Storage and Conversion of concentrated thermal solar energy (ALCONNES)

Participants: IMDEA Energia (Coordinator), University J. Carlos I, ICP-CSIC and CIEMAT. SENER (Spanish engineering company) and ABENGOA Hidrógeno (company subsidiary of the ABENGOA group) act as industrial companies with active collaboration and interest in the possible exploitation of the project results.
Contacts: Manuel Romero,; Alfonso Vidal,
Funding: 2,017 M€; Community of Madrid.
Duration: October 1, 2014 – October 31, 2017

Background: The ALCONNES project is a very ambitious initiative that involves R&D public institutions, IMDEA Energia (Coordinator), University J. Carlos I, ICP-CSIC and CIEMAT. The program AlCConES (the acronym in Spanish stands for Storage and Conversion of Concentrated Solar Power) focuses its R&D objectives onto the heart of CSP systems, that is the loop involving conversion from high flux solar to thermal energy, including the storage system needed to optimized dispatch on demand for further use of energy in the production of electricity, solar fuels or chemicals.

Objectives: Within objective 2, CIEMAT is exploring new solar receivers and reactors for the efficient operation at high temperatures and with high penetration of photons for high incident flux.   Furthermore, within objective 3, “Develop new storage and dispatching thermal energy systems”. CIEMAT will be focused on new perovskite materials as candidates for thermochemical cycles.

Achievements in 2015:
Some work in 2015 was focused to study the technical feasibility of chemical reactors concepts based on direct heated fluidised bed reactors. A fluidised bed reactor located in a solar dish has been operated. The fluidised reactor is a refractory lined steel cavity of about 200 mm diameter aperture. Commercial Ni ferrite were selected as as a model material for solar experiments at a fluidised bed reactor. The granular material or bed is introduced at the reactor as a power and is moving by using N2 as fluidised gas.

Test campaign was made in a continuous mode, filling the reactor with a controlled amount of material and N2 is flowed through the bed to ensure an acceptable moving bed height and residence time. First results were focused to determine the best operating conditions: minimum gas velocity, height of the bed, etc
Within objective 3, our research efforts were directed towards preparation and synthesis of the perovskites materials in the laboratory, such as LaxSr1-xMnyAl1-yO3 and LaxSr1-xFeyAl1-yO3, and testing, improving the kinetics and reducing the working temperatures.

Fig. 1. TGA experiments showing weight losses of studied materials

Comparability between the different materials were established by TGA experiments the under various reaction conditions. TGA experiments showed different weight losses between different samples (Fig. 1). First hydrolysis test carried out with this material indicated that the recovery of O2 is not complete within the operation conditions.