DOE OSTI2011
This report contains the results of work performed in on Phase 1 and Phase 2 related to the Brayton Solar Power Conversion System project. The SolarCAT (Solar Compressed Air Turbine) is dish-engine module with compressed air energy storage. It generates 200-kWe peak power, employing a 320 sq. meter dish. Designed for multi-MW arrays, the power plant provides utility load-profile shaping as well as efficient solar power conversion. At the discretion of the utility operator, the gas turbine also operates on a wide range of fuels (bio and fossil) to supplement solar power or provide non-solar operation. A brief description of the principal subassemblies follows: • The “engine” is a compact turbo-alternator operating with only air serving as the working fluid, the lubricant, and the coolant. The turbo-alternator has been designed to be maintenance-free for the 20-year (60,000 hour) life. • The solar receiver is a tubular design incorporating mature heat exchanger design practices. ORNL has been instrumental in evaluating materials for this application. • The tracking solar concentrator (Dish) was developed and installed at Southwest Solar Technologies, by private funding. The unit constructed for Phase 2 has a collection area of approximately 320 sq meters. The critical subassemblies of the system have been fabricated and tested in Phase 2 of this program. Each subsystem was purpose-built for this new power generation system. This included a special turbo-alternator system built with air bearings, a very compact recuperator, a hybrid combustor, and a solar receiver fully integrated for installation on the SST dish. The receiver was tested alone on the dish. The extensive testing of the turbomachinery, dish and receiver conducted on this program has overcome common development issues. Furthermore, the team has worked exceptionally hard to prove the performance and cost basis of the system. Reliable subsystems have been checked-out and are ready to be move into the complete engine-dish module in Phase 3. In parallel, several economically-driven component upgrades have been identified which improve efficiency and lower cost. The project was terminated prior at the end of Phase 2, to installing the special purpose recuperated turbo-alternator on the dish.