The Riyadh Techno Valley Solar Tower, an innovative type of concentrator solar power plant, is being developed by King Saud University (KSU) and Georgia Tech (GT). The facility is being constructed at the Riyadh Techno Valley development near the KSU campus and will store thermal energy collected from the sun in solid particles, which can be heated to higher temperatures than is currently possible using molten salts. The particles must be well insulated to stop energy loss to the environment. Hence, GT and KSU have incorporated an insulated storage bin into the plant design.
The bin will be constructed in several layers: an inner layer of firebrick, which can endure direct exposure to the heated particles; a specially prepared refractory insulating concrete, which maintains good insulating value at high temperatures; and a conventional structural concrete shell surrounding the entire bin. This paper presents a thermal analysis of this storage device and discusses structural analyses. Simplified analytical solutions are compared with the finite element results from a 3D ANSYS model of the entire bin. A temperature distribution is obtained, and heat loss through the bin is also evaluated.
Modeling of rebar and concrete cracking are described, and methods of reducing stress on the outer concrete shell are considered. Structural support for an access tunnel into the bin is also explored. The current tunnel design involves a material with a relatively high thermal conductivity, necessitating modifications to the bin. Finally, material selection is considered, particularly with regard to the insulating concrete layer. Limitations on the use of Portland cement based insulating concretes are discussed, and alternative base materials are evaluated.