glossary of terms   [A] [B] [C] [D] [E] [G] [H] [I] [L] [M] [N] [O] [P] [R] [S] [T] [U] [V] [W] [Z]
term definition {symbol} [units]		German translation
absorptance ratio of absorbed to incident radiation on a surface (a.k.a. absorption factor) [--]		Absorptions- grad
absorption factor -- see absorptance
albedo -- see ground-reflectance		Albedo
altitude distance above (or below) sea level of a geographic location [m]		Seehöhe
ambient air temperature design temperature of the air in the space surrounding any object being considered (e.g., a building, a thermal energy storage device, or a solar collector) [°C]		Außenluft- temperatur
angle factor -- see view coefficient
angle of incidence angle between the line joining the center of the solar disk to a point on an irradiated surface and the outward normal to the irradiated surface (a.k.a. incidence angle, incident angle) [--]		Einfallswinkel
(glazed) aperture opening in an exterior wall surface (solar collector), through which unconcentrated solar radiation is admitted		(verglaste) Öffnung
aperture area area of a transparent component of a building surface (the maximum projected area through which unconcentrated solar radiation enters a collector) [--]		Verglasungs- fläche (Öffnungsfläche)
atmospheric attenuation decrease in the irradiance (and shift in its spectral distribution) of solar flux while propagating through the atmosphere due to absorption and scattering by the atmospheric constituents		Abschwächung durch die Atmosphäre
atmospheric radiation longwave radiation emitted by and propagated through the atmosphere (a.k.a. sky radiation)		Gegenstrahlung der Atmosphäre
auxiliary heat source source of heat (other than solar) used to supplement the output provided by the solar energy system		(Zusatz-) Wärmequelle bzw. Beheizung
auxiliary heating energy demand load applied to the auxiliary heat source [--]		(Zusatz-) Heizwärme- bedarf
azimuth angle between due south and the horizontal projection of the normal vector of a surface plane [--]		Flächenazimut
beam radiation -- see direct radiation		direkte Strahlung
conduction transfer of energy (heat) from a warmer to a colder region in a material medium, whereby kinetic energy is transmitted between particles without material displacement		Wärmeleitung
convection heat transfer between a surface and an adjacent fluid medium (usually air or water) as well as by fluid displacement		Konvektion
date (day) day of year / [M/D], [day #]		Datum (Tag)
daylight -- see visible solar radiation		Tageslicht
diffuse (solar) radiation combined quantity of diffuse sky and (ground-)reflected solar radiation received on a plane surface [W/m2], [W]		diffuse Strahlung
diffuse (ground-)reflected radiation solar radiation received on a plane surface that is diffusely reflected by surrounding surfaces (terrain) [W/m2]		diffuse Reflexstrahlung (der terrestrischen Umgebung)
diffuse sky radiation solar radiation received on a plane surface that is scattered in the atmosphere [W/m2]		diffuse Himmelsstrahlung
direct (beam) radiation radiation received on a plane surface i from a small solid angle centered on the sun's disk (a.k.a. beam radiation) [W/m2], [W]		direkte Strahlung
directional transmittance transmittance per unit interval of incident angle (a.k.a. incident angle response) [--/°]		einfallswinkel- abhängiger Transmissions- grad
ecliptic longitude angular position of the earth in its orbit around the sun (measured from the spring equinox position) [°]		ekliptische Länge
emission radiant exitance of a body at a given temperature		Abstrahlung
emissivity -- see emittance
emittance ratio of radiation emitted by a body to the emission of a full radiator (blackbody) at the same temperature (a.k.a. emissivity) [--]		Emissionsgrad
Equation of Time time adjustment applied to local and mean solar time to account for certain irregularities in the daily rotation of the earth about its axis over the course of the year. [--]		Zeitgleichung
extraterrestrial solar radiation solar radiation received at the limit of the earth's atmosphere [W/m2]		extraterres- trische Strahlungs- intensität
geographic location terrestrial position on the globe, expressed as latitude/longitude / [°]		geographische Lage, Standort (Breite/Länge)
global (solar) radiation combined quantity of direct, diffuse sky, and diffuse reflected solar radiation received on a plane surface from a solid angle of 360°, integrated over all wavelengths (a.k.a. total incident radiation) [W/m2], [W]		globale Sonnenstrahlung
Greenwich mean time international reference time scale, based on the time zone meridian at longitude 0° (Greenwich meridian) GMT [h]		Greenwich- Zeit
ground-reflectance average reflectance of the terrestrial surroundings at a given geographic location (a.k.a. albedo) [--]		Reflexionszahl der terrestrischen Umgebung
