Each sensor is calibrated in controlled laboratory conditions, traceable to the World Radiometric Reference in Davos, Switzerland. The pyranometers are cosine-corrected with directional errors less than +/- 5% at a solar zenith angle of 75 degrees. Long-term non-stability determined from multiple replicate pyranometers in accelerated aging tests and field conditions is less than 2% per year.
A patented domed-shaped sensor head (diffuser and body) facilitates runoff of dew and rain to keep the diffuser clean and minimize errors caused by dust blocking the radiation path. Sensors are housed in a rugged anodized aluminum body, and the electronics are fully potted. A heated pyranometer, P/N 10718H, is available with a 0.2 W heater to keep water (liquid and frozen) off the sensor and minimize errors caused by dew, frost, rain, or snow blocking the optical path.
Multiple analog output options are available, including 0 to 350 mV, 0 to 5.0 V, and 4 to 20 mA ranges. The silicon-cell pyranometer is also available attached to a
hand-held meter with a digital readout. These pyranometers are calibrated through side-by-side comparison to the mean of four transfer standard pyranometers (shortwave radiation reference) under high-intensity discharge metal halide lamps. The transfer standard pyranometers are calibrated through side-by-side comparison to the mean of at least two ISO-classified reference pyranometers under sunlight (clear sky conditions). Each of four ISO-classified reference pyranometers is recalibrated on an alternating year schedule (two instruments each year) at the National Renewable Energy Laboratory (NREL). NREL reference standards are calibrated to the World Radiometric Reference (WRR) in Davos, Switzerland.
- Ambient Monitoring
- Environmental Monitoring
- Climate Research
- Renewable Energy