![]() Optimization tasks were carried out, also, for example of the piston trajectories of Otto, Diesel, Miller, Brayton, and Stirling cycles, as well as light driven engines. Among them are Carnot cycles in different variations, in sets of two and more, or with additional heat leaks, binary distillation processes, thermoelectric generators, and solar thermal heat engines. ![]() This simple endoreversible ansatz has proven to be a suitable tool to describe dissipative systems, and since its invention, numerous heat and other energy conversion engines have been modeled. The advantage of this method is that while irreversibilities and hence entropy production can only occur in interactions between the subsystems, the knowledge about equilibrium systems can still be applied to the subsystems. A particularly interesting and effective approach is endoreversible thermodynamics: The idea is to divide the overall system into reversibly acting subsystems and to connect them via reversible or irreversible interactions. The modeling of heat engines had to be extended by heat losses and finite rates in order to leave the field of ideal and reversible processes and achieve a better description of real processes occurring in finite time. What is commonly referred to as finite time thermodynamics became increasingly important as early as the 1970s. By way of example, the modeling of an AC motor and its loss fluxes and entropy production rates are shown. On the other hand, we can use it to build an endoreversible engine setup that is suitable to model engines with given efficiencies or efficiency maps and, among other things, gives an expression for their entropy production rates. On the one hand, this allows the modeling of leakages and friction losses, for instance, which can be represented as leaky particle or torque transfers. To do this, in the first step, we introduce a more general interaction type where energy loss not only results from different intensive quantities between the connected subsystems, which has been the standard in endoreversible thermodynamics up to now, but is also caused by an actual loss of the extensive quantity that is transferred via this interaction. In order to give an opportunity to incorporate dissipative engines with given efficiencies into an endoreversible model, we build a new dissipative engine setup. ![]() This gives a framework where irreversibilities and thus entropy production only occur in interactions, while subsystems (engines, for instance) act as reversible. Endoreversible thermodynamics is a finite time thermodynamics ansatz based on the assumption that reversible or equilibrated subsystems of a system interact via reversible or irreversible energy transfers. ![]()
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