Heat transfer effect on the performance of thermal Brownian heat engine

Abstract

A new finite time thermodynamic model of thermal Brownian heat engine is established. The heat transfer between heat reservoir and viscous medium is considered and is assumed to be obeyed Newton’s heat transfer law. The effects of heat transfer process on system performance are studied in detail. The key performance parameters of system are derived. For the fixed temperature of reservoirs, the temperatures of viscous medium are optimized for maximizing the power. For a fixed total heat exchanger inventory, the distribution of heat exchanger inventory is also optimized for maximizing the power. The effects of key parameters on the performance of the system are investigated, and the optimal operating region is given. The results show that the thermodynamic performance of system can be improved by enhancing the heat transfer between reservoir and heat engine. There exist optimal distribution of heat exchanger inventory and optimal temperatures of viscous medium corresponding to the maximum power, respectively. There also exists a pair of barrier height and external load corresponding to double maximum power. The efficiency decreases versus barrier height and increases versus external load. The asymmetry potential is relevant to the heat flow caused by overcoming external load of particles. The efficiency is irrelevant to the working temperature, and it only depends on the internal parameters of heat engine.