How Volcanoes Can Help Thermodynamic Solar
The molten salts are carving out a space of all sorts in the solar concentration (CSP) as an alternative to synthetic oils. Both for thermal storage and as a heat transfer fluid. But there are already those who look at new materials even more efficient. A group of researchers from the University of Barcelona found that volcanic ash could be incredibly useful as a means of energy storage.
The research, published in the Journal of Energy Storage, investigates the potential of this particular material as a cheap substitute of molten salt in thermodynamic solar systems.
Molten salts vs solid ceramic materials
Today compounds such as sodium nitrate and potassium nitrate, with high thermal capacities and which can be heated to temperatures above 400 ºC, offer interesting advantages to concentrated solar. Too bad that the corrosive effect, the eventual solidification and the high production costs do not make these elements the “perfect” ingredient for a rapid spread of the SPC.
This is where solid ceramic materials, already studied and used in large thermal batteries, come into play. On paper, in fact, they offer high accumulation densities while being able to withstand higher temperatures than those managed by solar salts. Thus achieving an increase in the thermal-electrical efficiency of the supply cycles. And since one of the advantages of thermal storage by solid particles is that in some cases it is possible to use local materials (such as igneous, metamorphic or sedimentary rocks), the team of the University of Barcelona has decided to make virtue of necessity.
