Solar Reflectance and Thermal Emittance Measurements with Field and Lab Instrumentation M. Martin Szczesniak James Jafolla Samuel Dummer
Established in 1976 to provide optical properties measurements to the military and aerospace industry. Played a major role in providing measurements to support the Optical Signature Code (OSC) used by the Ballistic Missile Defense Office in Huntsville, AL.
Core Expertise Optical Measurements Spectral Imagers Vacuum and Pigmented Coatings Reflectometers Analytical Modeling
Our mission is to supply highest quality instrumentation measuring optical properties of materials for research and commercial applications Reflectometers Group
Solar Reflectance, ) ( ) ( ) ( ) ( )* ( 2 1 2 1 = ρ ρ d J d J d s The solar reflectance of the surface may therefore be written as J() is the solar irradiance function ρ d is directional reflectance the limits 1 and 2 are 300 nm and 2500 nm
Solar Irradiance Function Measured by NASA and other science organizations, published by ASTM
Measurement of directional reflectance Cary 5000 Spectrometer Diffuse Reflectance Accessory
Integrating Sphere 6 inch ID Sample Mount
Directional Reflectance of White Knight Plus 1.0 0.9 0.8 0.7 Intensity 0.6 0.5 0.4 0.3 0.2 0.1 0.0 1000 2000 Wavelength (nm) Reflectance spectrum measured on the Cary 500.
Calculation of Solar Reflectance Intensity 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 J () ρ d () ρ s 2 1 = ρd ( )* J ( ) d( ), 2 J ( ) d( ) 1 ρs=.815 0.2 0.1 0.0 ρ ( )* J ( ) d 1000 2000 Wavelength (nm) The curves are integrated in the spectral range of 330 to 2500 nm spectral range.
Analyzed Samples
Measured Spectra
Calculated Solar Reflectance Coating Cary 5000 Cary 5000 White Knight Plus on Panel 0.815 0.82 +/-.02 White Knight Plus on Shingle 0.804 0.80 +/-.02 Pyramic on Panel 0.815 0.82 +/-.02 Pyramic on Shingle 0.816 0.82 +/-.02 White Coating 0.842 0.84 +/-.02 EPDM 0.156 0.16 +/-.02 Beige Acrylic 0.694 0.69 +/-.02 AlShingle 0.643 0.64 +/-.02 TPO 0.768 0.77 +/-.02 Shingle 0.166 0.17 +/-.02
Hand Held Reflectometer 410-Solar Developed in collaboration with NREL (Cheryl Kennedy) to measure Solar Reflectance for the needs of Concentrated Solar Power (CSP) industry.
410-Solar Specification Measured parameter: Directional Hemispherical Reflectance Measured value: Total, Diffuse and Specular Reflectance Wavelength bands: Seven bands: 330 to 2500 nm Angle of incidence: 20 from normal incidence Surface curvature: Any surface; convex 6 inch radius; concave 12 inch radius Beam spot size 0.250 Diameter at 20 Beam angle 3 Half cone angle
Data File Date/ Time Sample 335-380T 400-540T 480-600T 590-720T 700-1100T 1000-1700T 1700-2500T Solar Ref 7/12/2014 16:29 3 0.067 0.87 0.896 0.903 0.879 0.764 0.455 0.812 7/12/2014 16:29 3 0.071 0.862 0.886 0.889 0.858 0.753 0.467 0.8 7/12/2014 16:29 3 0.069 0.858 0.883 0.883 0.849 0.749 0.474 0.795 Averaged 3 0.069 0.864 0.888 0.892 0.862 0.755 0.465 0.802 StDev 3 0.002 0.006 0.007 0.01 0.015 0.007 0.009 0.009
Pyramic on Panel 1 0.9 0.8 0.7 Red line Cary 500 spectral data Rectangles 410-Solar in-band data Reflectance 0.6 0.5 0.4 0.3 0.2 0.1 0 300 800 1300 1800 2300 Wavelength [nm] The 410-Solar reproduces spectral data
Compliance ASTM E903 E 903 Test Method for Solar Absorptance, Reflectance, and Transmittance of Materials Using Integrating Spheres SolarPaces Reflectance Guidance ASTM E1549 Standard Test Method for Determination of Solar Reflectance Near Ambient Temperature Using a Portable Solar Reflectometer
SSR-ER Integrating sphere Comparison with D&S 410-Solar Integrating sphere 20 incident angle 20 incident angle Total refl. Only 4spectral bands (380, 500, 650, 1220 nm) No data storage No spectral reflectance display Power: 110 V AC Portability: semi Total, Specular, Diffuse refl 7spectral bands (from 335 to 2500 nm) Data storage Reflectance in 7 bands displayed and stored Power: 12 V battery Portability: hand held
Data Comparison Coating Cary 5000 410-Solar D&S White Knight Plus on Panel 0.82 +/-.02 0.82 +/-.02 0.82 +/-.02 White Knight Plus on Shingle 0.80 +/-.02.80 +/-.02 0.81 +/-.02 Pyramic on Panel 0.82 +/-.02.80 +/-.02 0.81 +/-.02 Pyramic on Shingle 0.82 +/-.02.81 +/-.02 0.81 +/-.02 White Coating 0.84 +/-.02.84 +/-.02 0.84 +/-.02 TPO 0.77 +/-.02.76 +/-.02 Beige Acrylic 0.69 +/-.02.70 +/-.02 0.71 +/-.02 Aluminized Shingle 0.64 +/-.02.64 +/-.02 EPDM 0.16 +/-.015.15 +/-.02 0.14 +/-.02 Shingle 0.17 +/-.015.17 +/-.02
ASTM E1549 The portable solar reflectometer is calibrated using specimens of known solar reflectance to determine solar reflectance from measurements at four wavelengths in the solar spectrum: 380 nm, 500 nm, 650 nm, and 1220 nm. This technique is supported by comparison of reflectometer measurements with measurements obtained using Test Method E 903. D&S uses spectral bands and not the listed wavelength; it is very similar to the 410-Solar as far as it operation is concerned.
