1、Designation: E 772 05Standard Terminology Relating toSolar Energy Conversion1This standard is issued under the fixed designation E 772; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parenthe
2、ses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Referenced Documents1.1 ASTM Standards:2C 859 Terminology Relating to Nuclear Materials3D93 Test Methods for Flash Point by Pensky-MartensClosed Cup TesterE 490
3、Standard Solar Constant and Zero Air Mass SolarSpectral Irradiance TablesE 491 Practice for Solar Simulation for Thermal BalanceTesting of SpacecraftE 971 Practice for Calculation of Photometric Transmit-tance and Reflectance of Materials to Solar RadiationG 173 Tables for Reference Solar Spectral I
4、rradiances:Direct Normal and Hemispherical on 37 Tilted Surface2. Terminologyabsorberthat part of a solar collector whose primary func-tion is to absorb radiant energy and transform it into anotherform of energy.NOTE 1A thermal absorber usually possesses a solid surface throughwhich energy is transm
5、itted by thermal conduction to the transfer fluid;however, the transfer fluid itself can be the absorber in the case of anoptically transparent container and a “black liquid”. A photovoltaicabsorber converts part of the incident solar flux into electrical energy, andpart to thermal energy.absorptanc
6、e, a the ratio of the absorbed radiant or luminousflux to the incident flux. (Practice E 491). See radiometricproperties and quantities.absorptionthe process by which incident radiant energy istransformed into another form of energy by interaction withmatter.air handling unita device used for distri
7、buting conditionedair supply to a room, space, or area.air mass, AMthe ratio of the mass of atmosphere in theactual observer-sun path to the mass that would exist if theobserver was at sea level, at standard barometric pressure,and the sun was directly overhead.NOTE 2(Sometimes called air mass ratio
8、.) Air mass varies with thezenith angle of the sun and the local barometric pressure, which changeswith altitude. For sun zenith angle, Z, of 62 or less and local atmosphericpressure, P, where Pois standard atmospheric pressure, AM . sec Z(P/Po).albedothe use of the term albedo is discouraged in fav
9、or ofthe preferred term, reflectance.altazimuthal mounta supporting device that facilitatestracking of the sun and allows rotation about horizontal andvertical axes. It can be used to aim equipment such asheliostats, concentrating collectors, exposure specimens, orradiometers.angle of incidencethe a
10、ngle between a ray and the normal tothe plane on which it is incident. (The plane of incidencemay be the aperture plane, the collector, or any other planeof interest.)angle of reflectionthe angle between the direction of propa-gation of a reflected ray and the normal to the surface at thepoint of re
11、flection.angle of refractionthe angle between the direction ofpropagation of a refracted ray and the normal to the interfaceat the point of refraction.aperture areasee area, aperture.apparent solar time, aptthe hours of the day as computedfrom the position of the sun using the equation of time. (See
12、ASHRAE Handbook of Applications, 1982, Chapter 57.)area, absorberthe total uninsulated heat transfer surfacearea of the absorber, including unirradiated as well asirradiated portions.area, aperture of a flat plate collector, (1) the maximumprojected area of a solar collector through which the uncon-
13、centrated solar radiant energy may be admitted to theabsorber. (2) effective aperture areathe area as definedabove projected normal to the suns rays and corrected forany shading. Units: square metres (m2) square feet (ft2).1These definitions are under the jurisdiction of ASTM Committee E44 on Solar,
14、Geothermal and Other Alternative Energy Sources and are the direct responsibilityof Subcommittee E44.09 on Photovoltaic Electric Power Conversion.Current edition approved April 1, 2005. Published May 2005. Originallyapproved in 1980. Last previous edition approved in 2001 as E 772 87(01).2For refere
15、nced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box
16、C700, West Conshohocken, PA 19428-2959, United States.area, collector panelthe total area of the panel assembly(with its containing box, if present), projected on theaperture plane.area, gross aperture of a concentrating collector, themaximum projected area through which the unconcentratedsolar radi
17、ant energy is admitted, including any area of thereflector or refractor shaded by the receiver and its supports,and including gaps between reflector segments within acollector module.area, gross collectorthe maximum area of the completecollector module, including integral mounting means, pro-jected
18、on the aperture plane.area, net apertureof a concentrating collector, the maxi-mum projected area through which the unconcentrated solarradiant energy is admitted, excluding any area of thereflector or refractor shaded by the receiver and its supports,and excluding gaps between reflector segments wi
