Energy Storage

Energy storage and the effect of nanoparticles in molten salts heat capacity

Description

Energy storage is the key point for the consolidation of renewable energies. These energies are intermittent so it is essential to develop safety and efficient storage systems. As a matter of fact, solar radiation reaching atmosphere is by far higher than the annual Earth’s energy demand. In this regard, for example thermal energy collected by thermal collectors should be storage efficiently by means of thermal storage materials (TSM). There are three types of direct thermal energy storage: sensible, latent and chemical heat. The former is based on the temperature increase/decrease of a material to storage heat. Conversely, latent heat storage is associated to a phase change of the material taking advantage of the change phase enthalpies to storage the energy. Finally, chemical storage is done reversible chemical reactions where the thermal energy is storage on the products of endothermal reactions, reverting the situation through an exothermal process.

Concentrate Solar Power Plants commonly use molten salts (a mixture of sodium and potassium nitrate) as thermal storage material that allow to operate around 550°C. These plants use solar radiation concentration systems like mirrors and lens. The concentrated light is converted in heat by means of receptors and transferred to energy storage systems. This thermal energy runs turbines connected to electrical energy generator that finally generated electricity.

Thermal stability is one of the main advantages of solar salts allowing a higher temperature of operation. However, they also present drawbacks (e.g., highly corrosive and low thermal capacity value). In this regard, research on this field tries to increase thermal capacity by introducing nanoparticles. In our group of research, we are performing computational simulations to understand the mechanisms behind the increase of thermal capacity observed when nanoparticles are introduced in the system and why this effect is missed at a certain concentration of nanoparticles.

Collaborations

Dra. Anna Inés Fernández and Dra. Camila Barreneche (DIOPMA Group, Dept. Materials Science and Physical Chemistry, UB, Barcelona, Spain)