Thermal Energy Storage for Direct Steam Generation

Abstract

Parabolic trough power plants with direct steam generation are a promising option for future cost reduction in comparison to the SEGS type technology. These new solar thermal power plants require innovative storage concepts, where the two phase heat transfer fluid poses a major challenge. A three-part storage system is proposed where a phase change material (PCM) storage will be deployed for the two-phase evaporation, while concrete storage will be used for storing sensible heat, i.e. for preheating of water and superheating of steam. A storage system with a total storage capacity of approx. 1 MWh is described, combining a PCM module and a concrete module. The storage modules have been constructed for testing in a DSG-test facility specially erected at a conventional power plant of Endesa in Carboneras (Spain). Commissioning of the storage system started in May 2010; testing under real steam conditions around 100 bar will begin in August 2010.