19、thin acollector module.auxiliary energy subsystemin solar energy applications,equipment using nonsolar energy sources to supplement orbackup the output provided by a solar energy system.beam, radiant energya collection of rays confined to aspecific path.blackbodya hypothetical “body” that completely
20、 absorbs allincident radiant energy, independent of wavelength anddirection; that is, one which neither reflects nor transmits anyof the incident radiant energy. It is the emitter of electro-magnetic radiant energy which, at a given temperature,presents the maximum spectral density of radiant exitan
21、ce orradiance at all wavelengths.NOTE 3No real material is a blackbody.Acompletely enclosed cavitywith opaque walls at a uniform temperature contains blackbody radiation.Ablackbody radiator can be approximated in the laboratory to any desireddegree of approximation by a furnace containing a cavity w
22、ith opaquewalls at a uniform temperature, that contains an aperture through whichthe blackbody radiation is observed. The degree of approximation to a trueblackbody radiator is inversely related to the ratio of the area of theaperture to the area of the interior wall of the cavity.blackbody radiant
23、energy see radiant energy, blackbody.building heat loss factora measure of the heat loss rate ofa building expressed in joules per degree day (or Btu perdegree day). This factor is multiplied by the number ofdegree days in a given period to estimate the energy requiredto heat the building during tha
24、t period.charge capacitysee thermal capacity.cloud coverthat portion of the sky which is covered byclouds, usually expressed in tenths of sky covered.collector, concentratinga solar collector that uses reflectors,lenses, or other optical elements to redirect and concentratethe solar irradiance on th
25、e collector aperture onto an ab-sorber of which the surface area is smaller than the collectoraperture area.collector effciency see efficiency, collector.collector, evacuated tubea solar collector made from trans-parent tubing (usually glass) with an evacuated space be-tween the tube and the absorbe
26、r. The absorber may consist ofan inner tube or another shape, with means for removal ofthermal energy and may be specially coated.collector, flat platea nonconcentrating solar collector inwhich the absorbing surface is essentially planar.collector, line-focusa concentrating solar collector that con-
27、centrates the solar flux in one dimension only.collector, point focusa concentrating collector that focusesthe solar flux to a point.collector, solar thermala device designed to absorb solarirradiance and to transfer the thermal energy to a fluidpassing through it.collector subsystemthat portion of
28、the solar system whichincludes the solar collectors and related piping or ducts.collector, trackinga solar collector that moves so as tofollow the apparent motion of the sun during the day,rotating about one axis or two orthogonal axes.collector, tricklea flat plate solar collector in which unpres-s
29、urized liquid flows or “trickles” over the absorber.collector cover (glazings) see cover plate, bustible liquida liquid having a flash point at or above37.8C (100F). The flash point of a liquid having a viscosityless than 45 SUS at 37.8C (100F) and a flash point below93.4C (200F) shall be determined
30、 in accordance with TestMethods D93.concentrating collector see collector, concentrating.concentration ratio, geometricthe ratio of the collectoraperture area to the absorber area.concentratoran optical device (lenses or mirrors) that, aspart of a solar collector, receives the unconcentrated solarir
31、radiance and redirects (concentrates) it to a smaller area(the receiver).conical, v over a solid angle larger than an infinitesimalelement of solid angle and less than a hemisphere. Thegeometry of the solid angle must be described in the text. Forincident beams it is assumed that the radiance is con
32、stantover the entire solid angle. (See Radiometric propertiesand quantities)containment materialin a solar energy system, a materialthat encloses the heat-transfer fluid or is in contact with theheat transfer or heat storage material, or both.convectionthe transport of heat by fluid flow.convection,
33、 forcedconvection caused by mechanical forcessuch as fans and injectors.convection, naturalconvection within a fluid, due to densitydifferences caused by temperature differences.cover plate, collectora sheet of transparent (or translucent)glazing placed above the absorber in a solar collector, topro
34、vide thermal and environmental protection.degree daysee degree day, heating and degree day, cool-ing.degree-day, cooling, (DDC or DDF, Celsius or Fahrenheitrespectively)one cooling degree-day is counted for eachdegree that the daily mean temperature is higher than a basetemperature; used to estimate