haziness factor atmospheric parameter (Linke), used together with site altitude to describe the effect of local meteorological conditions on the quantity of direct solar flux passing through the atmosphere [--]		Trübungsfaktor (Linke)
heat flow energy transfer through various materials and structures (usually refers to conduction, convection, and radiation combined) [W]		Wärmefluß
heat transfer coefficient any one of a number of coefficients used in calculating heat flow by through various materials and structures (total, conductive, and radiative heat transfer coeff.) , , [W/m2K]		Wärmeübergangs- zahl (Gesamt- bzw.für Konvektion und Strahlung
horizon elevation effective extent of a distant-field obstruction, expressed as the angular elevation of the horizon at an azimuth measured from the center of a site location (assumed for an azimuth interval) / - [°]		Horizont- überhöhung
incident angle response -- see directional transmittance
infrared radiation (IR) radiation of wavelengths between 780 nm and app. 1 mm [W/m2]		infrarot Strahlung
infrared transmittance ratio of the infrared radiation transmitted through a body to the incident radiation in the same range [--]		Infrarot- transmissionsgrad
internal gains energy dissipated as heat inside a space by occupants (body heat) and appliances (lighting, electrical equipment, etc.) [W] [Wh]		Innenwärmen (Wärmequellen)
irradiance -- see specific flux		Bestrahlungs- dichte
irradiation incident energy per unit area of incident surface, found by integration of irradiance over a specified time interval (usually an hour or a day) [Wh/m2] [MJ/m2]		Bestrahlung
light -- see visible radiation		Licht
light transmittance -- see visible transmittance		Lichttransmissionsgrad
load heat supplied to the user (positive value: heating load; negative value: cooling load) [Wh] [MJ]		(Energie-) Bedarf
local time hour of day as determined by the time zone convention of the geographic location [h]		Zonenzeit
longwave radiation radiation at wavelengths greater than 3 mm, typically originating from sources at terrestrial temperatures (e.g., ground and other terrestrial objects) [W/m2]		langwellige Strahlung (Wärmestrahlung)
luminous flux -- see visible radiation		sichtbare Strahlung (Licht)
mean solar time hour of day as determined by the apparent angular motion of the sun across the sky, with solar noon as the reference point for 12 o'clock [h]		wahre Ortszeit
natural light -- see visible radiation		natürliches Licht
(solar) obstruction anything outside a building which prevents the direct view of part of the sky (distant-, middle-, and near-field obstructions treated separately)		beschattender Gegenstand
optical air mass measure of the length of the path through the atmosphere to the earth's surface traversed by extraterrestrial solar radiation, expressed with reference to the path length in the vertical (varies with the declination of the sun and site altitude, as well as local barometric pressure -- to be distinguished from meteorological air mass) [--]		relative Luftmasse
orientation direction that a surface plane faces, expressed as the azimuth and tilt angles of the plane's normal vector / [°]		Orientierung
overall U-value resultant average U-value over the extent of a thermal envelope [W/m2K]		mittlerer Wärmedurchgangs- koeffizient (k-Wert)
perihelion point in the earth's orbit when it is closest to the sun (at ~147 x 106 km)		Perihel
primary gain solar radiation transmitted directly through a glazed aperture [W], [Wh]		primäre Strahlungstrans- mission (durch Verglasung)
pyranometer radiometer designed for measuring the irradiance on a plane receiver surface which results from the radiant flux incident from the hemisphere above (within the shortwave range 0.3 - 3 µm) -- see also solar radiation		Pyranometer
radiant air temperature hypothetical temperature at an exposed surface, calculated to account for solar absorptance of shortwave radiation, exchange of longwave emission with the sky and ground, as well as forced convection due to wind at a given ambient air temperature (similar to sol-air temperature) [°C]		Strahlungs- lufttemperatur
radiant flux quantity of energy transferred by radiation , [Wh] [MJ]		Strahlungs- energie
radiation transfer of energy in the form of electromagnetic waves or associated photons		Strahlung
reflectance ratio of the radiant flux reflected from a surface to the incident radiation (a.k.a. reflection factor) [--]		Reflexions- grad
reflection factor -- see reflectance
resultant air temperature average radiant air temperature over the extent of a surface area of uniform orientation and solar absorptance, calculated to account for (partial) obstruction of direct beam radiation [°C]		resultierende (Strahlungs-) Lufttemperatur
