Second-law efficiency: The role of the second law of thermodynamics in assessing the efficiency of energy use

1975 ◽  
Author(s):  
null
Keyword(s):  
Energy Use ◽  
Second Law Of Thermodynamics ◽  
Second Law

A Thermodynamic Efficiency Concept for Heat Exchange Devices

1983 ◽  
Vol 105 (1) ◽  
pp. 199-203 ◽  
Author(s):  
L. C. Witte ◽  
N. Shamsundar
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Energy Use ◽  
Second Law Of Thermodynamics ◽  
Thermodynamic Efficiency ◽  
Second Law ◽  
Two Fluids ◽  
Environment Temperature ◽  
Efficiency And Effectiveness ◽  
The Mean

A thermodynamic efficiency based on the second law of thermodynamics is defined for heat exchange devices. The efficiency can be simply written in terms of the mean absolute temperatures of the two fluids exchanging heat, and the appropriate environment temperature. It is also shown that for a given ratio of hot to cold inlet temperatures, the efficiency and effectiveness for particular heat exchange configurations are related. This efficiency is compared to second-law efficiencies proposed by other authors, and is shown to be superior in its ability to predict the effect of heat exchanger parameter changes upon the efficiency of energy use. The concept is applied to typical heat exchange cases to demonstrate its usefulness and sensitivity.

The Role of Probability in Defining Entropy

2017 ◽  
pp. 152-157
Author(s):  
Alberto Gianinetti
Keyword(s):  
Second Law Of Thermodynamics ◽  
Microscopic Level ◽  
Second Law ◽  
Probability Of Occurrence ◽  
Expected Outcome

As a probabilistic law, the second law of thermodynamics needs to be conceptualized in terms of the probabilities of events occurring at the microscopic level. This determines the probability of occurrence for macroscopic phenomena. For the best comprehension of this approach, it is necessary to distinguish between “probabilities”, which are subjective predictions of an expected outcome, and “frequencies”, which are objective observations of that outcome. This distinction is of help to unravel some ambiguities in the interpretation of the second law of thermodynamics.

scholarly journals Revisiting the nature of dark sunspots: the sun as a heat engine

2021 ◽  
Vol 5 (1) ◽  
pp. 6-9
Author(s):  
Soika Alexander Kuzmich
Keyword(s):  
Solar Activity ◽  
Heat Sink ◽  
Optical Radiation ◽  
Heat Engine ◽  
Physical Nature ◽  
Second Law Of Thermodynamics ◽  
Dissipative Structures ◽  
Second Law ◽  
The Sun

This work is a continuation of the author's studies,1,2,3 related to the elucidation of the physical nature of dark sunspots. They showed that the appearance of cold sunspots, the temperature of which is below the temperature of the photosphere, is incompatible with the second law of thermodynamics. Sunspots in the Sun's photosphere can only be hot. This article provides a thermodynamic analysis of the work of the Sun as a heat engine. It is shown that sunspots are dissipative structures that spontaneously appear in the photosphere of the Sun and ensure its viability as a source of optical radiation. Sunspots play the role of a cooler for the sun's global heat engine, and without them its radiant glow would be impossible, just like the operation of any heat engine without a cold heat sink. In addition, it is shown that all the phenomena of solar activity are caused by the operation of the photospheric heat engine of the Sun, in which sunspots are the source of heat.

Modelling ‘Life’ against ‘heat death’

2017 ◽  
Vol 17 (1) ◽  
pp. 61-69
Author(s):  
Michail Zak
Keyword(s):  
Dynamical Systems ◽  
Liouville Equation ◽  
Second Law Of Thermodynamics ◽  
Quantum Systems ◽  
Living Systems ◽  
Second Law ◽  
New Class ◽  
Heat Death ◽  
The Universe

AbstractThis work is inspired by the discovery of a new class of dynamical system described by ordinary differential equations coupled with their Liouville equation. These systems called self-controlled since the role of actuators is played by the probability produced by the Liouville equation. Following the Madelung equation that belongs to this class, non-Newtonian properties such as randomness, entanglement and probability interference typical for quantum systems have been described. Special attention was paid to the capability to violate the second law of thermodynamics, which makes these systems neither Newtonian, nor quantum. It has been shown that self-controlled dynamical systems can be linked to mathematical models of living systems. The discovery of isolated dynamical systems that can decrease entropy in violation of the second law of thermodynamics, and resemblances of these systems to livings suggests that ‘Life’ can slow down the ‘heat death’ of the Universe and that can be associated with the Purpose of Life.

scholarly journals Bulk entropy is crucial to validate the second law of the extended black hole thermodynamics

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
De-Chang Dai ◽  
Djordje Minic ◽  
Dejan Stojkovic
Keyword(s):  
Black Hole ◽  
Cosmological Constant ◽  
Environmental Effects ◽  
Phase Structure ◽  
Second Law Of Thermodynamics ◽  
Black Hole Thermodynamics ◽  
Second Law ◽  
Vacuum Decay ◽  
Matter Energy

Abstract The extended black hole thermodynamics in which the cosmological constant plays the role of pressure significantly enriches the phase structure of the theory. In order to understand the extended black hole thermodynamics more precisely, we let the value of the cosmological constant vary dynamically via tunneling from one vacuum to another in a black hole induced vacuum decay. In this process, entropy of the matter/energy released by a black hole is crucial to validate the second law of thermodynamics. In other words, without taking this bulk entropy into account, entropy associated with the black hole and cosmological horizons may not always increase. Since the bulk entropy is not represented by the black hole and the cosmological horizons, this result calls for a more careful interpretation of the holographic principle in which environmental effects are taken into account.

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