CASCADING THERMAL ENERGY STORAGE (TES)
The thermal energy storage of the HYBRIDplus solution propose a cascade configuration using Phase Change Materials (PCM) enhanced with metal wools that can reproduce the effect of a thermocline. The heat is stored as latent heat (phase change) and sensible heat (temperature change), greatly increasing the energy density of the storage, and thus allowing a reduction in the total tank volume (and cost). The cascade concept reproduces the charge and discharge curve of a sensible media, with minimum pitch point and maximum round trip efficiency, but with the higher energy density of the PCM.
With this configuration, the solar salts typically used in CSP both as heat transfer fluid (HTF) and as storage material, will be only used as HTF, reducing the total amount of solar salts required for the plant. With this cascade configuration, solar salts can be use at the highest temperature to feed the CO2 power cycle avoiding thermal degradation at maximum temperature due to the low residence time. This configuration enables the use of the advanced supercritical CO2 power cycles in the high efficient dispatchable CSP plants.