Computer simulation of a finite-time Carnot engine working under ecological conditions

In the context of finite-time thermodynamics some optimization criteria for heat engines have been proposed, such as the maximum power [1] or the ecological criterion [2], being the later the best compromise between high power output and low entropy production. In order to study these criteria, we present a molecular dynamics simulation of a hard-disk gas performing a finite-time cyclic process that is near to a Carnot one. While previous works analysed the maximum power regime [3], in the present work we discuss the ecological case. When the gas is in contact with an stochastic thermal wall (or heat reservoir), we show that the speeds distribution is well described by a Maxwell-Boltzmann function with an effective temperature that is lower/higher than the source/sink temperature (as in the endoreversible model). By obtaining the power output and total entropy production, the ecological efficiency of such an engine was computed via molecular simulations for the first time, showing good agreement with analytical approaches. Our results were reported in D. A. Rojas-Gamboa et al., Phys. Rev. E 98, 022130 (2018).

[1] F. L. Curzon and B. Ahlborn, Am. J. Phy. 43, 22 (1975).
[2] F. Angulo-Brown, J. App. Phys. 69, 7465 (1991).
[3] Y. Izumida and K. Okuda, Europhys. Lett. 83, 60003 (2008).