A New Instrument for Measuring the Reflectance Distribution Function of Solar Reflector Materials

Meyen, Stephanie; Sutter, Florian; Heller, Peter; Oschepkov, Alexander

doi:10.1016/j.egypro.2014.03.227

Cited by 14 publications

(9 citation statements)

References 2 publications

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“…The first task has been accomplished quickly and with good results; the second is in stand-by, waiting for the completion of the two new instruments MIRA (DLR) [4] and VLABS (ISE) to verify the results achieved with the Solar Mirror Qualification developed by ENEA [5,6].…”

Section: Introductionmentioning

confidence: 99%

Hemispherical Reflectance Results of the SolarPACES Reflectance Round Robin

et al. 2015

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Mirrors are the first link in the energy-conversion chain from Sun to electricity-delivery in the grid. Shape and solar reflectance are the key-parameters of mirrors, respectively affecting how solar radiation is concentrated around the focus, and how much of the impinging solar power is reflected. In SolarPACES Task III, an expert group is drafting the solar reflectance guidelines; in order to speed up the discussion the SRRR round robin was launched at the beginning of 2013. Identical kits, each one consisting of ten specimens collected from eight cooperating producers, were distributed and measured at six research institutes, acting as evaluators. The kit includes both traditional (glass based) and innovative (first-surface) solar mirrors. The paper only reports on the simplest task among those of SRRR: the solar hemispherical reflectance measurement. Near-specular solar reflectance was also measured and compared but the results are still under investigation and are not part of this paper. The measurements were accomplished according to the guidelines. The differences among the achieved results are within the typical accuracy of spectrophotometers, demonstrating the reliability of the reflectance guidelines. The statistic of the deviations from the true value is analysed separately for each evaluator, and allows us to infer information abut the gauging-status of the adopted reference mirror, as well as the measurement reproducibility.

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Section: Introductionmentioning

confidence: 99%

Hemispherical Reflectance Results of the SolarPACES Reflectance Round Robin

et al. 2015

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“…In this case, a lack of commercial or validated instrumentation to adequately characterize it, according to the SolarPACES reflectance guideline, was noticed during the SRRR [3]. Some new instruments to properly measure the spectral near-specular reflectance, ρ s (λ,θ,φ), of all type of reflector materials are under development or have been recently developed by some of the institutions, such as the SMQ by ENEA [6,7], the MIRA by DLR [8,9] and the VLABS by ISE Fraunhofer [10]. Additional research work to compare the results and to establish the measurement procedure is still required.…”

Section: Introductionmentioning

confidence: 99%

Simplified analysis of solar-weighted specular reflectance for mirrors with high specularity

Fernández-García¹,

Sutter²,

Heimsath

et al. 2016

AIP Conference Proceedings

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Abstract. The most relevant parameter to properly characterize solar mirrors is the solar-weighted near-specular reflectance. As this parameter cannot be directly measured with off-the-shelf instruments, a simplified procedure to be applied for highly specular solar mirrors is proposed in this paper. The approach, based on two criteria, was experimentally employed to check a wide variety of solar reflector materials. Only those mirrors with known high specularity passed the criteria, indicating that the proposed method is suitable.

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“…DLR also has developed two other instruments. The MIRA uses the principle of a parallel imaging goniophotometer to measure near specular scatter, mapping the BRDF by means of a 180º circular fisheye lens and a CCD detector array [92], [93]. DLR has also designed an accessory for the PE Lambda spectrophotometer.…”

Section: Discussionmentioning

confidence: 99%

“…MIRA is a new prototype instrument which has been developed by DLR at the OPAC Laboratory at the PSA in 2012 to measure near specular scatter and evaluate its impact on specular reflectance [92], [93] (see Figure 33). The instrument allows the distinction of the high intensity specular peak and the low intensity scatter by taking two measurements with different sensitivity settings for the CCD chip.…”

Section: Mirror Reflectance Function Analyzer (Mira) By Dlrmentioning

confidence: 99%

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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A New Instrument for Measuring the Reflectance Distribution Function of Solar Reflector Materials

Cited by 14 publications

References 2 publications

Hemispherical Reflectance Results of the SolarPACES Reflectance Round Robin

Hemispherical Reflectance Results of the SolarPACES Reflectance Round Robin

Simplified analysis of solar-weighted specular reflectance for mirrors with high specularity

Equipment and methods for measuring reflectance of concentrating solar reflector materials

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