At DLR's site in Jülich, some 60 km west of Cologne, the DLR Institute of Solar Research has been operating the solar thermal test facility Jülich since 2011. Covering an area of about ten hectares, there are more than 2,000 movable mirrors (heliostats), directing the incoming sunrays to the top of the 60 m high solar tower. There, the focused sunlight is collected by a 22 m² solar receiver and converted into heat. In the process the air reaches a temperature of up to 700 °C and generates water vapor, which drives a steam turbine. A connected generator converts the mechanical rotational energy provided by the turbine into electrical energy.
The nominal electrical capacity of the system is 1.5 MW. The electricity is fed into the public grid at medium voltage level. A high-temperature heat storage is used to decouple the fluctuating solar radiation supply from the energy supply and thus enables a clearly smoothed course of the feed-in performance.
At mid level, the solar tower is equipped with a research level giving room for changing experiments under concentrated solar radiation.
Funded by the federal government and the state of North Rhine-Westphalia, DLR expanded the Jülich site by the end of 2015 with additional test facilities. Soon, it became clear, that one research level in the existing solar tower was not sufficient to meet the demand from research and industry. DLR started in 2019 the construction of a second tower next to the existing solar tower. Its three irradiation planes can be used in parallel and in addition the existing research level of the first tower. The new multifocus tower allows more experiments and will speed up project development times. The building works shall be completed in spring 2020.
Solar researchers at DLR and their cooperation partners are testing new components and processes in various projects to make solar power plants more efficient. The focus is on mirror systems for directing and concentrating solar radiation, solar absorber and energy storage systems as well as on theoretical and computer-assisted analyzes and developments in the field of fluid mechanics and heat transfer. Depending on the development status and goal, individual components, functional groups or even a complete solar power plant system can be tested, evaluated and optimized.
In addition, the production processes of solar fuels and the use of high-temperature solar heat for industrial processes are tested at the Jülich Solar Tower.