Pyranometer

A pyranometer (by ancient Greek πῦρ. Pyr " fire" and οὐρανός Ouranos "heaven" ) is used to measure the incoming global solar radiation. In other words, a pyranometer is a sensor for measuring the solar irradiance (in watts per square meter) with a field of view of 180 degrees.

Pyranometer be applied in meteorology, climatology, physics and research on solar energy in many ways. They are used in meteorological stations, usually mounted horizontally and, usually mounted adjacent solar cells parallel to the surface of the solar cell. Pyranometer conform to the ISO 9060 standard, which is also recognized by the World Meteorological Organization. This Standard identifies three classes. The best class is called "secondary standard " second-best "first class " and the last "second class".

Principle of measurement

Pyranometer normally detect the out of the half-space above the sensor incoming radiation. This radiation to the visible wavelength range of the solar spectrum is called global radiation and consists of the direct solar radiation ( direct radiation ) and from the diffuse sky radiation ( diffuse radiation ). Most of the incident radiation is measured on a horizontal surface. The pyranometer consists of a cover, which protects it from environmental influences, and from a blackened thermopile. The output signal is directly proportional to the radiation intensity, which is measured in watts per square meter by means of a calibration factor. For a heat flux density or Irradiationsmessung directional response is proportional to the cosine of the angle of incidence; thus maximum response when the radiation is perpendicular to the sensor falls (perpendicular to the surface in the sun zenith, 0 degrees angle of incidence), zero response at an incident angle of 90 degrees and 0.5 at 60 degrees. It follows that a radiometer should have a so-called " directional response" or " cosine response", which is close to the ideal Kosinuscharakteristik.

Types

Pyranometer ( Standard)

The main components of a pyranometer are:

The black coating on the thermopile absorbs the solar radiation and converts it to heat. The heat is conducted through the sensor in the housing of the pyrometer. The thermopile is proportional to the radiation from an electric voltage.

A pyranometer is an active instrument; so it requires no external power source.

Albedometer or dual pyranometer

A Albedometer or dual pyranometer basically consists of two interconnected Sternpyranometern, wherein another pyranometer is installed on the back of the upward pyranometer. The thus rotated through 180 ° in the horizontal pyranometer is used to measure the reflected solar radiation.