Portable Solar Spectrum Reflectometer for planar and parabolic mirrors in solar thermal energy plants

Salinas, Í.; Heras, Carlos; Alcañiz, Carlos; Izquierdo, David; Martínez, Noelia; Alonso, R.

doi:10.1016/j.solener.2016.06.010

Cited by 4 publications

(4 citation statements)

References 9 publications

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“…The regression line has been used to construct Table 2, which compares the predicted differences between the two reflectometer readings in the range 0.91-0.95 (as measured by the Condor). The Condor measures higher than the D&S by an average of 1.53%, which compares with an earlier published value of 1.35% (Salinas et al, 2016). Table 2 Reflectometer comparison (from regression line).…”

Section: Outdoor Soiling Resultssupporting

confidence: 73%

“…The Condor has a wider acceptance aperture in order to assess mirrors possessing a wider range of curvatures and thicknesses. The penalty for this is an overestimate in the measurement of reflectance, which has been estimated in previous work to be less than 1.35% (Salinas et al, 2016).…”

Section: Instrument Descriptionmentioning

confidence: 84%

“…Specular solar reflectance measurements on large solar collectors require specialist equipment, including purpose-built reflectometers. These mainly include the Abengoa Condor SR-6.1 (Martínez et al, 2012;Salinas et al, 2016), the D&S 15R-USB (Pettit, 1982;Ho et al, 2013), and the Surface Optics 410-Solar hand-held instrument (Crawford et al, 2012;Ho et al, 2013). The correct choice of instrument for on-field reflectance measurements must accomplish a set of requirements, comprising accuracy, high autonomy, easy to handle and operate, light weight, store system, with no influence from external light.…”

Section: Introductionmentioning

confidence: 99%

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Reflectometer comparison for assessment of back-silvered glass solar mirrors

et al. 2017

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This paper compares the two most common reflectometers used to assess the specular reflectance of back-silvered glass mirrors for Concentrating Solar Power (CSP) applications, namely the Device and Services (D&S) 15R-USB and the Abengoa Condor SR-6.1 instruments. Comparisons are first made between the two instruments themselves using a Gage Repeatability and Reproducibility (R&R) study. Results are given for the as-cleaned collector mirrors and then as the mirrors become naturally soiled over a one month period. The results of the Gage R&R study show that for the D&S the gage itself contributes 40.97% of the variability, whilst 59.03% is due to part-to-part (location on the mirror under investigation) variability. For the Condor we show that the % Contribution from the gage is 62.18% of the total variability with only 37.82% of the contribution attributable to the location dependent reflectance. The Condor has a wider acceptance angle, and over the reflectance range of 0.91-0.95 the condor was found to measure higher than the D&S by an average of 1.53%. The differences between the soiling results obtained from the two instruments are explained, and the results are used to derive a predictive model for the soiling of solar collectors. In conclusion, both instruments have advantages and shortcomings, and the factors that influence which instrument to select are discussed.

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Section: Outdoor Soiling Resultssupporting

confidence: 73%

Section: Instrument Descriptionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

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Reflectometer comparison for assessment of back-silvered glass solar mirrors

et al. 2017

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“…Reflector testbeds are used to study the effects of soiling in different geographical and climate regions. Multiple types of outdoor tests have been performed on reflective materials in CSP plants, including using different cleaning strategies [1,[6][7][8][9], different reflectometers [10][11][12][13], different reflective materials [4,[14][15][16][17][18][19], degradation effects from soiling [5], soiling adhesion [20,21], anti-soiling coatings [22,23], and the use of a real-time cleanliness sensor [24][25][26]. Various testbeds have been constructed to study the different effects of soiling on reflectors in different climate regions.…”

Section: Introductionmentioning

confidence: 99%

Soiling Comparison of Mirror Film and Glass Concentrating Solar Power Reflectors in Southwest Louisiana

2021

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Soiling effects influence the output of solar thermal plants, significantly causing unwanted transmittance, reflectance, and absorbance losses. Research is needed to identify what type of reflective surfaces are best suited for semitropical climates, such as the southeastern United States. This paper initially presents a review of several concentrating solar power (CSP) reflector testbeds used to analyze the soiling effects of various reflective materials. A soiling testbed is developed for this study that comprised six sets of reflective surfaces mounted at a fixed tilt of 30 degrees: three sets of thin-film surfaces and three sets of glass types. Two generations of 3M solar mirror film (SMF), 3M SMF 1100 and 3M SMF 2020, were used along with Konica Minolta SMF, silvered Corning Willow Glass, a dichroic cold mirror, and a standard mirror. Results show that the 3M SMF 2020 and Konica Minolta SMF performed the best during regular cleaning intervals, whereas the silvered Corning Willow Glass gave the best performance if only cleaned naturally. The other glass types showed the least average loss due to soiling throughout this study but gave the lowest performance for specular reflection.

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Equipment and methods for measuring reflectance of concentrating solar reflector materials

Fernández-García¹,

Sutter²,

Martínez-Arcos³

et al. 2017

Solar Energy Materials and Solar Cells

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The proper optical characterization of solar reflector materials is a challenging task. Although several commercial instruments exist to measure reflectance, they have been developed for other applications and often do not meet all the specific requirements demanded by the solar thermal industry. In particular, the characterization of solar reflectors involve the complete solar spectral wavelength range, an incidence angle range from near normal to 70°and most importantly a very narrow acceptance angle range from near specular to 20 mrad. The accurate measurement of reflectance as a function of all the previously mentioned parameters has not been commercially implemented. This paper reviews the different alternatives to measure reflector materials, describes reflectance models used to approximate the missing information and presents current research work on prototype reflectometers to fill the gap.

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Portable Solar Spectrum Reflectometer for planar and parabolic mirrors in solar thermal energy plants

Cited by 4 publications

References 9 publications

Reflectometer comparison for assessment of back-silvered glass solar mirrors

Reflectometer comparison for assessment of back-silvered glass solar mirrors

Soiling Comparison of Mirror Film and Glass Concentrating Solar Power Reflectors in Southwest Louisiana

Equipment and methods for measuring reflectance of concentrating solar reflector materials

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