resultant (solar) flux incident radiation on the extent of a surface area, calculated to account for (partial) obstruction of the direct beam [W], [Wh]		resultierende Strahlungs- leistung (Stahlungs- wärmestrom)
scatter factor atmospheric parameter (Reitz), used together with the haziness factor (Linke) to describe the effect of local meteorological conditions on the diffuse sky component of solar flux passing through the atmosphere [--]		Faktor der diffusen Himmels- Strahlung (Reitz)
scattering interaction of radiation with matter where its direction is changed, but the total energy and wavelength remain unaltered		Streuung
secondary gain solar radiation absorbed and re-emitted to the interior through a glazed aperture [W], [Wh]		sekundäre Wärmeabgabe (Verglasung)
selective surface surface of which the properties of reflectance, absorptance, transmittance, and emittance vary with the wavelength of incident radiation		selektive öberfläche
shading coefficient (SC) ratio of solar heat gain through a glazing system under a specific set of conditions to solar gain through a single light of the reference glass under the same conditions (related to total solar energy transmittance)
shortwave radiation radiation with wavelengths less than 3 µm (includes ranges of ultraviolet and visible radiation) [W/m2]		kurzwellige Strahlung
sky radiation -- see atmospheric radiation
sky temperature equivalent blackbody radiation temperature of the atmospheric longwave radiation received at a horizontal surface [°C]		Gegenstrahl- ungstemperatur der Atmosphäre
sol-air temperature -- see radiant air temperature		"Sonnenluft- temperatur"
solar absorptance -- see absorptance		Absorptions- grad für Sonnenstrahlung
solar altitude -- see solar elevation
solar azimuth projected angle between a straight line from the apparent position of the sun to the point of observation and due south (west positive) [°]		Sonnenazimut
solar (thermal) collector building component or device designed to absorb solar radiation and to transfer thermal energy so gained to an interior space or a fluid passing through it		Solarkollektor
solar constant solar flux outside the earth's atmosphere on a plane normal to the direction of this radiation when the earth is at its mean distance from the sun (149.5 x 106) - defined as 1367 W/m2 (but may be revised within ±7 W/m2) [W/m2]		Solarkonstante
solar contribution heat supplied by the solar part of a system [Wh] [MJ]		solarer Beitrag
solar declination angle subtended between the earth-sun line and the plane of the equator (north positive, 0° on equinox dates, varying between ±23.45° on solstice dates) [°]		Sonnen- deklination
solar direct transmittance -- see transmittance		direkter Sonnenenergie- transmissions- grad
solar elevation angle between the line joining the center of the solar disk to the point of observation and the horizontal plane through the point of observation, corrected for refraction through the earth's atmosphere (a.k.a. solar altitude -- the term elevation is preferred here in order to distinguish this angular dimension from the linear distance of site altitude) [°]		Sonnenhöhe
solar energy energy emitted by the sun in the form of electromagnetic energy or any energy made available by the reception and conversion of solar radiation [Wh] [MJ]		Sonnenenergie
solar flux radiation emitted by, transferred or received from the sun [W/m2], [Wh/m2]		Sonnenbe- strahlung bzw. -einstrahlung
solar flux envelope specific flux on (or irradiation of) an ideal tracking surface, i.e. global flux at a normal angle of incidence [W/m2], [Wh/m2]		Strahlung auf eine nach- geführte Fläche
solar (savings) fraction energy supplied by the solar part of a system divided by the total system load [--]		solarer Beitragsanteil am Gesamt- energiebedarf
(direct) solar gain net solar flux that passes into the interior through transparent components of a building's thermal envelope (e.g., glazed apertures) [W], [Wh]		solare Gewinne
solar gain factor -- see total solar energy transmittance		Gesamtenergie- durchlaßgrad
solar heat gain factor (SHGF) specified condition for calculating solar gain through a glazing system using shading coefficients (SC)
solar noon local time of day when the sun crosses the observer's meridian [h]		wahrer Mittag
solar path diagram graphic representation of solar azimuth versus solar elevation, showing the position of the sun as a function of time for various dates of the year (a.k.a. sun-path diagram)		Polardiagramm (Sonnenbahn- diagramm)
solar position location of the sun in the sky hemisphere, expressed as solar azimuth and elevation angles / [°]		Sonnenstand
solar radiation -- see also solar flux radiant flux emitted by the sun (primarily in the shortwave range 0.3 - 3.0 µm) [W] [Wh] [MJ]		Sonnen- strahlung
