46 year old CM5 pyranometer wins the pyranometer hunt

46 year old CM5 pyranometer wins the pyranometer huntarticle picture
Published: Wednesday, August 23, 2017 Earlier this year we opened a competition to find the oldest pyranometer still operational in the field. Now that the competition has closed and we have sorted through all the applications we can announce the winner is a CM5 from 1971. You probably want to know more, just like me, about the history of this pyranometer that originally started measuring in Canada and ended up in Germany for a second life.

An appreciated brand thanks to its history

Kipp & Zonen is a well-known name in our industry. At my very first conference for Kipp & Zonen, the EMS annual meeting in Amsterdam, I was pleasantly surprised with the number of people that knew our name and had a positive affection for it. And this has been a constant factor at every event I’ve been to. It keeps fascinating me how many people appreciate our brand and share that with us on these occasions. There is a very good reason for this besides the quality of our products: our history!

The company is 187 years old and, although it started as a pharmacy, has been in instrumentation for most of that time. The first pyranometer we manufactured was in 1923! Our instruments can be found in every region of the world, they are part of weather networks and are a reference to many scientific studies and are even in educational programs. Kipp & Zonen pyranometers have been a key input to meteorology and climatology for many years and every installed instrument tells a story.

Although we did not find a pyranometer from 1923 in the hunt, there were many entries of pyranometers with more than 25 years of operation. 

The oldest operational pyranometer found in Freiburg


The oldest entry was actually a pyranometer from 1965, but it was in storage; still working properly, but just not in the field right now. The rules of our competition specifically said it had to be operational. The winning instrument of the pyranometer hunt is very much operational, but we found out that it did spend some time in storage in its past as well.

The winner of the pyranometer hunt and owner of the 46 year old pyranometer is Anton Driesse of PV Performance Labs in Freiburg, Germany. The CM5 is part of an irradiance measurement test site and measures global solar radiation alongside a number of other pyranometers. After congratulating him, I found out more about the instrument, its journey and history.


The story of the winning CM5’s life

Anton confessed he is not the first owner of this CM5 pyranometer. In fact, while the instrument was being assembled in Delft, he was probably kicking a soccer ball around in a village just 50 km to the South, where he was born. 40 years later, while living in Kingston, Canada he spotted a CM5 on eBay. When he went to pick it up in Toronto, he found that the seller had quite a large number of pyranometers in his garage; not to mention a lot of other scientific curiosities!

The seller reported that more were on their way from Environment Canada, whose large Downsview facility was less than 10 km from his home. By the time he moved to Germany in 2011, Anton had acquired no less than 10 CM5’s, including two from 1971, and had made a long list of ideas to put them to good use again. 

The challenges of accurate irradiance measurement


Anton’s introduction to pyranometers came in 2002, when he had the task to design an innovative measurement system for a demonstration PV array. He settled on four photodiode type pyranometers for cost reasons, but did not fully appreciate the consequences of that technology choice until much later when he was analyzing and simulating the system’s performance. In 2009, both older and wiser, he founded PV Performance Labs Inc. to advise and support the nascent PV industry in Ontario. Soon after, though, he was asked to join the PV power plant group at Fraunhofer Institute for Solar Energy Systems, so he moved his family, his collection of CM5’s, and his growing list of ideas to Freiburg.

The challenges of accurate irradiance measurement were never far from his mind at Fraunhofer, and questions about the source and quality of irradiance data arose frequently in the context of system planning, performance measurement and monitoring projects.

"Solar radiation is the fuel for PV plants, therefore measuring it accurately is extremely important"

So, when Anton left Fraunhofer in 2014 and resumed his independent consulting practice, he also launched a major study of irradiance sensors to get some answers.

The PVSENSOR study


The study, called PVSENSOR to emphasize its purpose, gathered 42 sensors (21 types, including the CMP10, CMP3 and SPLite2) from a dozen manufacturers and put them through a battery of tests at the European Joint Research Centre in Ispra, Italy; as well as at Sandia National Labs in Albuquerque, New Mexico, USA, and at PV Performance Labs in Freiburg, Germany. Additional tests are currently being conducted at the National Renewable Energy Laboratory in Golden, Colorado, USA and at Germany’s national metrology institute, PTB.

With so many new instruments under observation, why is he still interested in the old CM5?

"We may have better instruments now, but we cannot use them to re-measure past conditions. On the other hand, with a better understanding of the old instruments, it may be possible to improve our understanding of those past measurements, which is exactly what we need when making plans for new PV power plants. Anyway, it’s a small additional effort to operate the CM5, and always a good topic for conversation".

Kipp & Zonen has arranged his travel and accommodation and we look forward to meeting Anton in Amsterdam!

CM5 from 1971 at the PV Performance Labs in Germany

By Kelly Dalu-KarlasMarketing Manager at Kipp & Zonen

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