scholarly journals Negative entropy production rates in Drude-Sommerfeld metals

2021 ◽  
Vol 103 (1) ◽  
Author(s):  
Marcus V. S. Bonança ◽  
Pierre Nazé ◽  
Sebastian Deffner
2019 ◽  
Vol 99 (1) ◽  
Author(s):  
Philipp Strasberg ◽  
Massimiliano Esposito

Entropy ◽  
2019 ◽  
Vol 21 (11) ◽  
pp. 1117 ◽  
Author(s):  
Robin Masser ◽  
Karl Heinz Hoffmann

Endoreversible thermodynamics is a finite time thermodynamics ansatz based on the assumption that reversible or equilibrated subsystems of a system interact via reversible or irreversible energy transfers. This gives a framework where irreversibilities and thus entropy production only occur in interactions, while subsystems (engines, for instance) act as reversible. In order to give an opportunity to incorporate dissipative engines with given efficiencies into an endoreversible model, we build a new dissipative engine setup. To do this, in the first step, we introduce a more general interaction type where energy loss not only results from different intensive quantities between the connected subsystems, which has been the standard in endoreversible thermodynamics up to now, but is also caused by an actual loss of the extensive quantity that is transferred via this interaction. On the one hand, this allows the modeling of leakages and friction losses, for instance, which can be represented as leaky particle or torque transfers. On the other hand, we can use it to build an endoreversible engine setup that is suitable to model engines with given efficiencies or efficiency maps and, among other things, gives an expression for their entropy production rates. By way of example, the modeling of an AC motor and its loss fluxes and entropy production rates are shown.


Author(s):  
S. Kabelac ◽  
M. Siemer

The fuel cell, which is a highly promising candidate for high efficiency energy conversion, is not reaching expected conversion efficiencies of η > 0,5 yet. Parallel to standard explanations of loss mechanisms by means of overvoltages, a thermodynamic view of addressing irreversibilities by calculating local entropy production rates is helpful. Entropy production rates are calculated by multiplying local transport fluxes with appropriate driving forces, i.e., gradients of temperature, chemical potentials and electric potentials. These gradients have to be calculated by solving the set of constitutive balance equations. Before this tedious task is done, simplified model equations have to be used. The reversible fuel cell is the starting point of analysis. Results for a one-dimensional PEMFC are shown.


2007 ◽  
Vol 8 (5-6) ◽  
pp. 620-624 ◽  
Author(s):  
Stephen R. Williams ◽  
Denis J. Evans ◽  
Emil Mittag

2005 ◽  
Vol 1709 (3) ◽  
pp. 251-255 ◽  
Author(s):  
Robert C. Jennings ◽  
Enrico Engelmann ◽  
Flavio Garlaschi ◽  
Anna Paola Casazza ◽  
Giuseppe Zucchelli

2006 ◽  
Vol 1757 (11) ◽  
pp. 1460-1462 ◽  
Author(s):  
R.C. Jennings ◽  
A.P. Casazza ◽  
E. Belgio ◽  
F.M. Garlaschi ◽  
G. Zucchelli

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