It is advised to recalibrate Pyranometer after every two years as the sensitivity of pyranometer slightly changes. The recalibration provides the proof of correct irradiance measurements. It also increases the confidence on the stability of the equipment. On re calibrating pyranometer and recieving new sensitivity certificate , one gets sure of the reliability and correctness of the instrument.
There are two methods to calibrate pyranometers . Either using Laboratory sources (Indoor) or using the sun (Outdoor) In both methods, the testing pyranometer and a reference standard pyranometer are exposed under the same conditions. ITC India Pvt Ltd has adopted the first method i.e. using Laboratory Sources and is explained below. Both the pyranometers reference and the pyranometer that has to be calibrated are exposed to a stabilized tungsten-filament lamp installed at the end of an optical bench. A practical source for this type of work is a 0.5 to 1.0 kW halogen lamp mounted in a water-cooled housing with forced ventilation and with its emission limited to the solar spectrum by a quartz window. This kind of lamp can be used if the standard and the instrument to be calibrated have the same spectral response. For general calibrations, a high-pressure xenon lamp with filters to give an approximate solar spectrum should be used. When calibrating pyranometers in this way, reflection effects should be excluded from the instruments by using black screens. The usual procedure is to install the reference instrument and measure the radiant flux. The reference is then removed and the measurement repeated using the testing instrument.
ITC India Pvt Ltd is calibrating pyranometer providing accurate and reliable results. So, do not delay in sending it to the Lab or calibrate it on site. For any qyery write us t firstname.lastname@example.org or visit www.itcindia.org