PESWiki.com -- Pure Energy Systems Wiki:  Finding and facilitating breakthrough clean energy technologies.







    

PowerPedia:Radiant Energy

From PESWiki

(Redirected from Radiant energy)
Jump to: navigation, search
See also: Directory:Radiant Energy


Radiant energy is the energy of electromagnetic waves. Radiant energy exists in a range of wavelengths that extends from Extremely Low Frequency (ELF) to gamma rays. The term is most commonly used in the fields of radiometry, solar energy, heating and lighting, but is also used less frequently in other fields (such as telecommunications). The quantity of radiant energy may be calculated by integrating radiant flux (or power) with respect to time and, like all forms of energy, its SI unit is the joule. In applications involving transmission of power from one location to another, "radiant energy" is sometimes used to refer to the electromagnetic waves themselves, rather than their energy (a property of the waves).

Radiant energy is one of the energy sources that can be used to power an open system. Such an open system can be man-made (such as a solar energy collector), or natural, such as the Earth's atmosphere. In geophysics, transparent greenhouse gases trap the sun's radiant energy (at certain wavelengths), allowing it to penetrate deep into the atmosphere or all the way to the Earth's surface, where they are re-emitted as longer wavelength radiation (chiefly infrared radiation). Radiant energy is produced in the sun as a result of nuclear fusion.

Radiant energy, as well as convective and conductive energy, is used for heating homes. It can be generated electrically by infrared lamps, or can be absorbed from sunlight and used to heat water. Since radiant energy is really just electromagnetic radiation under another name, it is the basis of a wide range of communication technologies using radiofrequency and microwave radiation.

One of the earliest wireless telephones to be based on radiant energy was invented by Nikola Tesla. The device used transmitters and receivers whose resonances were tuned to the same frequency, allowing communication between them. In 1916, he recounted (see Anderson's book, below) an experiment he had done in 1896. He recalled that "Whenever I received the effects of a transmitter, one of the simplest ways [to detect the wireless transmissions] was to apply a magnetic field to currents generated in a conductor, and when I did so, the low frequency gave audible notes."

The United States Patent Offices has a classification of radiant energy for patent applications (Class 250, a residual class for methods and apparatus involving radiant energy). This class provides for all methods and apparatus for using, generating, controlling or detecting radiant energy, combinations including such methods or apparatus, subcombinations of same and accessories therefore not classifiable elsewhere by the patent office.

Terminology

Quantity - Symbol - SI - unit - Abbr. - Notes

  • Radiant energy Q joule J energy
  • Radiant flux Φ watt W radiant energy per unit time, also called radiant power
  • Radiant intensity I watt per steradian W·sr^−1 power per unit solid angle
  • Radiance L watt per steradian per square metre W·sr^−1·m^−2 power per unit solid angle per unit projected source area. Sometimes confusingly called "intensity".
  • Irradiance E watt per square metre W·m^−2 power incident on a surface. Sometimes confusingly called "intensity".
  • Radiant emittance / Radiant exitance M watt per square metre W·m^−2 power emitted from a surface. Sometimes confusingly called "intensity".
  • Spectral radiance Lλ or Lν watt per steradian per metre3 or watt per steradian per square metre per Hertz W·sr^−1·m^−3 or W·sr^−1·m^−2·Hz^−1 commonly measured in W·sr^−1·m^−2·nm^−1
  • Spectral irradiance Eλ or Eν watt per metre3 or watt per square metre per hertz W·m^−3 or W·m^−2·Hz−1 commonly measured in W·m^−2·nm^−1
Radio spectrum
ELF SLF ULF VLF LF MF HF VHF UHF SHF EHF
3 Hz 30 Hz 300 Hz 3 kHz 30 kHz 300 kHz 3 MHz 30 MHz 300 MHz 3 GHz 30 GHz
30 Hz 300 Hz 3 kHz 30 kHz 300 kHz 3 MHz 30 MHz 300 MHz 3 GHz 30 GHz 300 GHz

  • extremely low frequency ELF
  • super low frequency SLF
  • ultra low frequency ULF
  • very low frequency |VLF
  • low frequency LF
  • mediumwave MF
  • high frequency HF
  • very high frequency VHF
  • ultra high frequency UHF
  • Microwave SHF
  • extremely high frequency EHF

Resources and external articles

Nikola Tesla
T. Henry Moray
Regulations
Patents
Other
  • Caverly, Donald Philip, "Primer of electronics and radiant energy" New York, McGraw-Hill, 1952.
  • Hardis, Jonathan E., "Visibility of Radiant Energy". (PDF)
  • "Radiant Energy". Lighting Design Knowledgebase. (Term of radiometry)
  • Anderson, Leland I. (editor), Nikola Tesla On His Work With Alternating Currents and Their Application to Wireless Telegraphy, Telephony and Transmission of Power, 2002, ISBN 1893817016
  • Clear Tech Inc. - Dr. Peter Lindemann's site about how Nikola Tesla discovered the effect, back in 1889, and named it "Radiant Energy."
    • Peter A. Lindemann, D.Sc., "The Free Energy Secrets of Cold Electricity". (Video)
    • Peter A. Lindemann, D.Sc., "The Free Energy Secrets of Cold Electricity". (Book)
    • Dr. Lindemann, "The Radiant News". - back-issues for sale

Adapted from the Wikipedia article, "Radiant energy", used under the GNU Free Documentation License.

See also

Directory:Power from Ambient Electromagnetic Radiation

- PowerPedia main index
- PESWiki home page

Personal tools

Departments
Sponsored Links

Support
Toolbox