Coupled heat devices in linear irreversible thermodynamics.

Full analytical models of heat engines and refrigerators in linear irreversible thermodynamics can be defined by means of a chain of coupled heat devices. In this way it is possible to derive results and techniques of finite-time thermodynamics, like endoreversible efficiencies and the usual models of irreversible heat devices, in terms of an endoreversible energy converter plus a heat leak between external reservoirs. Also, a counterintuitive relationship is found between the global behavior of the chain and the individual performance of the devices: it is not necessary nor generally possible to impose the same operation regime on every device to achieve a desired overall performance.