There is a great interest in understanding the optimal features  of the performance of finite-time thermal machines. Efficiency at maximum power and the coefficient of performance at maximum cooling power, are some of the useful criteria that are studied.
Universal features of these quantities are observed in many different models, such as those based on endoreversibility assumption, low-dissipation assumption, stochastic heat engines, and even quasi-static models. We discuss a model of heat engine within the framework of linear irreversible thermodynamics.
The model runs in a finite cycle time. We show that the model can be mapped to a low-dissipation model whereby the entropy generated in a heat-exchange step, is inversely proportional to the duration of the process. The optimal features of the efficiency will be discussed.