35、 energy requirements for airconditioning or refrigeration.degree-day, heating, (DDC or DDF, Celsius or Fahrenheitrespectively)one heating degree-day is counted for eachdegree that the daily mean temperature is lower than a basetemperature; used to estimate energy requirements for heat-ing.E772052des
36、ign lifethe period of time during which a system orcomponent is expected to perform its intended function,without significant degradation of performance and withoutrequiring major maintenance or replacement.diffuse, adjreferring to radiometric quantities, indicates thatthe flux propagates in many di
37、rections, as opposed to directbeam which refers to collimated flux. When referring tosolar irradiance, it is the global irradiance less the directbeam irradiance. When referring to reflectance, it is thedirectional hemispherical reflectance less the specular reflec-tance.NOTE 4Diffuse has been used
38、in the past to refer to hemisphericalcollection (including the specular component) or irradiation, with equalradiance for all directions over a hemisphere. This use is deprecated infavor of the more precise term hemispherical.directionalover an infinitesimal element of solid angle in agiven directio
39、n. For properties, a solid angle small enoughthat the property does not vary within the solid angle may beconsidered an element of solid angle. Indicated by thesymbols u, F, where u is the angle between the givendirection and the normal to the sample surface, and;uf is theazimuth angle of the direct
40、ion measured counter-clockwisefrom a reference mark on the sample. See radiometricproperties and quantities.discharge capacity, thermalthe amount of heat that can beremoved from a storage device during a period of time andfor a specific set of values for the initial and final tempera-tures of the st
41、orage device, the temperature of the enteringfluid, and the mass flow rate of fluid through the storagesystem.discharge test timethe duration of a single transient test inwhich energy is removed from the storage device.distribution subsystemthat portion of the solar system fromthe storage device to
42、the point of ultimate use.drainback solar energy systemsee solar energy system,drainback.draindown solar energy systemsee solar energy system,draindown.efficiency, collectorof a solar thermal collector, the ratio ofthe amount of energy removed by the heat transfer fluid tothe solar energy incident o
43、n the collector.NOTE 5For flat-plate collectors, the value of the incident solar energyused is usually based on gross collector area; for concentrating collectorsthe value is usually based on the aperture area.efficiency, instantaneous collectorratio of the amount ofenergy removed by the heat transf
44、er fluid of a solar collectorover a specified time period (usually 5 or 15 min) to the solarenergy incident on the collector area in the same period,under steady-state or quasi-steady state.NOTE 6For flat plate collectors, the area used is usually the grosscollector area; for concentrating collector
45、s the area used is usually thegross aperture area.efficiency, period systemratio of the useful energy suppliedby the solar energy system over a period of time to the solarenergy incident on the collector area of the system in thesame period.NOTE 7The period considered has to be of a suitable length
46、for thetype of system. For example, it would not be useful to define the efficiencyof a solar space heating system over a month in the summer.NOTE 8For flat-plate collector systems, the value of incident solarenergy used is usually based on the gross collector area; for concentratingcollector system
47、s, the value is usually based on the aperture area.emissive powerthe use of the term emissive power isdiscouraged in favor of the preferred term radiant exitance.emittance, e for a sample at a given temperature, ratio of theradiant flux emitted by a sample to that emitted by ablackbody radiator at t
48、he same temperature, under the samespectral and geometric conditions of measurement. Seeradiometric properties and quantities.equatorial mounta sun-tracking mount, usually clock-driven, whose axis of rotation is parallel to that of the earth.evacuated tube collector see collector, evacuated tube.exi
49、tance, radiant see radiant exitance.exposure racks, at-latitudein solar energy applications, racksthat hold specimens at an inclination angle equal to thelatitude of the rack location, facing south.flammable liquida liquid having a flash point below 37.8C(100F) and having a vapor pressure not exceeding 40 psi(absolute) at 37.8C and shall be known as a Class I liquid.flash pointof a liquid, the minimum temperature at which itgives off vapor in sufficient concentration to form anigni
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