Astep Project

ASTEP_Selection and Definition of Materials and Manufacturing

The focus at this point is on the choice of Phase Change Materials (PCM) materials and manufacturing methods for PCM-based thermal energy storage units characterized by the high rate of charging and regulated rate of discharging and large storage capacity. At least two test units for composite PCMs storage systems shall be implemented and validated according to the criteria given by the end-users.

PCMs will be selected considering the appointed melting range (exceeding 175 °C or 230 °C), possibly from multi-component mixtures of salts with high latent heat and possibly low chemical affinity to aluminium inserts.

To use solar power in the processes in the night, when the Sun does not shine, the energy has to be stored somehow. For effective energy storage the PCMs have been chosen, and to be more precise, solar salts.


What are PCMs?

‘Phase Change Materials’ are a wide group of materials, which can store the latent heat – the heat needed to overcome a phase transition, like melting (the most common) or evaporating. They are characterized by the high enthalpy of phase transition and by relatively high heat capacity.  The narrow phase change temperature range is also required. That is why, depending on the application temperature, different materials can be used as PCM. The classification of PCM is connected to their chemical nature. The family of PCMs can be divided into organic materials (polymers, paraffin waxes, fatty acids), inorganic (salt hydrates, metal alloys), and eutectic (often mixes of organic and inorganic substances).

The choice of PCM tailored for the application is mainly connected with the temperature of phase transition.

Considering the case studies examined in the ASTEP project, for Arcelor Mittal a special salt mixture was chosen.

We hope our choices will provide great service not only to our partner but to us all as well.

Author: M.Sc. Eng. Natalia Raźny (PWR)