Thermodynamics today

Bejan, Adrian

doi:10.1016/j.energy.2018.07.092

Cited by 33 publications

(22 citation statements)

References 42 publications

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“…The evolution of the design space of power plants, which is bordered from above by the second-law efficiencies of the new models that were adopted [3]. The S-shaped history of power generation in the U. S., the total distance covered annually by vehicles in the U. S., and the world population [17].…”

Section: Figurementioning

confidence: 99%

“…The generation of power from fire and other sources (natural, animal and human) happened because of designs with evident purpose: to move things against the steadfast opposition posed by the ambient. This is true about thermodynamics in all its domains of application, from animals (physiology, locomotion) to all the designs driven by the earth engine (atmosphere, hydrosphere, lithosphere, volcanos and hurricanes) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

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Purpose in Thermodynamics

Bejan

Tsatsaronis

2021

Energies

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This is a review of the concepts of purpose, direction, and objective in the discipline of thermodynamics, which is a pillar of physics, natural sciences, life science, and engineering science. Reviewed is the relentless evolution of this discipline toward accounting for evolutionary design with direction, and for establishing the concept of purpose in methodologies of modeling, analysis, teaching, and design optimization. Evolution is change after change toward flow access, with direction in time, and purpose. Evolution does not have an ‘end’. In thermodynamics, purpose is already the defining feature of methods that have emerged to guide and facilitate the generation, distribution, and use of motive power, heating, and cooling: thermodynamic optimization, exergy-based methods (i.e., exergetic, exergoeconomic, and exergoenvironmental analysis), entropy generation minimization, extended exergy, environomics, thermoecology, finite time thermodynamics, pinch analysis, animal design, geophysical flow design, and constructal law. What distinguishes these approaches are the purpose and the performance evaluation used in each method.

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Section: Figurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Purpose in Thermodynamics

Bejan

Tsatsaronis

2021

Energies

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“…At the level of the FLT, the energy transformation in heat exchangers is assessed using the heat transfer equation from the hotter working fluid h to the cooler fluid c: ln h c m Q AU T    (2) and the heat balance equation:…”

Section: Air Handling Unit As a Thermodynamic Systemmentioning

confidence: 99%

From Entropy Generation to Exergy Efficiency at Varying Reference Environment Temperature: Case Study of an Air Handling Unit

Streckienė

Martinaitis

Bielskus

2019

Preprint

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The continuous energy transformation processes in heating, ventilation and air conditioning systems of buildings are responsible for 36% of global final energy consumption. Tighter thermal insulation requirements for buildings have significantly reduced heat transfer losses. Unfortunately, this has little effect on energy demand for ventilation. On the basis of the First and the Second Law of Thermodynamics, the concepts of entropy and exergy are applied to the analysis of ventilation air handling unit (AHU) with a heat pump in this paper. This study aims to develop a consistent approach for this purpose, taking into account the variations of reference temperature and temperatures of working fluids. An analytical investigation on entropy generation and exergy analysis are used, when exergy is determined by calculating coenthalpies and evaluating exergy flows and their directions. The results show that each component of the AHU has its individual character of generated entropy, destroyed exergy and exergy efficiency variation. However, the evaporator of heat pump and fans have unabated quantities of exergy destruction. The exergy efficiency of AHU decreases from 45-55% to 12-15% when outdoor air temperature is within the range of -30°C…+10°C, respectively. This helps to determine conditions and components of improving the exergy efficiency of the AHU at variable real-world local climate conditions. The presented methodological approach could be used in the dynamic modelling software and contribute to a wider application of the Second Law of Thermodynamics in practice.

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“…有的评论还对与理论有关的关键概念进行重新命名并进行批判 [87,88] . 文献表明, 的概念是基于热电比拟得来的 [3] ; 在有关评论中, 将"热电比拟"重命名为"热功比拟", 进而指出传热过程与做功过程不可比拟, 意图以此动摇理论的物理基础 [87,88] . 显而易见, "热电比拟" 是传热学中十分经典的内容, 且与做功完全无关, 相关批评是完全站不住脚的 [89] .…”

Section: 不可能同时成立如果理论重复了熵产理论则其unclassified

Analyses of entropy generation and entransy for a Stirling cycle system based on generalized heat transfer law

Cai

2019

Sci. Sin.-Tech.

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Thermodynamics today

Cited by 33 publications

References 42 publications

Purpose in Thermodynamics

Purpose in Thermodynamics

From Entropy Generation to Exergy Efficiency at Varying Reference Environment Temperature: Case Study of an Air Handling Unit

Analyses of entropy generation and entransy for a Stirling cycle system based on generalized heat transfer law

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