Low-Scatter Mirror Degradation by Particle Contamination

Young, R. P.

doi:10.1117/12.7972035

Cited by 46 publications

(19 citation statements)

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“…In addition to aerosols and water vapor, air borne dust has previously been shown to have detrimental impacts on PV performance [8,9], especially in favorable solar resource locations lying between latitudes 15 o and 35 o North and South of the equator [10]. Wind speed has also been shown to have a direct impact on dust particle size distributions [11][12][13], where large carbonaceous dust particles greater than 6μm can impact solar irradiance attenuation [11,12] and reduce flat-panel module performance as high as 36% [8]. In addition Gueymard found that atmospheric turbidity between a clear and hazy day, with silicate dust, can impact the DNI irradiance by as much as 20% [14].…”

Section: Introductionmentioning

confidence: 99%

Spectral derates phenomena of atmospheric components on multi-junction CPV technologies

Armijo¹,

Harrison²,

King³

et al. 2014

AIP Conference Proceedings

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Abstract. The solar spectrum varies with atmospheric conditions and composition, and can have significant impacts on the output power performance of each junction in a concentrating solar photovoltaic (CPV) system, with direct implications on the junction that is current-limiting. The effect of changing solar spectrum on CPV module power production has previously been characterized by various spectral performance parameters such as air mass (AM) for both single and multi-junction module technologies. However, examinations of outdoor test results have shown substantial uncertainty contributions by many of these parameters, including air mass, for the determination of projected power and energy production. Using spectral data obtained from outdoor spectrometers, with a spectral range of 336nm-1715nm, this investigation examines precipitable water (PW), aerosol and dust variability effects on incident spectral irradiance. This work then assesses air mass and other spectral performance parameters, including a new atmospheric component spectral factor (ACSF), to investigate iso-cell, stacked multijunction and single-junction c-Si module performance data directly with measured spectrum. This will then be used with MODTRAN5 ® to determine if spectral composition can account for daily and seasonal variability of the short-circuit current density J sc and the maximum output power P mp values. For precipitable water, current results show good correspondence between the modeled atmospheric component spectral factor and measured data with an average rms error of 0.013, for all three iso-cells tested during clear days over a one week time period. Results also suggest average variations in ACSF factors with respect to increasing precipitable water of 8.2%/cmH 2 O, 1.3%/cmH 2 O, 0.2%/cmH 2 O and 1.8%/cmH 2 O for GaInP, GaAs, Ge and c-Si cells, respectively at solar noon and an AM value of 1.0. For ozone, the GaInP cell had the greatest sensitivity to increasing ozone levels with an ACSF variation of 0.07%/cmO 3 . For the desert dust wind study, consistent ACSF behavior between all iso-cells and c-Si was found, with only significant reductions beyond 40mph.

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Section: Introductionmentioning

confidence: 99%

Spectral derates phenomena of atmospheric components on multi-junction CPV technologies

Armijo¹,

Harrison²,

King³

et al. 2014

AIP Conference Proceedings

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“…26 and in a series of papers, Technology Transfer (DCATT) principal investigator team in experRefs. 27-30, in which measurements under controlled conditions iments designed as dedicated measurements of NRER and nonreare compared with Mie scatter theory as a function of material, jected lunar radiation.…”

Section: -M1m2mentioning

confidence: 99%

Midcourse Space Experiment: Off-Axis Rejection Performance of the Infrared Sensor

O'Neil

Gibson

Richards

2006

Journal of Spacecraft and Rockets

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The public reporting burden for this collection of information is estimated to average I hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden to Department of Defense, Washington Headquarters Services Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT SPONSORINGIMONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)AFRL/VSBYB SPONSORIMONITOR'S REPORT NUMBER(S) DISTRIBUTION/AVAILABILITY STATEMENTApproved for Public Release; distribution unlimited. SUPPLEMENTARY NOTESReprinted The Spatial Infrared Imaging Telescope III (SPIRIT III) sensor on the Midcourse Space Experiment (MSX) satellite observed stray radiation from the lower atmosphere and terrestrial surface, nonrejected Earth radiance, at angles of approximately 2 to 14 deg from the optical axis in measurements of Earth limb radiance. Analysis indicates that direct scatter of terrestrial radiance from contaminants on the telescope primary mirror is the principal source of stray radiation and the bidirectional reflectance distribution function (BRDF) of the primary mirror for the 6.8-10.8-jim radiometer band is (1.11 ± 0.22) x 10-2 per sr at 1 deg off axis with an angular dependence of0-1" 71 ± 0.07.Similarly, the BRDF values for the three other LWIR radiometer bands (11.1-13.2, 13.5-15.9, and 18.2-25.1 Jim) have been determined as (1.03 ± 0.05) x 10-20-1.66 ±-0.10, (2.21 ± 0.18) x 10-20-2.04 ± 0.21, and (2.59 ± 0.02) X 10-2 o-2.10 1 0.09 sr-1 , respectively. The BRDF values derived from the on-orbit data are significantly greater than prelaunch measurements, and the increase is attributed to particulate accumulation on the primary mirror during the prelaunch period, launch, and the on-orbit telescope aperture cover removal and ejection process.

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“…Before actually calculating the BRDF by evaluating th, integral expression in Eq. (1), it is useful to plot the Integrand of the BRDF integral in Eq, (1) for selected values of 0. The integrand is a density weighted cross section given by Figure 6 shows the BRDF Integrands for the absorptive particles for the scattering angles 10 and 100.…”

Section: Brdfmentioning

confidence: 99%

<title>Exact calculation of light scattering from a particle on a mirror</title>

Johnson

1992

SPIE Proceedings

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Exact methods have been developed for calculating light scattering from particles on a perfectly reflecting surface. The computed solutions obey Maxwell's equations and the appropriate boundary conditions. A brief discussion of the theory is followed by a presentation and discussion of selected scattering results. Comparisons are made with the predictions of Young's forward scatter Mle theory model. Under certain conditions the exact results differ significantly from Mie theory. The exact differential cross sections exhibit large amplitude oscillations that are not predicted by Mile theory. The bidirectional reflectance distribution function (BRDF) Is also calculated using exact scattering theory for both spherical and hemispherical particles that are both absorptive (complex index of refraction) and nonabsorptive (real Index of refraction). These exact BRDF results are compared to the predictions of Young's model.

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Low-Scatter Mirror Degradation by Particle Contamination

Cited by 46 publications

References 0 publications

Spectral derates phenomena of atmospheric components on multi-junction CPV technologies

Spectral derates phenomena of atmospheric components on multi-junction CPV technologies

Midcourse Space Experiment: Off-Axis Rejection Performance of the Infrared Sensor

<title>Exact calculation of light scattering from a particle on a mirror</title>

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