NGlobal Magazin 01-2010

Niedersachsen Global www.nglobal.de 32 Energy It gets noisy when “artificial sun” Susi I shines in full glory. Her numerous lamps are hot inducing the fans in the Institute of Solar Energy Research’s (ISFH) test hall to turn full speed. Solar panels are enjoying the sunshine, not minding that they do so merely for test- ing purposes; at temperatures of up to 180 degrees celsius, their heat conductivity is being examined. (Sun Simulator) Susi II sits next to her, exposing the pan- els to even higher temperatures, to electrical power of 1,200 watt as well as to even more intensive UV radiation. Scientists at IFSH do seem to live on the sunny side of life. In three core areas — photovolta- ics, solar thermal and scientific services—139 of them are working on maximizing the efficient use of solar energy and new components. Metal Vapour for Thin-layer Cells In the photovoltaics section solar cells go through all stages of production until they are eventually able to supply electricity on the test roof. No matter what the function of the solar cell might later be, its basic plate — the so-called wafer — starts out in the clean room. Here everything is clinically clean, even the sci- entists are wrapped up head to toe in white coats. No speck of dust that has been impudent enough to settle on one of the wafers escapes their attention. The scientists’ interest in the clean wafers is related to the research and optimization of highly efficient silicon solar cells. Their degree of efficiency is about 20 percent. Particularly RISE thin-layer solar cells (Rear Interdigitated Single Evaporation) are setting very high standards for the processing of the wafers: the slim wafers don’t allow any kind of conventional electronic items, which would conduct electrical current, to be soldered neither at the front nor at the back. This would cause the cells to break. Therefore, in the ISFH test hall vapour is used for the contacts or, using enormous heat, the contacts are burnt into the cells. Having later been assembled in mod- ules, the solar cells end up on the ISFH’s rotating test roofs where they follow the sun’s course. One project has produced solar cells which, with a thickness of 20thousandth parts of a millimetre, are eleven times slimmer than ordinary solar cells. How to adapt the creation of these minute cells to financially profitable, in- dustrial production is one of the key questions. Sunglasses for Windows On the test roofs not only photovoltaics modules but also sun panels are garnering sunbeams. In the solar thermal section, work teams look into the various possible uses of solar heat, how to store it as well as into optimum insulation. The scientists carry out tests with thermic material, i.e. with heat protection glass and weather- proof coatings for sun collectors. They also work with sunglasses for windows. Specific crystals dim out the window panes at a push of a button when an electri- cal current runs through them. Layers are responding to optical stimulation and the window panes adjust accordingly. The Susis, Marta and Uwe At ISFH innovative technology is part of everyday life. In the solar thermal area, for example, Susi I and Susi II seem to be trying to out-beam each other. In close cooperation with the Scientific Services unit, sun panels used in companies are be- ing tested on them as well as on other outside facilities. Unlike the sun, the Susis work independently of the weather and the seasons. Beside Susi I and II, there is Marta, a serviceable lady who is much in demand and indispensable at ISFH. The mechanical testing device gets the upper hand over all sun panels; it breaks them into tiny pieces. Marta simulates storm and hail and her 15 stamps can exert enor- mous pressure on the collectors. Up to one ton of pressure is her potential with Technology on the  Sunny Side of Life at  the Institute for Solar  Energy Research ISFH scientists develop components for photovoltaic and solar thermal use. by Annika Kielmann