1、Designation:G19714Standard Table forReference Solar Spectral Distributions:Direct and Diffuseon 20 Tilted and Vertical Surfaces1This standard is issued under the fixed designation G197;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,
2、the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.INTRODUCTIONThis table of solar spectral irradiance distributions has been developed to meet the need forweighting functio
3、ns to be used in evaluating the broadband transmittance of fenestration systems orthe performance of technologies such as building-integrated photovoltaic devices.To compare therelative optical performance of spectrally sensitive products by theoretical simulation,or to comparethe performance of pro
4、ducts by actual testing under laboratory conditions,separate reference standardsolar spectral distributions for direct and diffuse irradiance are required.This table was prepared usingversion 2.9.2 of the Simple Model of the Atmospheric Radiative Transfer of Sunshine(SMARTS)atmospheric transmission
5、code(1,2).2SMARTS uses parameterizations of version 4.0 of the AirForce Geophysical Laboratory(AFGL)Moderate Resolution Transmission model,MODTRAN(3,4).An extraterrestrial spectrum differing only slightly from the extraterrestrial spectrum in ASTM E490is used to calculate the resultant spectra.The d
6、irectional beam and diffuse hemispherical(2 steradianacceptance angle)spectral irradiances on planes tilted 20(representative of a pitched roof slope)and90(tilt of a typical wall)to the horizontal are tabulated.The wavelength range for the spectra extendsfrom 280 nm to 4000 nm,covering the spectral
7、range for which windows or solar collectors respondto shortwave energy.The input parameters used in conjunction with SMARTS for each set ofconditions are tabulated.The SMARTS model and documentation are available as an adjunct to thisstandard.1.Scope1.1 This table provides terrestrial solar spectral
8、 irradiancedistributions that may be employed as weighting functions to(1)calculate the broadband solar or light transmittance offenestration from its spectral properties;or(2)evaluate theperformance of building-integrated technologies such as pho-tovoltaic electricity generators.Most of these syste
9、ms areinstalled on vertical walls,but some are also installed onpitched roofs or on other tilted structures,such as sunspaces.Glazing transmittance calculations or measurements requireinformation on both the direct and diffuse components ofirradiance.The table provides separate information for direc
10、tand diffuse irradiance,and for two different tilt angles,20 and90 relative to the horizontal.All distributions are provided at2002 wavelengths within the spectral range 2804000 nm.Thedata contained in this table reflect reference spectra withuniform wavelength interval(0.5 nanometer(nm)below 400nm,
11、1 nm between 400 and 1700 nm,an intermediate wave-length at 1702 nm,and 5 nm intervals from 1705 to 4000 nm).The data table represents reasonable cloudless atmosphericconditions favorable for the computerized simulation,com-parative rating,or experimental testing of fenestration systems.1.2 The data
12、 contained in this table were generated using theSMARTS version 2.9.2 atmospheric transmission model de-veloped by Gueymard(1,2).1.3 The selection of the SMARTS radiative model togenerate the spectral distributions is chosen for compatibilitywith previous standards(ASTM G173 and G177).The atmo-spher
13、ic and climatic conditions are identical to those in ASTMG173.The environmental conditions are also identical,withonly one exception(see sections 4.3 and X1.2).1.4 The table defines four solar spectral irradiance distribu-tions:1.4.1 Separate direct and diffuse solar spectral irradianceincident on a
14、 sun-facing,20 tilted surface in the wavelengthregion from 2804000 nm for air mass 1.5,at sea level.1These tables are under the jurisdiction ofASTM Committee G03 on Weatheringand Durability and is the direct responsibility of Subcommittee G03.09 onRadiometry.Current edition approved Dec.1,2014.Publi
15、shed December 2014 Last previousedition published 2012 as G19708(2012).DOI:10.1520/G0197-14.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 1.
16、4.2 Separate direct and diffuse solar spectral irradianceincident on a sun-facing,90(vertical)tilted surface in thewavelength region from 2804000 nm for air mass 1.5,at sealevel.1.5 The diffuse spectral distribution on a vertical surfacefacing away from the sun(i.e.,shaded),or at any prescribedazimuth away from the sun,may be computed using the modelto obtain representative results(i.e.,results that fall within anacceptable range of variance).1.6 The climatic,atmospheric,and geometric parameters