SOLAR MIRRORS CHARACTERIZATION FOR CONCENTRATING SOLAR POWER TECHNOLOGY
The increasing availability on the market of different types of solar reflectors such as: polymeric film mirrors, aluminum mirrors and thin glass mirrors, together with: the lack of available norms in this area, and a valid methodology to compare the performances of the candidate reflectors; highlights the necessity to conduct a more detailed analysis on these new technologies. The objective of the present work is to suggest a valuable method to compare the reflectance performance of mirrors, evaluating also their performances in order to assess: - the most durable to ageing and weathering effects; - the different reflectance behavior with the variation of the solar incident angle. .For these reasons the work here proposed was carried out with an experimental apparatus composed by: - An Agilent Cary 5000 UV/Vis/NIR spectrophotometer to test the different performance of the mirrors at different characterization steps; - An integrating sphere of 150 mm in diameter (DRA ¡V Diffuse Reflectance Accessory); - A VASRA (Variable Angle Specular Reflection Accessory); - A UV chamber to accelerate the ageing process; - A £gScan SMS Scatterometer for RMS Roughness and BDSF measurement; - An outdoor bench The work was completed with two modeling tools: - An engineering equation solver (Mathcad) to dynamically evaluate the behavior; - A ray tracing software (Soltrace) to evaluate the system¡¦s optical efficiency. The analysis indicates that the candidate reflectors can be accurately characterized with five fundamental parameters: a) £lSWH, the solar-weighted hemispherical reflectance; b) £lSWS, the solar-weighted specular reflectance; c) £lSWS( á), the solar weighted specular reflectance function of the variable angle of incidence; d) BDSF, Bi Directional Scattering Function; e) RMS Roughness This evaluation will provide a valuable tool, for the companies who want to invest in concentrating solar power technology, to decide whether or not using a candidate reflectors to realize new plants, assessing their performances, their costs, and their durability.
Specular Reflectance, Polymeric film reflector, Aluminum reflector, Thin glass reflector, high reflective mirrors, parabolic trough, BSDF, Scatterometer, UV/VIS NIR spectrophotometer, Integrating sphere, CSP, parabolic trough, renewable energy, optical efficiency, UV ageing test solar reflector, Solar Weighted Hemispherical Reflectance, Solar Weighted Specular Reflectance, RMS Roughness, Soltrace®, Mathcad®.
Networked Digital Library of Theses and Dissertations