Calibration of Pyranometer

Calibration of Pyranometer

ITC is active member in calibration of pyranometer. We are capable of calibrating multiple brands and works as per established and traceable standards. ITC is here to calibrate your pyranometer.

Pyranometer is a scientific instrument used to measure solar irradiance on plane finish and even measure the solar flux density in w/sq m. It In simple words, total radiation = direct (from sun) + diffused radiation (scattered by dust, air etc).

There are 2 kinds of pyranometers:-thermopile, photodetector.

In Thermopile pyranometer the thermoelectric detection principle is used, whereby incoming radiation is almost completely absorbed by a horizontal blackened surface, over a very wide wavelength range. The resulting increase of temperature is measured via thermocouples connected in series or series-parallel to make a thermopile.

Working of Thermopile Pyranometer

Details of the high-quality pyranometer that uses a thermopile to measure solar radiation:

  1. Outer dome made from a hemisphere of optical-quality glass.
  2. Inner dome made from a smaller hemisphere of optical glass.
  3. Black carbon disk (illuminated by the Sun) absorbs a broad range of wavelengths of solar radiation and acts as the sensing element.
  4. Second, control disk (not illuminated by the Sun) acts as a comparison and compensating element. Any sources of temperature rise other than solar heat (perhaps an air-conditioning unit positioned nearby) will warm both disks equally, so we can be reasonably confident that the difference between the two disks (and the temperature rise we’re measuring) is caused only by the Sun.
  5. Thermopile temperature sensor compares the temperature rise of the two disks.
  6. Output lead (usually about 10m or 30ft long).
  7. Replaceable silica gel cartridge absorbs moisture to prevent dew forming inside on cold nights.
  8. Adjustable screw legs let you level the pyranometer using its built-in, high-precision spirit level, which is sensitive to a fraction of a degree (not shown on this diagram).