ASTM E892-87(1992)

ASTM E842 87 m 075951ro 0509997 080 m
Designation: E 892 - 87 (Reapproved 1992)
Standard Tables for
Terrestrial Solar Spectral lrradiance at Air Mass 1.5 for a 37O
Tilted Surface’
This standard is issued under the fixed designation E 892; the number immediately foUowing the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epdon (c) indicates an editorial change since the last revision or reapprowl.
INTRODUCTION
These tables utilize the recently revised (l)* extraterrestrial spectrum of Neckel and Labs (2) and
replace the previous standard based on Standard E490. In addition, refinements were made to
absorption and scattering calculations in the computer code (3,4) used to calculate the spectrum.
These refinements consist of a change in the depolarization factor in the Rayleigh scattering
calculation, a more accurate sampling technique for calculating scattered irradiance, and a better
choice of wavelengths to perform the calculations. Comparisons with the previous standard based
on Standard E 490 have shown that approximately a 5 % difference can exist in narrow band
widths of the spectrum, but for the integrated total little difference is apparent.
1. !kope represented by Standard E 490. The additional data points
were added to account for the solar irradiance in this region
1.1 These tables define an air mass 1.5 solar spectral
that account for approximately 1.5 % of the total irradiance
irradiance distribution for use in all solar applications where
between 0.305 and 4.045 pm. The errors propagated by
a standard terrestrial spectral irradiance is required for that
doing so are insignificant.
part of solar irradiance, diffuse, and direct, that is incident on
1.5 An air mass of 1.5, a turbidity of 0.27, and a tilt of 37’
a sun-facing, 37’-tilted surface. A similar standard for direct
were chosen for this standard because they are representative
normal irradiance is given in Standard E 89 1.
of average conditions in the 48 contiguous states of the
1.2 These tables are modeled data that were generated
United States.
using a zero air mass solar spectrum based on the revised
extraterrestrial spectrum of Neckel and Labs (l), the BRITE
2. Refereoced Documents
(3,4) Monte Carlo radiative transfer code, and the 1962 U.S.
Standard Atmosphere (5) with a rural aerosol (6, 7, 8).
2.1 ASTM Standards:
Further details are presented in Appendix Xl.
E 490 Standard Solar Constant and Air Mass Zero Solar
1.3 The air mass zero (AMO) spectrum that was used to
Spectral Irradiance Tables3
generate the terrestrial spectrum was provided by C. Frohlich
E 772 Terminology Relating to Solar Energy Conversion4
and C. Wehrli (1) and is a revised and extended Neckel and
E 89 1 Standard Tables for Terrestrial Direct Normal Solar
Labs (2) spectrum. Neckel and Labs revised their spectrum
Spectral Irradiance for Air Mass 1.54
by employing newer limb-darkening data to convert from
radiance to irradiance, as reported by Frohlich (9), citing the
3. Termioology
study by Hardrop (10). Comparisons by Frohlich with
3.1 Definitions from Terminology B 772):
calibrated sunphotometer data from Mauna Loa, Hawaii,
3.1.1 air mass (AM)-ratio of the mass of atmosphere in
indicate that this new extraterrestrial spectrum is the best
the actual observer-sun path to the mass that would exist if
currently available.
the observer were at sea level, at standard barometric
1.4 The development of the terrestrial solar spectrum data
pressure, and the sun were directly overhead.
is based on work reported by Bird, Hulstrom, and Lewis
(11). In computing the terrestrial values using the BRITE NoTE+(timetimes called air mass ratio.) Air mass varies with the
zenith angle of the sun and the local barometric pressure, that changes
Monte Carlo radiation transfer code, the authors cited took
with altitude. For sun zenith angle, 2, of 62’ or less, and local
the iterations to 2.4500 urn only. We have extended the
atmospheric pressure, P, where P, is standard atmospheric pressure, AM
spectrum to 4.045 pm using sixteen E& values from the
= set z (P/P,).
original Standard E 892 - 82. Irradiance values in Standard
3.1.2 solar h-radiance, d@bse, ES (d)-downward scat-
E 892 - 82 were computed Erom the extraterrestrial spectrum
tered solar flux as received on a horizontal surface from a
solid angle of 2x-steradian (hemisphere) with the exception
’ This standard is under the juhdiction of ASTM Committee E-44 on Solar,
of a conical solid angle with a 100 mrad (approximately 6”)
Geothermal, and other Altemative Energy Sources and is the direct responsibility
included plane angle centered upon the sun’s disk
of Subcommittee E44.02 on Environmental Parameters.
