Harmonically trapped Brownian stochastic Stirling heat engine optimal performance

In this work, I investigate mesoscopic heat engines that are constructed using a Brownian particle that is immersed in a fluid that serves as a thermal bath and subjected to harmonic confinement. By regulating the bath’s temperature and the harmonic trap’s stiffness, I create a Stirling-like heat engine with two isothermal and two isochoric branches. In particular, I concentrate on the irreversible, non-quasi-static scenario where the engine can produce a non-zero output power due to its finite duration. I found both analytical and numerical solutions for the best values of the system control parameters and the optimum efficiency of a stochastic Stirling heat engine using two optimization criteria. I get the two optimum efficiencies are constrained below by the Curzon-Ahlborn efficiency and above by the Carnot efficiency. Besides, I evaluate the overall optimal performance of the model by introducing an appropriate figure of merit. Based on the proposed figure of merit, the model shows that the second optimization criterion is three times better than the first optimization criterion as a function of Carnot efficiency. The findings indicate that the second optimization criterion outperforms the first one throughout the full range of Carnot efficiency.