UO Solar Radiation Monitoring Laboratory

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SRML Glossary — "S"

Special thanks to NREL

We'd like to thank the National Renewable Energy Laboratory for making available to us their glossary, which is the basis of ours. We've edited and reformatted it, and linked it to our Web pages, and we'll continue to add our own specialized terms, illustrations, and examples. Please note that the Solar Radiation Monitoring Laboratory takes full responsibility for any inaccuracies that may occur.

Links to other glossary sections:

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


Saturated Air
 
  Air that has the maximum amount of water vapor; any increase in water vapor will cause condensation.
Scattered Radiation
 
  Radiation that has been reflected from particles, disrupting the original direction of the beam.

Click Shining On (Figure 3) to see solar components


Semiconductor
 
  A material that has much lower resistance to the flow of electrical current in one direction than in another. Diodes, transistors, and many photovoltaic cells contain semiconductive materials.
SERI
 
  The Solar Energy Research Institute, which became the National Renewable Energy Laboratory in 1991.
Shading Disk
 
  A disk on a tracking arm which blocks the direct normal irradiance so as to allow a pyranometer to measure only the diffuse sky radiation. Below is a picture of a pyranometer shaded by a shading disk.

   


Shadow Band
 
  A metal strip which blocks the direct normal radiation so as to allow a pyranometer to measure only the diffuse sky radiation. Below is a picture of a pyranometer shaded by a shadow band.

   


Shortwave Radiation
 
  The principal portion of the solar spectrum that spans from approximately 300 nanometers (nm) to 4000 nm in the electromagnetic spectrum. Longwave radiation is infrared radiation (>4000 nm).
Silicon Sensor
 
  A photovoltaic cell that is being used to measure solar irradiance. Because its spectral response is not as exact as that of thermopile instruments, it has a higher uncertainty.
Sky Dome
 
  Refers to the appearance of the entire sky, from horizon to zenith in all directions. Below is a picture of the sky dome at the Solar Radiation Research Laboratory taken by an all-sky camera.

   


Sky Radiation
 
  Synonymous with diffuse sky radiation, the radiation component that strikes a point from the sky, excluding circumsolar radiation. In the absence of atmosphere, there should be almost no sky radiation. High values are produced by an unclear atmosphere or reflections from clouds.

Click Shining On (Figure 3) to see solar components


Solar Cell
 
  A photovoltaic cell that is used to convert solar energy into electricity.
Solar Collector
 
  A device that receives solar energy and converts it to useful energy forms. The following figure from Shining On illustrates several types of solar collectors.


Solar Concentrator
 
  A solar collector that enhances solar energy by focusing it onto a smaller area through mirrored surfaces or lenses.
Solar Constant
 
  Although not strictly constant, this number is the amount of solar power flux that passes through the mean Earth orbit. The currently accepted value is 1367 W/m2. Note that Earth-based instruments record lower values of solar power flux because of atmospheric attenuation.
Solar Conversion Technologies
 
  Collective name for all methods for converting the sun's energy into usable energy.
Solar Detoxification
 
  Technology for using concentrated sunlight to break down and destroy hazardous waste.
Solar Electric
 
  Technology for converting sunlight directly into electricity.
Solar Energy Technology
 
  Method for harnessing, storing, and using the sun's energy.
Solar Fuel Technology
 
  Methods for converting biomass into fuels and by-products.
Solar Heat
 
  Technology to harness the sun's energy for heating buildings, air, and water for industrial and household uses.
Solar Irradiance
 
  The amount of solar energy that arrives at a specific area of a surface during a specific time interval (radiant flux density). A typical unit is W/m2.
Solar Noon
 
  The time at which the position of the sun is at its highest elevation in the sky. At this time, the Sun is either due South (typically in the Northern Hemisphere) or due North (typically in the Southern Hemisphere). This time can be quite different from noon according to local standard time.
Solar Radiation
 
  The electromagnetic radiation emitted by the sun.
Solar Spectrum
 
  The electromagnetic spectral distribution emitted by the sun or received by a collector or instrument on Earth. For example, Figure 2 from Shining On below shows the solar spectrum as measured in space and on the Earth's surface.


Solar Thermal Electric
 
  Technology for using the sun's energy to produce steam to run turbines that generate electricity.
SOLMET
 
  The 26 measurement sites in the 1952-1975 SOLMET/ERSATZ solar & meteorological hourly network that measured global horizontal solar radiation. The SOLMET/ERSATZ network has been replaced by the 1961-1990 National Solar Radiation Data Base.
Spatial
 
  Pertaining to space, or pertaining to distance such as spatial variation (variation over distance).
Spectral Distribution
 
  The solar spectral distribution.
Spectral Irradiance
 
  The amount of radiant energy flux expressed in terms of the solar spectrum. NREL's Solar Spectral Radiation Data Base contains thousands of irradiance spectra.
Spectro-
radiometer
 
  An instrument designed to measure spectral irradiance. Spectroradiometers gathered the data in NREL's Solar Spectral Radiation Data Base.
SRRL
 
  The Solar Radiation Research Laboratory at the National Renewable Energy Laboratory.
Stratosphere
 
  The relatively isothermal (constant temperature) layer of the atmosphere above the troposphere and below the mesosphere.
Sunshine
 
  Used interchangeably with the more precise term bright sunshine, when the sun casts an obvious shadow or when a Campbell-Stokes sunshine recorder is recording, usually above 210 W/m2.
Sunshine Duration
 
  The length of time for which the sun casts an obvious shadow or when a Campbell-Stokes sunshine recorder is recording. The lower limit for bright sunshine (based on a Campbell-Stokes recorder) is between 70 W/m2 (very dry air) and 280 W/m2 (very humid air).
Sun Position
 
  The location of the sun in the sky, expressed in terms of azimuth angle and zenith angle.
Suns
 
  A unit which multiplies the amount of energy the Earth can receive from the sun, typically used by the solar concentrator community; e.g., a concentrator might focus the energy of 40 suns onto a central receiver. Note that this unit is not precisely defined, and is usually less than the solar constant.
   
Links to other glossary sections:

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

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© 2000, UO Solar Radiation Monitoring Laboratory.
Last revised: December 11, 2000.


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