solar spectrum distribution by wavelength (or frequency) of solar radiation		Sonnen- strahlungs- spektrum
solar time -- see also mean solar time		wahre Ortszeit
solar zenith angle angular distance of the sun from the vertical, i.e. the angle subtended by a vertical line to the zenith and the line of sight to the sun (90° complement of solar elevation) [°]		Zenitwinkel
specific (solar) flux power or energy density of solar radiation incident on a surface, i.e. the rate or quantity at which radiant flux is incident on a surface per unit area of that surface (a.k.a. irradiance) [W/m2], [Wh/m2]		Bestrahlungs- dichte
spectral (solar) flux solar radiation per unit interval of wavelength [W/m2.µm]		spektrale Strahlungs- leistung
spectral irradiance -- see spectral flux
spectral transmittance transmittance per unit interval of wavelength [--/µm]		wellenlängen- abhängiger Transmissions- grad
specular surface surface with reflective properites where the angle of visible incidence is equal to the angle of reflection (in this context: all surfaces assumed to be uniformly diffuse-reflecting)		spiegelnde Oberfläche
sun-path diagram -- see solar path diagram		Polardiagramm
sunspace solar collector that shares at least one common wall with the associated building and doubles as useful building space		Wintergarten
surrounding air speed air speed (velocity) measured in a specified location near an exposed surface (e.g., a solar collector or system) -- primarily influences convection (heat transfer coefficient) [m/s]		Wind- bzw. Luft- geschwindigkeit
temperature thermal state of matter with reference to its tendency to communicate energy (heat) to other matter by radiation exchange, conduction, or convection [°C] [K]		Temperatur
temperature zone space thermally distinguished by the assumed air temperature (boundary condition node of the thermal network model)		(Temperatur-) Raum
thermal conductance time rate of heat transferred through a composite structure separating two temperature zones (for planar components: product of U-value and area) [W/K]		(Wärme-) leitwert
thermal (building) envelope composite structure of building elements that separate an interior temperature zone from the exterior		thermische Gebäudehülle
tilt angle between the horizontal plane and the normal vector of a surface plane [°]		Flächenneigung
time zone meridian reference longitude for adjusting mean solar to local time [°]		Bezugsmeridian der Zeitzone
total incident radiation -- see global solar radiation		globale Sonnenstrahlung
total solar energy transmittance ratio of the total solar energy transmitted through glazing (including longwave re-radiation to interior) to the incident radiation (a.k.a. solar gain factor, also related to shading coefficient) [--]		Gesamtenergie- durchlaßgrad
tracking collector solar collector that moves so as to follow the apparent motion of the sun during the day, rotating about one or two axes (single- or double-axis tracking)		nachgeführter Sonnenkollektor
tracking surface theoretical irradiated surface that ideally follows the path of the sun such that it is always oriented normally to the direct beam (coordinates of movement are the solar azimuth and elevation angles, angle of incidence always 0°)		nachgeführte Fläche
transmission factor -- see transmittance
transmittance ratio of the radiant flux passing through a body to the incident radiation (a.k.a. transmission factor) [--]		Transmissions- grad (Durchlaßgrad)
ultraviolet radiation (UV) electromagnetic radiation with wavelengths shorter than visible light (< 380 nm) and longer than X-rays [W/m2]		UV-Strahlung
ultraviolet transmittance (UV) ratio of the ultraviolet radiation transmitted through a body to the incident radiation in the same range [--]		UV-Trans- missionsgrad
U-value heat flow through unit area of a planar component of the thermal envelope under steady conditions per unit temperature gradient maintained in the direction perpendicular to the area [W/m2K]		Wärmedurchgangs- gangskoeffizient (k-Wert bzw. flächenbezogener Leitwert)
view coefficient angular portion of the sky hemisphere to which a surface is exposed (similar to angle factor) , [--]		Einstrahlzahl
visible (solar) radiation radiation in the wavelength range that stimulates the human optic nerves, i.e. 380 - 780 nm (a.k.a. light, luminous flux) [W/m2]		sichtbare Strahlung (Licht)
visible transmittance ratio of the visible radiation transmitted through a body to the incident radiation in the same range (a.k.a. light transmittance) [--]		Lichttrans- missionsgrad
wind speed -- see also surrounding air speed air speed in meteorology [--]		Windgeschwin- digkeit
zenith highest point of the sky hemisphere, i.e. the point vertically above the observer		Zenit

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© M. Rudy (2001)