy measure and store them, if they are negative entropy productions. By accumulating these stored fluctuations over time the swarm as a whole is producing negative entropy and the system ends up in an ordered state. We claim that this indicates the existence of an inverted fluctuation theorem for emergent self-organizing dissipative systems. This approach bears the potential of general applicability.


2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Hermes Chirino ◽  
Ben Xu

Compared to solar photovoltaics, concentrated solar power (CSP) can store excessive solar thermal energy, extend the power generation, and levelize the mismatch between the demand and supply. Thermal energy storage (TES) system filled with phase change material (PCM) is a key to make CSP competitive, and it is also a promising indirect energy storage technique. It is of great interests to the solar thermal engineering community to apply the latent heat thermal energy storage (LHTES) system for large-scale CSP application, because PCMs can store more energy due to the latent heat during the melting/freezing process. Therefore, a comprehensive parametric analysis of LHTES system is necessary in order to identify the most sensitive ranges of various parameters to design the LHTES system with better systematic performances. In this study, unlike the existing parametric study based on dimensional parameters, we aimed to provide a more general analysis using dimensionless parameters; therefore, an 11-dimensionless-parameter space of LHTES system was developed, by considering the technical constraints (material properties and operation parameters), without economic constraints. The parametric study and sensitivity analysis were then performed based on a 1D enthalpy-based transient model, and the energy storage efficiency was used as the objective function to minimize the number of variables in the parameter space. It was found that Stanton number (St), dimensionless PCM radius (r/D), and void fraction (ε) are the three most important dimensionless parameters. It is expected that the discovery of this study can bring more discussions in the solar thermal engineering community about the implementation of LHTES system in CSP plant, to further explore the significances of these three dimensionless parameters to the operation of the LHTES system.


1997 ◽  
Vol 77 (3) ◽  
pp. 369-374 ◽  
Author(s):  
K. S. Schwartzkopf-Genswein ◽  
J. M. Stookey ◽  
A. M. de Passillé ◽  
J. Rushen

Thirty yearling (450–500 kg) heifers of mixed breeds (Hereford, Charolais, Angus and Shorthorn) were habituated to handling over a 14 ± 2 d period before branding and were fitted non-surgically with jugular catheters 1 before branding. On the day of branding, heifers were assigned to hot-iron brand (H), freeze brand (F), or control (C) treatments according to a predetermined randomized branding order (n = 10 per treatment). Blood samples were obtained at 20 and 0 min before and 20, 40, 60, 80, 100, 120, 140, 160 and 180 min after application of branding treatments. To detect stress-induced analgesia, each animal's sensitivity to pain was assessed by measuring the time it took them to respond to a thermal energy source (laser) applied to their hind legs. Foot-lift latencies were obtained 0, 10, 20, 60 and 120 min after the treatments were imposed. Sensitivity to touch also was assessed 1 and 7 d after branding by placing pressure on the brand site and measuring the amount of movement by the animals. Both H and F heifers had higher mean plasma cortisol concentrations than C animals 20 and 40 min after branding (P < 0.05). However, hot branding was found to cause a more pronounced cortisol response than freeze branding at 40 min (P < 0.05). No treatment differences in foot-lift latencies or sensitivity to touch were observed. Both branding methods cause discomfort in cattle; however, hot branding appears to cause a greater acute response than freeze branding. Key words: Branding, cattle, cortisol, stress-induced analgesia


2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Siavash H. Sohrab

A scale-invariant model of statistical mechanics is applied to describe modified forms of zeroth, first, second, and third laws of classical thermodynamics. Following Helmholtz, the total thermal energy of the thermodynamic system is decomposed into free heat U and latent heat pV suggesting the modified form of the first law of thermodynamics Q = H = U + pV. Following Boltzmann, entropy of ideal gas is expressed in terms of the number of Heisenberg–Kramers virtual oscillators as S = 4 Nk. Through introduction of stochastic definition of Planck and Boltzmann constants, Kelvin absolute temperature scale T (degree K) is identified as a length scale T (m) that is related to de Broglie wavelength of particle thermal oscillations. It is argued that rather than relating to the surface area of its horizon suggested by Bekenstein (1973, “Black Holes and Entropy,” Phys. Rev. D, 7(8), pp. 2333–2346), entropy of black hole should be related to its total thermal energy, namely, its enthalpy leading to S = 4Nk in exact agreement with the prediction of Major and Setter (2001, “Gravitational Statistical Mechanics: A Model,” Classical Quantum Gravity, 18, pp. 5125–5142).


2021 ◽  
Vol 14 (8) ◽  
Author(s):  
Carlos Cuviella-Suárez ◽  
Antonio Colmenar-Santos ◽  
David Diez-Borge

Abstract Ceramic industry manufacturing requires a great amount of thermal energy. Its sustainability and environmental impact demand an effort to develop more efficient technologies to reduce the consumption of fuel, mainly natural gas. In particular, the sanitary-ware production sector presents a defined special map of consumption through the manufacturing process because of the heat amounts and thermal levels of temperature. The aim of this research is to quantify the potential reduction of fuel consumption within a standard factory of sanitary-ware articles. The scope of it covers the main gas consumers, namely, kilns, dryers, heating units, or boilers. The method is based in a simulation of the process by modeling the thermophysics of the consumers, then plotting the heat recovery from one to another in order to save natural gas input. The research shows how the thermal requirement would be cut by almost a half within the factory consumption. It is consequently concluded that efficiency, environmental impact, and sustainability of this industrial sector would be improved, so as the global economy related with a potential growth of this industry, mainly in developing countries. Graphical abstract Highlights Thermal consumption reduction in a sanitary-ware factory is presented and validated. Heat recovery from kilns provides thermal energy for the rest of the thermal consumers. Energy management accounting as an extension to environmental management accounting is provided. The proposed method produces reductions of resources and economic improvements.


2021 ◽  
Vol 14 (8) ◽  
Author(s):  
Carlos Cuviella‑Suárez ◽  
Antonio Colmenar‑Santos ◽  
David Borge‑Diez

Sign in / Sign up

Export Citation Format

Share Document