Browsing by Author "Valenzuela, L."
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- Ensayos de envejecimiento acelerado de reflectores solares sometidos a radiación UV y corrosiónPublication . Buendía-Martínez, F.; Fernández-García, A.; Sutter, F.; Wette, Johannes; Valenzuela, L.RESUMEN: La energía termosolar de concentración desempeña un rol fundamental en la transición energética prevista para los próximos años. La generación energética de esta tecnología depende enormemente del comportamiento óptico de los reflectores; si éste se ve mermado, el rendimiento de toda la planta solar se verá afectado. En consecuencia, utilizar un reflector adecuado puede suponer la diferencia entre el éxito o el fracaso de un proyecto. Para ciertas aplicaciones de esta energía, es necesario situar la planta solar en zonas cercanas a la costa donde la corrosividad y la dosis de radiación UV son muy elevadas. Por lo tanto, es necesario evaluar la durabilidad de los reflectores en dichos ambientes. Para ello, se han expuesto varias muestras de reflectores en Almería (España) para identificar los principales mecanismos de degradación que tienen lugar en los materiales. Además, se han realizado con éxito varios ensayos de envejecimiento acelerado que reproducen adecuadamente los principales mecanismos de degradación observados en intemperie, pero en un tiempo mucho menor. En particular, se ensayaron en condiciones aceleradas tres tipos de reflectores para evaluar su durabilidad frente a la corrosión y degradación UV.
- Influence of gaseous pollutants and their synergistic effects on the aging of reflector materials for concentrating solar thermal technologiesPublication . García-Segura, A.; Fernández-Garcia, Aránzazu; Ariza, M. J.; Sutter, Florian; Cunha Diamantino, Teresa; Martínez-Arcos, L.; Reche-Navarro, T. J.; Valenzuela, L.ABSTRACT: Concentrating solar thermal technologies have experienced an important boost in the last few years. Besides the production of electricity, they are particularly useful for the supply of industrial process heat. The industrial atmospheres affecting these solar plants typically contain gaseous pollutants that are likely to promote corrosion on the components of the solar facility, specifically solar reflectors, thereby compromising their optimal performance and the overall system efficiency. Seven accelerated aging tests were designed to study the effects of three air pollutants (H2S, SO2 and NO2) on the durability of two commercially available reflector types (silvered glass and aluminum), both in single-gas tests and in multicomponent gas mixtures. Additionally, the same material types were exposed outdoors at five representative polluted sites, including industrial, urban and coastal environments. Reflectance and optical microscope monitoring corroborated which degree of corrosion was developed on a specific type of reflector in the different tests with gaseous pollutants, as well as the synergistic effects of gas combinations. For example, tests with sulfur were harmful for silvered-glass reflectors (up to a total of 16 corrosion spots), whereas aluminum was particularly affected by tests with NO2 (numerous micro spots of around 50 pm size). Moreover, comparisons of the corrosion patterns found in accelerated-aging and outdoor exposures revealed which laboratory test reproduced the different real polluted atmospheres in the most realistic way, which is the main goal of this work. For instance, the degradation found at Site 2 was reproduced by Test NO2+SO2, with an acceleration factor of 27.