A R+D activity integrated in Plataforma Solar de Almeria

Head:  Esther Rojas

The main objective of the Thermal Storage and Solar Fuels Unit (ATYCOS) is to store, directly or indirectly, concentrating solar thermal energy. Directly thanks to designing optimized thermal energy storage systems and indirectly thanks to the so called solar fuels (Methane reforming) and by producing Hydrogen with thermochemical processes.

Thermocline tank simulation by
numerical and analytical models

In the area of Thermal Storage, ATYCOS focusses on the development, optimization and integration of thermal energy storage systems (TESS), taking into account the specific technological features of the solar thermal power plant involved.

Strategies and optimization of TESS
integration in CSP plants

Our great know-how, both in (sensible and latent) storage prototypes testing and in multi-physics modelling (by own or commercial programs), qualify us to design and optimize TESS for working temperatures between 140ºC and 800ºC. In this sense, we follow a holistic approach where the TESS integration in the Concentrating Solar Power Plant plays a critical role.

The activities of the Thermal Storage Group deal with all aspects involved in the development, verification and optimization of efficient TESS:

  • Proposing new storage media and characterizing some of their mechanical, chemical and thermophysical properties1.
  • Testing components for molten salt loops (valves, pressure gauges, vertical pumps, heat tracing, etc.).
  • Designing new heat storage concepts with known storage media.
  • Testing novel modules for energy storage, both sensible and latent, even in real solar conditions.
  • Modelling the behaviour of TESS, with own and commercial programs.
  • Studying the integration of TESS in the CSP and its feasibility from a global point of view.
  • Optimizing the operation strategies of TESS in order to obtain a maximum advantage of the stored energy.

1Thanks to Ciemat’s laboratories and testing facilities

Due to the growing interest of Hydrogen as an energy vector for the transport sector and the undisputed attraction of its clean production, the Solar Fuels Group of ATYCOS pays special attention to Hydrogen production by concentrating solar thermal technologies at high temperatures. Another objective of ATYCOS is the application of concentrating solar thermal systems to thermochemical processes in industry, bearing in mind that such processes tend to be large thermal energy consumers.

The activities of ATYCOS in relation to Hydrogen are specified in two main research fields:

  • Development of processes and technologies for the decarbonisation of fossil fuels and their valorisation by solar gasification, paying special attention to low-quality carbonaceous materials.
  • Demonstration, on a pre-commercial scale, of the technological and economic feasibility of water dissociation for Hydrogen production through thermochemical cycles driven by concentrated solar thermal energy.

For developing these research fields we,

  • Perform studies of the integration of thermochemical industrial processes in central receiver plants.
  • Analyse the chemical equilibrium, thermodynamic and kinetic performance of innovative thermochemical processes, based on new materials.
  • Simulate, design and operate, both in laboratory conditons and in real solar conditions, chemical reactors with different configurations: volumetric, cavity receivers, fluidized beds, etc.

Simulated thermal map of a tubular reactor under concentrated solar radiation

From the experience gained with thermochemical reactors for Hydrogen production, a new line of R&D&I arose, with the objective of producing Oxygen from Lunar regolith. The specific boundary conditions on the Moon impose a new design for the concentrating mirror that has to be microlight.


Through its experts, the Thermal Storage and Solar Fuels Unit participates actively in several scientific networks (Energy Storage JP of EERA, Task II and III of SolarPACES IA of the IEA, Spanish association for Hydrogen –AeH2-) and national (AENOR-GT3) and international (IEC- CTN 206/SC 117/GT 03 and ASME-PCT52) standardization committees.

Since the very beginning, the Unit has worked closely with colleagues from various universities, industrial partners and technological centres of several Autonomous Communities of Spain, through specific collaboration agreements.