A Müser-Curzon-Ahlborn engine model for photothermal conversion

We study a photothermal engine resulting from a combination of a Müser engine with an endoreversible Curzon-Ahlborn cycle. This model was proposed by De Vos as an approach to a certain class of photothermal conversion devices. We analyse that engine with and without solar concentrators. We find that typical performance quantities such as the power output, entropy production, engine efficiency and solar conversion efficiency are functions both of the collector's temperature and of the concentration factor. For the case of an engine with concentrators, we find that there is an optimum value for the concentration factor if one wishes to maximize both the solar energy efficiency and a parameter measuring a compromise between the engine's efficiency and the solar conversion efficiency.