Size dependence of efficiency at maximum power of heat engine

Type
Article

Authors
Izumida, Y.
Ito, N.

KAUST Grant Number
KUK-I1-005-04

Online Publication Date
2013-10-14

Print Publication Date
2013-10

Date
2013-10-14

Abstract
We perform a molecular dynamics computer simulation of a heat engine model to study how the engine size difference affects its performance. Upon tactically increasing the size of the model anisotropically, we determine that there exists an optimum size at which the model attains the maximum power for the shortest working period. This optimum size locates between the ballistic heat transport region and the diffusive heat transport one. We also study the size dependence of the efficiency at the maximum power. Interestingly, we find that the efficiency at the maximum power around the optimum size attains a value that has been proposed as a universal upper bound, and it even begins to exceed the bound as the size further increases. We explain this behavior of the efficiency at maximum power by using a linear response theory for the heat engine operating under a finite working period, which naturally extends the low-dissipation Carnot cycle model [M. Esposito, R. Kawai, K. Lindenberg, C. Van den Broeck, Phys. Rev. Lett. 105, 150603 (2010)]. The theory also shows that the efficiency at the maximum power under an extreme condition may reach the Carnot efficiency in principle.© EDP Sciences Società Italiana di Fisica Springer-Verlag 2013.

Citation
Izumida Y, Ito N (2013) Size dependence of efficiency at maximum power of heat engine. Eur Phys J B 86. Available: http://dx.doi.org/10.1140/epjb/e2013-40569-1.

Acknowledgements
The authors thank T.S. Komatsu and K. Okuda for valu-able discussions. Y.I. acknowledges the financial support froma Grant-in-Aid for JSPS Fellows (Grant No. 22-2109). Thiswork was partly supported by Award No. KUK-I1-005-04made by King Abdullah University of Science and Technology(KAUST).

Publisher
Springer Nature

Journal
The European Physical Journal B

DOI
10.1140/epjb/e2013-40569-1

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