According to TÜV Rheinland, it is now possible to perform comparison measurements much more accurately on commercially available Concentrating PV (CPV) modules, because it is possible to generate and maintain the standard temperature conditions of 25 degrees Celsius much more accurately under laboratory conditions than in natural sunlight:
“In the simulator...compact, high-intensity xenon lamps are positioned in the focal plane of a parabolic mirror. The light reflected by the mirror is just as parallel as the light from the solar disk on Earth,” explains Dr. Gerhard Mathiak, who was responsible for the development of the test stand at TÜV Rheinland.
CPV modules focus the solar radiation with lenses and mirrors to concentrate the light arriving at small, maximum-efficiency solar cells, which are otherwise only used on satellites in space, by a factor of approximately 500. This makes efficiencies of more than 30% possible, in individual cases even above 40%, though there is constant debate as to the relative merits of CPV and conventional PV technologies.
Although CPV modules require constant alignment with the sun in order to focus the light, the technology is particularly promising in regions with very high levels of direct solar radiation.
According to TÜV, one of the features of the new solar simulator is its special size. The mirror measures 1.50 m x 2.00 m, which enables a laboratory setup that is "unique in the world" and allows the accurate measurement of CPV modules up to a size of 1.80 m x 1.40 m.
At the same time, a new flash solar simulator also shortens the process for comprehensive design certification qualification in accordance with IEC 62108 for new CPV modules. The performance measurements required for the qualification can be performed much more quickly and with a higher repeatability, the company claims. This flash solar simulator can also be used to measure characteristic curves of concentrator solar cells under high light intensity in order to determine the conditions under which their performance is maximised. In this way, a surface area of five square centimeters can be homogeneously irradiated with light at a level equivalent to 100–1,500 times standard solar radiation.
The development of the new simulator was sponsored by the Ministry of Science and Research of North-Rhine Westphalia as part of the “Competence Center for Innovative Photovoltaic Module Technology NRW” (InnoPV) project.