Current edition approved July 31, 1987. Published December 1987. Originally
published as E 892 - 82. Last previous edition E 892 - 82.
2 The boldface numbers in pnrentheses refer to the list of refaces at the end 3 Annual Book ofASTM Standardq Vol 15.03.
of this standard. ‘Annual Book of ASTM Stanabrds, Vol 12.02.
E 892
BSR,
6.2 The solar response R, of a device or system is the
3.1.3 solar irradiance, direct, ES-solar flux coming from
the solid angle of the sun’s disk on a surface perpendicular to weighted average spectral response with the solar spectral
the axis of that solid angle. irradiance as the weighting function as follows:
3.1.3.1 Disnrssiun-In conventional instruments the ac+
O” R(X)EAdx
ceptance cone includes a plane angle of about 6’.
s
R,= ’ ~
3.2 Descriptions of Terms Specijk to This Standard:
(2)
EMA
3.2.1 air murr zero (AMO)-describing solar radiation
s
quantities outside the Earth’s atmosphere at the mean earth-
6.3 Since the spectral re:ponse or property and the
sun distance.
spectral irradiance are not known as algebraic expressions in
3.2.2 meteorological range-distance V at which the
general, the integration must be performed as summations so
threshold contrast, t, between a black and white target is 0.02.
that Eqs 1 and 2 become, respectively,
v” =;ln;
0, = % R(X,)EA,AX, and
(3)
i-l
Therefore, V is a function only of the atmospheric extinction
coefficient U. R, = ; R( Xi)AiAXi i! E XiAhi
i-1
I
3.2.3 solar irradiance, spectral (Ex)-solar irradiance per
where:
unit wavelength interval per unit wavelength X. (Units W.
mV2*um-‘,) Xi = wavelength of the ith point out of N for which the
spectral data is known.
A=dE/dA
6.4 Weighted Ordinate Method-The summations are per-
formed as indicated in Eqs 3 and 4 by using the values of Xi,
4. Significance and Use
AX,-, and Ai given in Tables 1 and 2. Interpolation between
4.1 Absorptance, reflectance, and transmittance of terres-
nearby values of the spectral response, R(X), is often required
trial solar energy are important factors in solar thermal system
since the wavelengths of the digitally recorded response
performance, photovoltaic system performance, materials
curves may differ from those given in the table.
studies, biomass studies, and solar simulation activities. For
6.5 Selected Ordinate Method:
each of the optical properties, the initial measurements are
6.5.1 In the selected ordinate method the solar spectral
normally a function of wavelength, which requires that the
irradiance is divided into m wavelength intervals, each
spectral distribution of the solar flux be known before the
containing l/m of the total solar irradiance, E,, and having
solar weighted property can be calculated. In order to com-
a centroid wavelength Xi. This makes all the products EXjA$
pare the performance of competitive products, a single stand-
equal to E&,/m, allowing them to be factored from the
ard solar spectral irradiance distribution is desired.
summation. Equations 3 and 4 respectively reduce to the
4.2 These tables provide an appropriate standard spectral
irradiance distribution to be used in determining relative following:
performance of solar thermal, photovoltaic, and other sys-
&-Wm
0, = - m Z R(XJ, and
tems, components and materials where the direct plus d&se (5)
i-1
irradiance components are desired.
R, = IJm ; R(hi)
(6)
5. Solar Spectral Irradiice (Air Mass 1.5)
jll
5.1 Table 1 presents in tabular form that part of the solar
6.5.2 Appropriate values for the centroid wavelengths for
spectraI irradiance, diffuse and direct, from 0.305 to 4.045
100 and 50 selected ordinates are provided in Tables 3 and 4.
km that is incident on a surface tilted 37” from the horizontal
For devices with spectral responses that are relatively
toward the sun. The sun is at AM 1.5. The first column gives
smooth, the 50-point selected ordinates are adequate. For
the wavelength (X) in micrometres; the second gives the AA
devices with spectral responses that contain complex struc-
integrating interval in micrometres; the third gives the direct
ture the NO-point selected ordinate or weighted ordinate
irradiance in W .m’2*~m- I; the fourth gives the integrated
method should be used.
solar irradiance in the wavelength range from 0.3 pm to Xi in
W.mm2; and the fifth gives the fraction of the direct normal
solar irradiance in the wavelength range 0 to X,. There is an
7. Bias
insignificant amount of radiation reaching the earth’s surface
7.1 In the spectml region of interest to most solar users
below 0.3 urn. A plot of the results is shown in the Appendix.
