Eur. Phys. J. B 53, 481-485 (2006)
https://doi.org/10.1140/epjb/e2006-00399-x

Performance characteristics of an irreversible thermally driven Brownian microscopic heat engine

¹ Department of Physics, Xiamen University, Xiamen, 361005, P.R. China
² Department of Chemistry, Xiamen University, Xiamen, 361005, P.R. China
³ Department of Physics, Quanzhou Normal College, Quanzhou, 362000, P.R. China

Corresponding author: ^a jcchen@xmu.edu.cn

Received: 2 July 2006
Revised: 8 October 2006
Published online: 1 November 2006

Abstract

Brownian particles moving in a spatially asymmetric but periodic potential (ratchet), with an external load force and connected to an alternating hot and cold reservoir, are modeled as a microscopic heat engine, referred to as the Brownian heat engine. The heat flow via both the potential energy and the kinetic energy of the particles are considered simultaneously. The forward and backward particle currents are determined using an Arrhenius' factor. Expressions for the power output and efficiency are derived analytically. The maximum power output and efficiency are calculated. It is expounded that the Brownian heat engine is always irreversible and its efficiency cannot approach the efficiency η_C of the Carnot heat engine even in quasistatic limit. The influence of the main parameters such as the load, the barrier height of the potential, the asymmetry of the potential and the temperature ratio of the heat reservoirs on the performance of the Brownian heat engine is discussed in detail. It is found that the Brownian heat engines may be controlled to operate in different regions through variation of some parameters.