With the help of the artificial sun, the researchers want to create hydrogen without the need for electrolysis. The lamps heat metal to 800 degrees. It is then sprayed with water vapour. The metal reacts with the oxygen and hydrogen is left over. If the metal is reheated, the oxygen separates. The reactor used for this is shown in the image on the right.© Anna Durst, BINE Informationsdienst

Synlight, the world's largest high-flux solar simulator 27.03.2017

Jointly active for the solar research (from left): Axel Fuchs, Mayor of the Town of Jülich, Professor Bernhard Hoffschmidt, Head of the DLR Institute for Solar Research, Dr Georg Menzen, Head of the Department for Energy Research at the German Federal Ministry for Economic Affairs and Energy, Johannes Remmel, NRW Environment Minister, Professor Karsten Lemmer, DLR Executive Board Member responsible for Energy and Transportation, Dr Kai Wieghardt, Synlight Project Manager and Carlo Aretz, Managing Director of Jülich Technology Center.© DLR (CC-BY 3.0)

The sun shines with the click of a mouseSynlight is the name of the world's largest artificial sun, which is situated in Jülich near Aachen. Its bundled light is 10,000 times stronger than the sun. With this energy, researchers want to test solar thermal components in order to produce hydrogen directly – without having to use electrolysis. Last week, the research facility was officially inaugurated.

The radiation conditions outdoors are never consistent, which is what researchers need in order to make their experiments reproducible. However, in future the researchers from the German Aerospace Center (DLR) will be able to experiment with the artificial, electrically operated sun – regardless of the weather conditions and seasons. The artificial sun ensures constant and pre-defined radiation conditions.

The indirect irradiance from the walls is so intense within the Synlight facility that a human being could only withstand it for one second. Therefore, the system cannot be started unless all safety doors are closed. It is completely sealed during operation. If all reflectors are aligned on a single point, up to 3,500 degrees Celsius can be achieved. Each reflector has a one-metre diameter. The 149 xenon short-arc lamps are mounted on a 15 metre-high steel structure arranged in the form of a parabolic mirror. Each reflector can be variably adjusted so that the light is focussed either on a point or is distributed over a larger area. Each xenon spotlight has the light output of a large cinema projector. "These lamps are the most similar to the sun," says Synlight Project Manager Dr Kai Wieghardt from the DLR.

The research facility was officially inaugurated last Thursday on 23 March 2017. At the start, 30 of the 149 high-power spotlights focussed their light on a two-centimetre-thick aluminium plate. Within just two minutes, the

At the official inauguration, 30 of the 149 high-power spotlights focussed their light on a two-centimetre-thick aluminium plate. Within just two minutes, the bundled electrical light melted the plate and burned a hole in the metal.© Anna Durst, BINE Informationsdienst

Each individual reflector has a one-metre diameter.© Anna Durst, BINE Informationsdienst

The research facility was officially inaugurated last Thursday on 23 March 2017. At the start, 30 of the 149 high-power spotlights focussed their light on a two-centimetre-thick aluminium plate. Within just two minutes, the bundled light melted the plate and burned a hole in the metal.

Largest solar simulator can be utilised for diverse purposesThe new Synlight research facility is the largest artificial sun in the world. It provides ideal possibilities for testing components and developing new or improved processes for solar thermal power plants, solar chemistry and space travel. Since the spectrum of UV radiation is similar to that of the sun, the ageing of materials can also be tested in an accelerated manner.

The high-efficiency radiator was built in a specially constructed building belonging to the Jülich Technology Centre, within sight of the Jülich solar tower. Construction already began in 2015. All the spotlights can be focussed on three test chambers. Two of these three chambers are specially tailored to meet the requirements for solar-chemical process development. These will provide direct access to exhaust gas scrubbers and neutralisers – a necessary prerequisite for testing processes for solar fuels.

Producing hydrogen directlyHydrogen only occurs on the earth as a chemical compound. With the artificial sun, it can now be split off in a direct, chemical process. Hydrogen is usually produced indirectly by means of electrolysis, which requires, for example, the conversion of solar or wind energy into electricity. In the Synlight facility, the lamps heat metal to 800 degrees centigrade. This is then sprayed with water vapour; it reacts with the oxygen and hydrogen is left over. If the metal is reheated, the oxygen separates. The researchers want to use laboratory tests to determine which metal is most suitable for producing hydrogen.

Ten times larger than on a laboratory scaleThe DLR scientists succeeded years ago in producing hydrogen – but only on a laboratory scale with an output of about 20 kilowatts. The scale has to be significantly larger for industry. With around 350 kilowatts, Synlight delivers ten times the performance of previous laboratory systems. Project leader Wieghardt adds: "Size-wise, the new artificial sun lies between laboratory-scale facilities and larger-scale facilities such as the solar tower here at Jülich."

The solar simulator consumes as much electricity in four hours as a four-person household does in a year. Although that may sound a lot, the research facility is intended to improve the efficiency of solar thermal power plants. If the researchers manage to increase the efficiency of a solar power plant by just one per cent, this energy expenditure will be worthwhile.

The German federal state of North Rhine-Westphalia has spent 2.4 million euros in helping to fund the research facility and the German Federal Ministry for Economic Affairs and Energy has spent 1.1 million euros on the project.

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