(0.3 to 4.045 pm), the BRITE Monte Carlo computer code
has not been adequately verified with experimental data. A
6. Application
comparison of the global it-radiance resulting for this code
6.1 The output per unit area, 0, of a device or system
(for example, Standard E 892) has been compared with other
exposed to solar irradiance is the integral over wavelength of
rigorous codes. The comparison indicates that the various
the product of the appropriate spectral response, R(X) (pho-
models agree within +5 % in spectral regions where there is
tovoltaic, photochemical, optical absorptance, reflectance,
significant radiation present. Almost all of the differences in
transmittance, etc.), and the solar spectral irradiance, Eh as
the results of these rigorous codes can be traced to differences
follows:
in the molecular absorption coefficients used as input to the
0, = (ID R(X)EAdA codes.
(1)
s
ASTM Ed92 87 - 0757510 05Oqqqq 750 =
db E892
Solar S-ret Ifradiance Standard Curve for Solar Irradiance, Diffuse, and Dim in&dent on a 370 Tilted guffaw Feing the
TABLE 1
Sun With a Ground Albedo of 0.2
0.3050 9.2 0.06 0.0061 1.0406 865.5 734.21 0.7618
0.3100 40.6 0.19 o.WO2 1.0700 614.4 753.41 0.7617
0.3150 103.9 0.55 0.0006 l.lOW 397.6 768.59 0.7975
1.1206 105.8 0.8027
0.3200 174.4 1.25 0.0013 773.61
0.3250 237.9 2.26 0.0024 1.1306 182.2 775.05 0.8042
1.1376 127.4 776.13 0.8053
0.3800 381.0 3.82 0.0040
0.3350 376.0 5.72 0.0059 1.1610 326.7 781.58 0.6110
788.90 0.6186
0.3400 419.5 7.70 0.0080 1.1800 443.3
423.0 9.61 0.0102 0.2000 406.2 797.41 0.8274
0.3450
463.1
0.3500 466.2 12.03 0.0125 1.2350 812.66 0.8432
16.67 0.0175 1.2QOO 398.1 0.8678
0.3600 501.4
241.1
0.3700 642.1 22.59 0.0234 I.3200 iii:; 0.8777
29.23 0.0303 I.3500 31.3 850.02 0.8820
0.3800 686.7
0.3900 694.6 38.14 0.0375 1.3950 1.5 650.76 0.8828
44.49 0.0462 1.4425 53.7 652.07 0.6841
0.4000 976.4
0.4100 1116.2 54.96 0.0570 1.4625 101.3 653.62 0.8857
66.24 1.4778 101.7 855.09 0.8872
0.4200 1141.1 0.0687
0.4300 1033.0 77.11 0.0600 1.4978 175.5 857.66 0.8901
253.1 862.79
0.4400 1254.6 88.55 0.0919 1.5208 0.8952
1470.7 102.16 0.1060 1.5390 264.3 867.70 0.9003
0.4500
0.4600 1541.6 117.24 0.1217 1.5580 285.8 872.73 0.9056
1523.7 132.57 0.1376 1.5780 235.7 877.74 0.9108
0.4700
0.4000 1569.3 148.03 0.1536 1.5920 236.4 881.06 0.9142
0.4900 1483.4 163.30 0.1694 1.6100 220.4 885.19 0.9165
0.5000 1492.6 176.16 0.1849 1.6300 235.6 889.75 0.9232
1529.0 193.29 0.2006 1.6460 226.3 8Q3.44 0.9270
0.5100
0.5200 1431.1 206.09 0.2159 1.6786 212.5 900.46 0.9343
1515.4 0.2312 1.7408 165.3 912.18 0.9465
