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Arrays of coupled heat engines are proposed as a paradigmatic model to study the trade-off between individual and collective behavior in linear irreversible thermodynamics. The analysis reveals the existence of a control parameter which selects different operation regimes of the whole array. In particular, the regimes of maximum efficiency and maximum power are considered, giving for the latter a general derivation of the Curzon-Ahlborn efficiency which surprisingly does not depend on whether or not the individual engines in the array work at maximum power.

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.

Following the recent proposal by Van den Broeck for a heat engine [Phys. Rev. Lett. 95, 190602 (2005)], we analyze the coefficient of performance of a refrigerator in two working regimes using the tools of linear irreversible thermodynamics. In particular, one of the analyzed regimes gives a coefficient of performance which could be considered as the equivalent to the Curzon-Ahlborn efficiency. Also we consider the relation with the Clausius inequality, and some results for the relevant thermodynamic magnitudes in this formalism are confronted with those obtained using the finite-time thermodynamics framework.

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