By Dr. Reiner Buck, DLR, Germany.
2. Technical requirements for central receiver systems: design, materials, components and HTF (Molten salt, air?)
Solar tower systems are nowadays getting more important, due to expected future cost reductions with this technology. Solar tower plants and their components are described using state-of-the-art molten salt systems as reference. Performance and cost characteristics of the main subsystems are outlined, like heliostat field, receiver, storage and power block. Further development work aims at increasing process temperatures and system efficiency, and to reduce investment cost. New technological approaches, e.g. using new heat transfer and storage media, are presented and discussed.
3. Challenges for heliostat development
The concentrator system of a solar tower plant is composed of thousands of tracked mirrors, so-called heliostats. The heliostat field contributes about 40% of the total investment cost of a solar tower plant. Main challenges are the required high optical accuracy while reducing material use and cost. The current heliostat technology is described, including components like mirrors and drives for the two-axis tracking. The influence of optical and tracking quality on field performance and cost is discussed. In addition, a new heliostat concept developed in collaboration with Moroccan partners will be presented.
Dr. Reiner Buck is a Mechanical Engineer and received his PhD in 2000 from the University of Stuttgart on the topic of “Mass Flow Instabilities in Volumetric Receiver-Reactors”. He has worked since 1986 on various solar technologies. Since 2011 he is leading the department “Point Focusing Systems” within the DLR Institute of Solar Research. With about 25 staff members, the department is concentrating on the development of solar tower systems. The main expertise of Reiner Buck is on receivers, heliostats and simulation tools for solar tower system. He developed several simulation tools for solar power systems (ray-tracing tools for heliostat fields, thermal performance analysis for various types of receivers), and has experience in developing and testing of receivers for different heat transfer media like molten salt, air and solid particles. He is also working on the development of innovative concentrator systems. He also led and participated in numerous national and international collaboration projects on CSP. He co-authored more than 160 research publications and several book chapters, and has co-chaired international conferences. He holds a number of patents and has supervised several university and PhD students.