One type of product in which we at Apogee take particular pride is our short-wave sensors; i.e. pyranometer and quantum sensors. These rugged, optical sensors can withstand harsh outdoor environments, submersion in salt water, and are vibration tolerant. Yet, this is not enough for us.
We perform accelerated aging tests on our sensors to provide confidence in their long-term stability. Accelerated aging tests cannot directly predict the product lifetime in the field, but they do provide assurance that the product is rugged enough to withstand expected operating conditions. Accelerated aging tests often involve high levels of UV light, high temperature and humidity, high vibration, or some combination of extreme conditions. In this case we used extreme temperature cycling. We cycled a group of sensors every three hours from -20 to 60 C (-4 to 140 F). After 3 months, and more than 350 temperature cycles, the sensors did not fail.
Although our sensors are rugged, we recommend periodically, minimally every year, checking the output of radiation sensors against the sun on clear days using our free Clearsky Calculator. The user enters the location of the sensor (longitude, latitude, time zone) as well as day of year and environmental conditions and an expected output of the sensor is calculated. The sky must be clear. Our experience is that the calculated radiation intensity is within 2% of the actual solar intensity. If it does not match, the user should re-clean and inspect the sensor and again check against the Clearsky Calculator. If it still does not match then please give us a call and we can help resolve issues and, if necessary, help you get it recalibrated.
We want to ensure that we have a sensor that will continue to operate whether continuously submerged, frozen in arctic conditions or heated under the tropical sun.
Product Development Scientist