A technology developed at CERN captures the sun's energy

A civil-engineering company has recently started using thermal solar panels based on ultra-high vacuum technology developed at CERN. By efficiently preventing heat loss, the technology allows water to be heated to several hundred degrees, even in a temperate climate.


The field of solar panels using technology developed at CERN.

On Tuesday 15 June the Geneva branch of the civil-engineering company Colas opened a new solar power plant based on ultra-high vacuum technology developed at CERN. Measuring a total of 80 square metres, the environmentally friendly "solar field" heats close to 80,000 litres of bitumen to 180 degrees. "To be able to reach such a high temperature, I drew on the ultra-high vacuum technologies I learned about at CERN", explains Cristoforo Benvenuti, who invented the panels.

The ultra-high vacuum is what makes these solar panels so innovative. "It's very attractive because it minimises heat loss", continues Benvenuti. "The temperature of a solar panel works like a bank account. When you're on a low income, one way of building up your account is to reduce your expenditure. It's the same thing with the panels: to increase the temperature you have to minimise heat loss. And vacuum is the best heat insulation technique Nature has to offer." Getter pumps are used to create the ultra-high vacuum. These pumps work a bit like chemical sponges, trapping any air molecules that are unlucky enough to get near them.

The second important ingredient, given the weather conditions in Geneva, is diffuse or indirect light, which is recovered using a reflective device consisting of two cylindrical mirrors (see photo). "The panels create steam, whether or not the sun is shining! This is very useful since, in Central Europe, diffuse light can represent more than 50% of the total solar energy available".

"All this is another example of how the technologies developed at CERN for fundamental research can lead to the development of innovative products", says Hartmut Hillemanns, a member of the Knowledge and Technology Transfer Group. Even if it typically takes 5 to 10 years to market them, the time and manpower needed to bring prototype technologies to the stage where they can be commercialised are a good investment. The resulting products help to underline the importance and usefulness of particle physics for society in general." 

Cristoforo Benvenuti, seen with an example oh his invention: the ultra-high vacuum thermal solar panel.

The green technology used in the solar panels may well be of interest to other industries in the construction, chemical and food sectors, for example. In any case, there are already plans to extend it to the entire Colas factory in Vernier (Geneva), or even to all Colas plants in Switzerland. However, it is of less interest to individual home-owners: "The solar panels produce hot water but at very high temperatures of up to 300 degrees", explains Benvenuti. "Simpler and probably less costly panels are more suited to domestic use".

Technological developments are springboards for innovation as they benefit research as well as industry, as Benvenuti confirms: "At first, I drew inspiration from CERN's ultra-high vacuum technologies, then that got me interested in Getter pumps. When I realised their advantages, I put them forward for use in the LEP and later the LHC, and they are widely used in the LHC today. It's therefore fair to talk of a two-way exchange that benefits both the solar industry and CERN!" 

Watch the video on the solar panels:

by Alizée Dauvergne