Energy storage system temperature requirements

High temperature thermal energy storage offers a huge energy saving potential in industrial applications such as solar energy, automotive, heating and cooling, and industrial waste heat recovery. However, certain requirements need to be faced in order to ensure an optimal performance, and to further achieve widespread deployment.

Chemical requirements are very similar for sensible and latent heat storage materials ( Table 2 ). Candidate materials should have long-term chemical stability, no chemical decomposition, should be compatible with the container materials and the HTF, non-toxic and non-flammable, and they should present no phase segregation.

Among the different energy storage technologies, thermal energy storage (TES) is an effective technique that has become a key factor on improving the efficiency of different energy systems due to the versatility in correcting the mismatch between the energy demand and supply, and by allowing the development and implementation of renewable energies.

High-temperature storage offers similar benefits to low-temperature storage (e.g. providing flexibility and lowering costs). However, high-temperature storage is especially useful for smart electrification of heating and cooling in industry, given that many industrial processes either require high temperatures or produce high-temperature heat.

The last thermal requirement regarding the use of the latent phase is the utilization of a TES material with congruent melting in order to ensure that it completely changes of phase and therefore, both solid and liquid phases remain homogeneous. These three parameters can be evaluated with commercial devices.

Thermo-physical properties of ferrous slag,,, indicate very appropriate values for the use of this material in sensible thermal energy storage up to temperatures of 1200 °C. Finally, some authors proposed mixtures of wastes and TES materials.