Storage of Energy in Constrained Non-Equilibrium Systems
1
Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, PL-01-224 Warsaw, Poland
2
Max-Planck-Institut für Intelligente Systeme, Heisenbergstr. 3, D-70569 Stuttgart, Germany
*
Author to whom correspondence should be addressed.
Entropy 2020, 22(5), 557; https://doi.org/10.3390/e22050557
Received: 24 April 2020
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Revised: 12 May 2020
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Accepted: 14 May 2020
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Published: 16 May 2020
(This article belongs to the Special Issue Evolution and Thermodynamics)
We study a quantity defined as the energy U, stored in non-equilibrium steady states (NESS) over its value in equilibrium , divided by the heat flow going out of the system. A recent study suggests that is minimized in steady states (Phys.Rev.E.99, 042118 (2019)). We evaluate this hypothesis using an ideal gas system with three methods of energy delivery: from a uniformly distributed energy source, from an external heat flow through the surface, and from an external matter flow. By introducing internal constraints into the system, we determine with and without constraints and find that is the smallest for unconstrained NESS. We find that the form of the internal energy in the studied NESS follows . In this context, we discuss natural variables for NESS, define the embedded energy (an analog of Helmholtz free energy for NESS), and provide its interpretation.
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Keywords:
non-equilibrium stationary states; energy fluxes; internal energy; ideal gas; heat transfer
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MDPI and ACS Style
Zhang, Y.; Giżyński, K.; Maciołek, A.; Hołyst, R. Storage of Energy in Constrained Non-Equilibrium Systems. Entropy 2020, 22, 557. https://doi.org/10.3390/e22050557
AMA Style
Zhang Y, Giżyński K, Maciołek A, Hołyst R. Storage of Energy in Constrained Non-Equilibrium Systems. Entropy. 2020; 22(5):557. https://doi.org/10.3390/e22050557
Chicago/Turabian StyleZhang, Yirui, Konrad Giżyński, Anna Maciołek, and Robert Hołyst. 2020. "Storage of Energy in Constrained Non-Equilibrium Systems" Entropy 22, no. 5: 557. https://doi.org/10.3390/e22050557
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