ReFlexSPT

Aim
The main objective of the project is to propose failure-free designs of the receiver, the steam generator and the injection in the molten salt tank of current and next generation of Solar Power Towers (SPT), which will also allow these systems to operate flexibly with a greater response speed and reliability, thus making the technology of solar power towers more economically viable, encouraging the penetration of variable renewable energies and providing security to the electricity system.

The viability of solar power tower plants is endangered owing to multiple failures in their high temperature systems, principally the receiver, the steam generator and the molten salt thermal storage tanks. These failures produce unscheduled shutdowns with significant economic losses that increase the financing costs of this technology due to its technological risk. If it were not for these failures, solar power towers would have a great future thanks to their thermal storage, allowing them to obtain great benefits due to their dispatchability and capacity. Furthermore, if their flexibility rises, they could participate in the adjustment market of energy, improving their returns.
In this context, concerning the receiver, the project proposes the use of functional materials that lead to a reduction of corrosion and thermal stresses with higher incident peak powers.
Concerning the steam generator, novel designs will be developed in the project for a highly reliable and quick response steam generator with header and coil configuration, and a safe and highly-flexible steam generator with coil-wound once through configuration featuring a single pass for preheating and evaporation and for superheating and reheating.
Finally, the problem of molten salt leaks at the bottom of the hot tank will be addressed through a characterization and improvement of the coupling between the injection of salts through the sparge ring and the salt level, tanking into account factors like the friction between the tank and its foundation.
Work packages
To achieve the project objectives, and given that these thermo-mechanical problems are not scalable, a set of experiments are schedulled in the molten salt loop, available in the research group’s laboratory at Universidad Carlos III de Madrid, to determine with digital image correlation (DIC), thermography and inverse analysis the experimental variables needed to validate a set of detailed CFD-FEM simulations. Subsequencly, the validated CFD-FEM model are used in the project for the characterization and design of the aforementioned systems on an industrial scale. All these activities are divided into three work packages (WP). The main activities will be principally carried out in WP-E (experimental) and WP-N (numerical), while the WP C are devoted to coordinate the project activities.
Task E.1 Design of the test rigs for the thermo-mechanical validation of the CFD-FEM simulations of the receiver and heat exchanger collectors.
Task E.2 Construction and experimental adjustment of the FGM Receiver Tube and the Header & Tube test rigs for the thermo-mechanical validation of the CFD-FEM simulations.
Task E.3 Experimental measurements of the thermo-mechanical variables in the FGM Receiver Tube test rig and Header & Tube test rig.
Task E.4 Construction and experimental adjustment of the Coil-wound test rig for the thermo-mechanical validation of the CFD-FEM simulations
Task E.5 Experimental measurements of the thermo-mechanical variables in the Coil-wound test rig without evaporation
Task E.6 Experimental measurements of the thermo-mechanical variables in the Coil-wound test rig with evaporation.
Task N.1 Selection of best CFD-FEM and inverse analysis techniques.
Task N.2 Validation of the CFD-FEM simulations and the inverse analysis techniques with experimental and analytical data.
Task N.3 Inverse analysis estimation of temperatures and thermal-stresses from the collected experimental data.
Task N.4 Detailed CFD-FEM simulations of the coupled operation of the solar receiver tubes and collectors.
Task N.5 Detailed CFD-FEM simulations of the Header & Coil and the Coil-wound steam generators.
Task N.6 Detailed CFD-FEM simulations of several thermal storage configurations in nominal, partial load and transient conditions.
Task N.7 Development of new simplified phenomenological models for the solar receiver and the steam generator.
Task N.8 Open software for the estimation of the damage and lifetime of SPT plants in real operative conditions.
Coordination of the all ReFlexSPT project activities
Research group
The personnel of the project comprise researchers of the Energy Systems Engineering (ISE) research group within the Department of Thermal and Fluids Engineering at Universidad Carlos III de Madrid (UC3M). In particular, the following researchers are working in the ReFlexSPT project:
People
The following researchers are working in the SOSreceiver project:
Biography: PhD in Mechanical Engineering and Industrial Organization (2004, Universidad Carlos III de Madrid). and MSc in Industrial Engineering (2000, Universidad Carlos III de Madrid). He has been teaching and researching at the Department of Thermal and Fluids Engineering of UC3M for more than 20 years. His research is currently focused on the Solar Energy in general, including the analysis and thermo-structural modelling of tubular receivers of SPT plants in particular, and the numerical simulation of heat and mass transfer processes of industrial interest. Since 2012 he is associate professor at Carlos III University of Madrid.
Biography: Domingo Santana studied at the Universidad de La Laguna where he obtained a degree in Mathematics in 1994. After finishing his studies, he got a scholarship for the Spanish Government and moved as research assistant to the Universidad de Las Palmas de Gran Canaria where he obtained his Master in Energy and Environmental and PhD in Chemical Engineering. His thesis concerned the modeling and design of fluidized bed aerosol generators. He received the Universidad de Las Palmas de Gran Canaria the outstanding PhD dissertation award in the areas of Architecture and Engineering for theses defended in 1999. Since then, he has been a faculty member at the Universidad Carlos III de Madrid, where in 2017 he was promoted to full professor in the Department of Thermal and Fluid Engineering. His research activities involve the study of the Solid-Gas Systems and Renewable Energies.
Biography: Degree in Mechanical Engineering (University of Castilla-La Mancha), Master in Industrial Engineering (University Carlos III of Madrid), Master in Industrial Mechanics (University Carlos III of Madrid) and PhD in Mechanical Engineering (University Carlos III of Madrid). His main research interests are focused on heat transfer, thermal stress and fatigue-creep analyses of critical components of concentrating solar power plants as steam generators or solar central receivers. Other research interests are exergetic, exergoeconomic and transient analyses of thermal power plants. Pedro Ángel González Gómez is visiting professor at the Department of Thermal and Fluids Engineering in the University Carlos III of Madrid. He has been working in the research and teaching activities in that institution since 2014.
Biography: María de los Reyes Rodríguez studied at the Universidad Carlos III de Madrid where she obtained a degree in Mechanical Engineering in 2010. She got a scholarship for the Universidad Carlos III de Madrid to study a master in Thermal and Fluids Engineerig from 2011 to 2012 and to develop a PhD thesis in Mechanical Engineering from 2012 to 2015. Her thesis entitled «On the design of solar external receivers” concerned the thermal, mechanical and hydrodynamic optimization of solar central receivers. Her research activities involve the study of solar power tower plants. She has developed several numerical models to predict the behavior of the heliostat field and the receiver, stablishing the guidelines to design these plants. Additionally, she has carried out several international stays in CNRS-PROMES, where she worked in the demonstration solar power tower of Themis. Since 2021 she is associate professor at Universidad Carlos III de Madrid.
Biography: Doctorado en Ingeniería Mecánica y de Organización Industrial (Universidad Carlos III de Madrid) Ingeniería Industrial (Universidad Carlos III de Madrid). Her current research topics are Concentrated Solar Power, Thermal Energy storage and Heat Transfer. Brief career history: Universidad Carlos III de Madrid, october 2004 – june 2008, Delft University of Technology, june 2008 – june 2009, Universidad Carlos III de Madrid, june 2009 – present.
Biography: Bachelor degree in Industrial Engineering (2011-2015, University of Cantabria). Master degree in Industrial Engineering (University Carlos III of Madrid, 2015-2017). PhD fellow of the Mechanical Engineering and Industrial Organization program (University Carlos III of Madrid, 2017-2021). Her current research topics are focused on the thermal and mechanical behaviour of external tubular receivers of Solar Power Tower plants. She has been project manager trainee (Airbus Getafe, March-July 2017). Her research activities have started with a PhD fellowship at University Carlos III of Madrid (2017-present).
Biography: Degree in Mechanical Engieneering and Master in Industrial Engieneering in Carlos III University of Madrid. Master in Numerical Simulation in Engineering with ANSYS in Polytechnic University of Madrid. PhD in Mechanical Engineering and Industrial Organization in Carlos III University of Madrid. His current research topics are the Design and optimization of receivers of Solar Tower Power plants. He is currently finishing his Ph.D thesis on these topics through CFD and structural simulations. He was awarded with a PhD fellowship of Predoctoral Investigator (FPI) by the Spanish Ministerio de Economía y Competitividad in the framework of solar research project at Carlos III University of Madrid from April 2017 to September 2021.