0.53W 222.82
0.5400 1494.5 237.67 0.2486 1.6000 29.6 918.02 0.9525
0.2624 I.8600 1.9 918.97 0.9535
0.5500 1504.9 252.67
0.5700 1447.1 262.39 0.2930 I.9200 1.2 919.06 0.9586
1.9600 20.4 919.49
0.5900 1344.9 310.30 0.3220 0.9541
0.6100 1431.5 338.07 0.3506 1.9850 87.8 920.85 0.9555
1362.1 0.38w 25.6 921.98 0.9567
0.6300 368.20 2.0050
0.6500 1366.4 393.71 0.4065 2.0350 95.9 923.81 0.9566
1341.6 2.0650 58.2 926.12 0.9609
0.6700 420.61 0.4366
0.6900 1089.0 445.12 0.4619 2.1000 85.9 928.64 0.9606
2.1480 932.80
0.7100 1269.6 468.70 0.4663 79.2 0.9677
973.7 477.67 0.4956 2.1980 68.9 936.30 0.9715
0.7160
2.2700
0.7244 1005.4 464.00 0.5022 67.7 941.22 0.9766
0.7400 1167.3 500.95 0.5196 2.3600 59.6 946.98 0.9826
0.7525 1150.6 515.44 0.5346 2.4500 20.4 950.57 0.9663
0.7575 1132.9 521.15 0.5407 2.4940 17.6 951.41 0.9872
0.7625 619.6 525.53 0.5453 2.5370 3.1 951.86 0.9877
QQ3.3 529.56 0.5495 2.9410 4.2 953.33 0.9692
0.7675
0.7600 1090.1 542.56 0.5630 2.9730 953.52 0.9894
3.w50 i:: 953.73
0.8000 1042.4 563.91 0.5651 0.9896
0.6160 616.4 576.79 0.6006 3.0560 3.1 953.97 0.9899
0.6237 756.5 564.66 0.6059 3.1320 5.2 934.29 0.9902
0.8315 883.2 591.25 0.6135 3.1560 18.7 954.58 0.9905
1.3 0.9910
0.8400 925.1 598.94 0.6215 3.2040 955.06
0.6600 943.4 617.62 0.6409 3.2450 3.1 955.15 O.QQll
699.4 636.05 0.6600 3.3178 12.8 955.71 0.9917
0.66W
0.9050 721.4 656.31 0.6610 3.3440 3.1 955.92 0.9919
12.8 956.77 0.9928
0.9150 843.3 863.13 0.6881 3.4500
0.9250 665.3 669.68 0.6949 3.5730 11.5 958.26 0.9943
0.6976
0.9300 389.0 672.31 3.7650 9.4 960.27 0.9964
0.9370 246.9 674.55 0.6999 4.0450 7.2 982.39 0.9988
963.75
0.9480 302.2 677.56 0.7031 4.0950 l.OOW
0.9650 507.7 884.46 0.7102
0.9600 623.0 692.94 0.7190
0.9935 719.7 702.00 0.7264
ASTM E892 87 - 0759.510 0510000 Obb m
@4 E 892
TABLE 2 Normalized Solar Spectral lrradiance Standard Curve (1000 W-m-‘) for Solar Irradiance, Diffuse, and Direct Incident on a 37”
lilted Surface Facing the Sun With a Ground Albedo of 0.2
NOTE-A,= wavelength, pm.
EA, =glabalsolarspectral irradiiatwavelength A,(centeredatX,andcakAatedusing absocptiondatawith a resolution of20cm-'),W~m-2q.tm-i.
E,, - A, = integrated global solar inadiance in the wavelength range 0 to A,, W-m-*.
= integrated solar irradiancx over all wavelenctths included in Table 2. Wem-*.
En - b
- -
h EA, 4 - x, fi, Al EAi Eo - A, Fh
\ 0.3050 9.5 0.06 0.0001 1.04OG 690.5 761.62 0.7618
0.3100 42.3 0.19 0.0002 1.0700 637.5 781.74 0.7817
0.3150 107.8 0.57 o.woa 1.1000 412.6 797.49 0.7975
0.3200 181.0 1.29 0.0013 1.1200 108.9 802.71 0.8027
0.3250 246.6 2.36
...