Compliance Is the current D&S model compliant with the ASTM E1549? If it is then The 410-Solar is also compatible, they use the same principles of physics to perform the measurements
Total Directional Emittance FTIR Spectrometer The total directional emittanceof the surface at a given temperature is calculated by:, ), ( ), ( ) ( 1 ),, ( 0 0 = ρ φ θ ε d T P d T P d i i t P(,T) is Planck's Function for the given wavelength and temperature ρ d () is directional reflectance
Standard Reflectometer in Aerospace Industry FTIR Spectrometer SOC-100 HDR Reflectometer It measures Directional Reflectance
Opt mechanical Components of the SOC-100 Under the cover Elliptical dome over Opt. Mech.
ET100 Measurement head interchangeable with the 410-Solar head Operates in the infrared spectral range Covers 1.5 to 21 microns 6 bands
ET100 Specification Reported parameter: Emittance Method: Reflectance in a band Calculated value: Hemispherical Emittance Wavelength bands: 1.5-2.0, 2-3, 3-4, 4-5, 5-10, 10-21 Angle of incidence: 20 and 60 degrees Surface curvature: Any surface: convex and concave Measurement time: 10 seconds/measurement, user controlled (2 angles)
ET100 Data file Angle 20 Date/Time Sample 1.5-2.0 2.0-3.5 3.0-4.0 4.0-5.0 5.0-10.5 10.5-21.0 7/12/2014 13:24 4 0.531 0.194 0.054 0.059-0.011 0.17 7/12/2014 13:24 4 0.531 0.194 0.058 0.061 0.047 0.082 7/12/2014 13:25 4 0.528 0.195 0.055 0.06 0.012 0.142 Averaged 0.53 0.194 0.056 0.06 0.016 0.131 StDev 0.002 0 0.002 0.001 0.029 0.045 Angle 60 Sample 1.5-2.0 2.0-3.5 3.0-4.0 4.0-5.0 5.0-10.5 10.5-21.0 4 0.56 0.221 0.083 0.083 0.03 0.197 4 0.562 0.22 0.086 0.083 0.032 0.154 4 0.564 0.219 0.072 0.076 0.021 0.196 Averaged 0.562 0.22 0.08 0.081 0.028 0.183 StDev 0.002 0.001 0.007 0.004 0.006 0.024 Em. 20 Em. 60 Hem. E 0.942 0.917 0.897 0.94 0.916 0.894 0.941 0.925 0.896 0.941 0.919 0.896
SOC-100 and ET100 Data Comparison White Knight on Panel 0.5 0.45 0.4 Reflectance 0.35 0.3 0.25 0.2 Red line SOC-100 HDR spectral data Rectangles ET100 in-band data 0.15 0.1 0.05 0 3 5 7 9 11 13 15 17 19 21 Wavelength [µm]
SOC-100 HDR and ET100 data Coating SOC-100 SOC-100 ET100 ET100 Pyramic on Shingle 0.944 0.94 +/_.02 0.941 0.94 +/_.02 Pyramic on Panel 0.945 0.95 +/_.02 0.931 0.93 +/_.02 White Knight Plus on Shingle 0.942 0.94 +/_.02 0.926 0.93 +/_.02 White Knight Plus on Panel 0.941 0.94 +/_.02 0.935 0.94 +/_.02
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