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25 August 2016

ADEM Society

The ADEM Innovation Lab is the working home of several dozen researchers. But who are they, and what exactly do they do here? In each issue, the column ‘ADEM Society’ introduces two of these researchers. This time Claire Ferchaud and Emanuela Negro bring us up to date on their work, its wider relevance and its commercial potential.

When it comes to the energy transition, seasonal heat storage is a key topic for both science and society. For Claire Ferchaud, the core issue is the seasonal storage of solar energy. That is crucial because it paves the way for smaller domestic systems, rather than just the large centralised ones currently available. In her research, therefore, Ferchaud has been concentrating upon thermochemical heat storage. “For my PhD,” she explains, “I’ve been studying this breakthrough technology as it can be applied in northern Europe. My work is focused on improving the materials used and the system design. The breakthrough lies not only in the fact that it enables storage at the level of individual households for the first time, but also that this can be done for an unprecedented low price.”

Summer, autumn and winter

The thermochemical materials at the centre of Ferchaud’s research are salt hydrates. The basic principle? Charge in the summer, store in the autumn and discharge in the winter. How? “The salts take up water in their crystal lattice,” says Ferchaud. “If you bring this kind of salt into contact with water vapour, a number of water molecules attach themselves to the salt molecule. The resulting reaction produces a lot of heat per molecule, and is entirely reversible. In the summer, then, you can use the heat from the solar boiler to separate the water molecules from the salt. You then store them separately. In the winter you reverse the process, with the water-salt contact generating heat.”

Additional research

Because this is a breakthrough technology, Ferchaud knew from the outset that her fundamental research might produce a negative result. “Unfortunately, the process we devised for sulphate and chloride-based salt hydrates couldn’t be validated successfully. That’s a shame, but on the other hand it does show clearly that this type of material is unsuitable. Which means that we can turn our attention to other materials. That’s essential if we are going to achieve a breakthrough. Several universities have now started new research. Right now I’m busy completing my PhD and still working in this domain. I remain fully dedicated to the seasonal thermochemical storage of solar energy!”

Fuel cells

It was a passion for fuel cells that inspired the ADEM research project initiated by Emanuela Negro at the end of 2010. Specifically, cells based upon a polymer electrolyte membrane (PEM). Negro: “This technology is viewed as a very promising alternative to the internal combustion engine in mobility applications. That’s because of its higher efficiency and lower carbon-dioxide emissions. I’ve been investigating so-called carbon nanostructures [also known as carbon nanonetworks, or CNNs – ed.] and their use as catalyst carriers in fuel cells. One of the major challenges here is making them more resistant to corrosion, as that causes degradation and ultimately affects their performance.”

Graphene

Because they are less prone to corrosion than other types, Negro has been focusing upon graphene-based CNNs. “We’ve developed a new material which is now being produced on a small scale by Carbon X, a spin-off of Delft University of Technology. They’ve investigated several kinds of material and recognise the potential of CNNs with graphene.”

Despite the huge success of Negro’s research so far, she admits that there is a long way to go before her material can go into mass production. “The challenge is upscaling. If Carbon X were able make the material in sizes large enough, in terms of surface area, production could start tomorrow. But that’s not the case, so further research is needed.”

3D structure

Despite this, Negro looks back with satisfaction on her work so far. “After all, we’ve proven that this innovative material has a future. Its great advantage is that, once it’s being produced on a large enough scale, it has the potential to be much cheaper than competing products. Also, it has a 3D structure and that makes it significantly safer.”