The sun only has to shine

His newly developed measurement technique for characterizing solar thermal collectors earned Ing. Johann Brandmayr (31) the Innovation Award of the University of Applied Sciences of Wels. This gives Austrian Standards good reason to take a closer look at the standard-based innovation and talk with the successful developer.

Renewable energies undisputedly are a promising solution for the future of energy supply. The Climate Change and Energy Package adopted by the European Union in 2008 defined a 20 percent share of renewable energies in energy consumption as a legally binding objective. The related Austrian Climate Strategy drawn up in 2010 gives special emphasis to solar thermal energy, i.e. the conversion of solar energy into usable thermal energy.

Solar cells.
Credit: Austrian Institute of Technology

To reach the EU’s ambitious objective, energy production systems must be deployed optimally. The determination of their effectiveness and efficiency requires valid performance indicators. The basis for performance und reliability testing is laid down in the European Standard EN 12975-2 “Thermal solar systems and components – Solar collectors – Part 2: Test methods”.

The modernization of the specifications resulted in new requirements for the field testing of these products. The Upper Austrian engineer Johann Brandmayr recognized this opportunity: For the Austrian Institute of Technology (AIT), he and AIT engineer Franz Helminger developed a new, highly efficient measurement technique that provides an improved characterization of solar thermal collectors.

Certified quality is a competitive advantage

Austria is one of the leading nations in the production of solar thermal equipment. Almost one in four collectors installed in the EU is “made in Austria”, and the high quality of Austrian products is in demand world-wide. Competition, however, increases and major players enter the market. Thus, quality control and proof of verified performance data become ever more important.

Up to now, tests required considerable time and human resources. Nevertheless, it was not possible to create a really comprehensive calculation model.

Standards raise quality

Presentation of the Innovation Award to Ing. Johann Brandmayr (r.)
Presentation of the Innovation Award to Ing. Johann Brandmayr (r.)

Johann Brandmayr addressed this aspect: “Conventional methods measure the performance of a collector under almost stable conditions. The collector remains on the test stand for several days as the values measured must be constant for 10 to 15 minutes. During that period, parameters such as solar radiation, irradiation angle and cloudiness must not change. As a result, continuous monitoring is required so that testing is highly time-consuming and labour-intensive.”

ÖNORM EN 12975-2 permits testing conditions that are close to reality. Johann Brandmayr’s solar test stand for the characterization of solar thermal collector under quasi-dynamic conditions meets these requirements very well.

Brandmayr: “On account of the standard, a program had to be developed for gathering, saving and analysing the data measured. I developed the required software for my test stand, took it into operation and verified it at the Austrian Institute of Technology.”

Innovation improves efficiency

According to Dipl.-Ing. Dr. Peter Zeller who teaches at the University of Applied Sciences in Wels, the advantage of this innovation is that it allows for test automation – from loading the data from the measurement points to calculating the test results. “This significantly reduces labour intensity, while the information content of the results is optimized. Thus, Austrian solar manufacturers can be even more competitive in international markets,” explains Mr. Zeller.

The testing process itself did not change radically. The distinguishing characteristic of the new test stand is its automated operation. The previous method required optimal conditions and constant parameters, e.g. for solar radiation and cloudiness, and therefore had to be continuously monitored.

Deviations improve results

Screenshot of measurement points
Distribution of the measurement points recorded under different conditions

For the new technique, the sun only has to shine. In contrast to previous testing practice and in line with ÖNORM EN 12975-2, changing parameters are explicitly desired. Owing to the new calculation model based on multiple linear regression, deviations improve the quality of measurements since tests can be performed under real-life conditions.

Moreover, the measurement data obtained are also comparable across different testing institutes. As the system is certified under the Solar Keymark scheme of the European Committee for Standardization (CEN), it bears an internationally accepted quality label that is based on standards and the comparability of measurement results. The award-winning scientist Johann Brandmayr emphasizes that this is ultimately a must.

Brandmayr: “In order to innovate successfully, you have to rely to standards. After all, compliance with applicable standards assures the quality of products and processes and permits sustainable development and improvements.

Herbert Hirner

Bibliography

ÖNORM EN 12975-2 Thermal solar systems and components – Solar collectors - Part 2: Test methods