Darío Pardillos Pobo
FPU Predoctoral Fellowship
Department of Thermal and Fluids Engineering
Carlos III University of Madrid


Darío Pardillos Pobo
FPU Predoctoral Fellowship
Department of Thermal and Fluids Engineering
Carlos III University of Madrid

Publications
Pérez-Álvarez, R., Marugán-Cruz, C., Santana, D., Acosta-Iborra, A. Influence of eccentricity on the thermomechanical performance of a bayonet tube of a central solar receiver, Applied Thermal Engineering, 2023, 223, 119988.
M. Laporte-Azcué, A. Acosta-Iborra, T.P. Otanicar, D. Santana, 2023, Real-time estimation of the transient thermomechanical behaviour of solar central receivers. Thermal Science and Engineering Progress 41, 101834.
R. Pérez-Álvarez, A. Montoya, J. López-Puente, D. Santana, 2023, Solar power tower plants with Bimetallic receiver tubes: A thermomechanical study of two- and three-layer composite tubes configurations. energy 12917.
R. Pérez-Álvarez, E. Cano-Pleite, F. Hernández-Jiménez, A. Acosta-Iborra, 2024, Thermomechanical behavior of mechanical attachments in solar power tower receivers under preheating conditions: A numerical study. Applied Thermal Engineering 236, 121444.
Funding Entities
Grant PID2021-122895OB-I00 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”.

