Storing Energy in Volcanic Rock and Scrap Metal

At Caldera we are passionate about delivering a solution to decarbonise industrial heat, which is responsible for 20% of the world’s carbon footprint. Caldera’s ‘heat cells’ enable industrial heat to be produced on demand from renewable power. They use three interlocking innovations: a composite core material; steam for extracting energy; and vacuum insulation. This post looks at why we selected the material used for the core of the heat cell and its advantages relative to other materials.

We use a proprietary composite of volcanic rock in an aluminium matrix – think high-tech concrete. This rock/aluminium core has a high thermal storage capacity, comparable with rock, sand or concrete which are used in several competing technologies. Where the Caldera solution differs is that, thanks to the aluminium, the core is over fifty times more thermally conductive – it transfers heat more easily than these competing materials.

A second, and equally important, property is that the aluminium softens in the 200-500 °C operating range, making the composite material ‘compliant’. This means that the material does not crack when thermally stressed, which is a significant problem with anything large and solid like concrete structures. Together these properties mean we can charge and discharge the thermal store very rapidly, without having issues with thermal shock or other degradation of the storage medium. It also means that the store can be cycled indefinitely with no degradation to capacity.

We also chose rock and recycled aluminium for their affordability, availability, and sustainability. Volcanic rock is an abundant and low-cost material, easily obtained in the correct sizes for our composite core. Aluminium is the most abundant metal in the Earth’s crust. Furthermore, we don’t require energy intensive primary aluminium from smelting, but work with recycled low-grade scrap aluminium, generally only suitable for castings. Aluminium requires 95% less energy to recycle than to make from new, so there is a big environmental benefit in using scrap.

We hope this post has given some insight into why Caldera’s research led us to create this unique and patented material. In future post we’ll look at the other key technologies in a heat cell.

Enjoyed this post and interested in supporting our mission to decarbonize heat? You have an opportunity to invest in us via Crowdcube. Here's the link: https://link.caldera.co.uk/ws2uDv

Risk warning: Don’t invest unless you’re prepared to lose all the money you invest. This is a high-risk investment.

#innovation #sustainability #sustainable #startups #environmental #socialentrepreneurship #industrialengineering #industrial #factory #materials