The Dual Medium Storage Tank at the IEA/SSPS Project in Almeria (Spain); Part I: Experimental Validation of the Thermodynamic Design Model

Abstract

Efficient and reliable thermal storage is an important requirement for substituting conventional power systems with solar thermal facilities. Storage will synchronize the intermittent supply of solar radiation with the usually constant demand of technical thermal processes. The distributed collector system of the IEA/SSPS Project in Almeri´a (Spain) uses two different storage systems for the 100 to 295°C temperature range: a single thermocline vessel and a dual medium storage tank (DMST). In the first tank, thermal oil is used as the energy carrier as well as for energy storage; in the dual medium tank, the storage medium is cast iron, and the oil acts primarily as a heat transfer fluid. At the SSPS, this concept’s potential for future process heat applications has been assessed. Performance and operational restrictions of the DMST were systematically studied over a wide range of temperatures, and an existing simulation model was verified and adapted at the same time. The thermodynamic model of the DMST is presented and compared with the first results of the 1985 test program.