Thermal and mechanical behaviors of absorbers of different material for its application in parabolic collectors during the direct steam generation, with low mass flows $(90kg∕hto120kg∕h)$ and low pressures $(9×102kPato16×102kPa)$ were studied. The distribution of temperatures in the absorber periphery of copper, steel, and bimetallic copper-steel were analyzed using a theoretical model with the influence of a stratified two-phase flow in the internal wall of the absorber, as well as heat flux in a section of the external wall; the previous situation led to the construction of the copper-steel absorber and experimentally to a comparison with a steel absorber. In the experimental part, the thermal and mechanical analysis of the three absorbers is included, emphasizing the thickness of the wall and the thermal conductivity of each material, under the same thermohydraulic conditions. The theoretical and experimental work is analyzed for solar beam irradiance arriving from below the absorber for an east-west orientation.

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