Measuring Solar Radiation from Meteorology to Solar Energy Applications

Ruud Ringoir, Product Manager at Kipp & Zonen, talks to AZoSensors about measuring solar radiation from meteorology to solar energy applications.

How have Kipp & Zonen evolved to provide class-leading instruments for the measurement of solar radiation?

Kipp & Zonen has been producing instruments for Solar Radiation since 1930. In the beginning most of our instruments were used for meteorology and scientific applications. These markets require very accurate and stable instruments and data. A decade ago when the Solar Energy market started looking for radiation sensors we could offer a wide range of sensors from second class, first class to several secondary standards.

What are your key instruments for measuring solar radiation?

The key instruments for measuring solar radiation are pyranometers and pyrheliometers. In general they are used to measure: Global, Diffuse and Direct radiation.

Depending on the technology, both the pyranometer and pyrheliometer are used in Solar Energy applications. The pyrheliometer (with a sun tracker) is used to measure direct radiation as used in Solar Thermal power plants, collecting the direct radiation with concentrating mirrors. Also, concentrated PV requires the direct radiation as measured with a pyrheliometer.

The (tilted) pyranometer is used to measure the global radiation as collected by a (tilted) PV panel.

How are your instruments designed to measure solar radiation?

All our radiation sensors are based on a thermopile sensor. This is the number of thermocouples that are covered by a coating of special black paint to collect all solar energy. All collected energy is transformed into an electric voltage that is linear with the incoming radiation. These thermopile elements are covered with waterproof aluminium housings and one or two glass domes to keep them dry. The latest generation sensors even have digital interfaces and active temperature correction built in.

Can you provide examples of how you have used your instruments in solar energy projects?

Our sensors are used in many phases of solar energy projects. The first phase is prospecting, finding the optimal position of a solar power plant. The next phases where accurate measurement of solar radiation is used are; Efficiency measurement (or Bankability), Maintenance (cleaning), Ageing and failures, Calibration and finally in (PV) research to optimise and test the PV cell technology.

How has the application of your solar radiation measuring instruments helped production quality control, determination of optimum locations and predicting system output?

As indicated above. Kipp & Zonen has supplied solar radiation sensors to most of the major Solar Energy plants all over the world for both PV and CSP technologies.

Examples include the 100MW Shams power plant in Abu Dhabi, where our CHP 1 and Smart SHP1 pyrheliometers and solar trackers are used to monitor the Direct Solar Radiation. This data is used to monitor total plant efficiency.

Another example is ACCIONA Energy, one of the world’s top firms in concentrating solar power, owning a total of 264 MW of capacity in four operational plants in Spain and one in Nevada (USA). The plant in Palma del Rio, Spain has a solar field of 270 hectares with a potential of 100 MW.

Examples of our pyranometers used to monitor the global radiation for PV power plants are NREL (National Renewable Energy Lab) in USA, CIEMAT in Spain and many more.

Have these solar energy projects – using your equipment – helped drive a reduction of greenhouse gas emissions?

Solar Energy projects in general contribute to the reduction of greenhouse gas emissions. Accurate solar monitoring further contributes to the optimal use of the solar energy (prospecting and maintenance) and can check and maximise the efficiency of Solar Power plants.

CMP10 Pyranometer by Kipp & Zonen.

Can you explain how the new CMP10 and the CMP11 model work?

The new CMP10 has exactly the same physical measurement principle as the CMP 11 as described above. The great advantage of the CMP10 is that the maintenance interval is significantly enlarged. The drying cartridge in the CMP 11 that needs to be replaced every 6 – 12 months has a lifetime of 10 years in the CMP10 and is replaced during re-calibration. Both pyranometers can be combined with the new CVF4 ventilation unit that keeps the domes dry and clean for a much longer period. This makes the cost of ownership much lower due to a longer maintenance interval.

CMP11 Pyranometer by Kipp & Zonen.

What is the global reach for these products and how has the release of both instruments affected the current market with regard to competition, demand, application, maintenance, efficiency?

Both our pyranometers and pyrheliometers are used world-wide. In arctic regions, deserts or rain forests, they can be used under any atmospheric condition. Their proven reputation of reliable instruments under all conditions means that we are market leader in this segment.  There are a lot of companies that copied our sensors but quality and reliability are still highly appreciated features that make the difference.

Are you planning on implementing any further developments to these products?

We are planning to expand the Smart Interface to all our pyranometers and pyrheliometers. This implies that they will have a smart serial interface (RS-485) and a wide range of temperature correction. Further improvement of these sensors is a continuous process that will lead to interesting developments in the near future.

Where can we find further information on your products and services?

Further information can be accessed at: www.kippzonen.com/products.

About Ruud Ringoir

Ruud Ringoir is a Product Manager at Kipp & Zonen. Ruud is the interface between our R&D department and the market. He translates customer requirements into product development and is involved in every product that Kipp & Zonen launches.

Ruud has been with Kipp & Zonen for almost 35 years and is truly an expert in the instrumentation to measure solar radiation. Soon after studying electronics he started his career at Kipp & Zonen, first at the R&D department, then at sales & marketing and currently as Product Manager in this same department.