Engineering news
Immediate, on-demand access is an ongoing issue for renewable energy, but researchers from Chalmers University of Technology in Sweden hope their system could successfully capture the Sun’s heat for cold Scandinavian winters – and offer commercial energy storage around the world.
The team previously presented a molecule made of carbon, hydrogen and nitrogen, which transforms into an energy-rich isomer when hit by sunlight. The liquid substance is stored in a pipe in a concave solar reflector, which tracks the Sun’s progress across the sky and focuses the rays on to the pipe. The liquid is warmed, transforming into the isomer, before it is stored at room temperature.
Since announcing the energy-capturing molecule, the team has further developed the technology.
“The energy in this isomer can now be stored for up to 18 years,” said chemist and chemical engineer Professor Kasper Moth-Poulsen. “And when we come to extract the energy and use it, we get a warmth increase which is greater than we dared hope for.”
He added: “We have made many crucial advances recently, and today we have an emissions-free energy system which works all year around.”
The group developed a catalyst for controlling the release of the stored energy. The isomer liquid flows through the catalyst, causing a reaction that warms it by 63ºC. The liquid also returns to its original form, making it available for reuse.
A redesign of the molecule to allow the theoretical 18-year storage limit was “crucial”, the team said, as the project’s focus is primarily chemical energy storage. The researchers also found a way of removing toluene, a potentially dangerous flammable chemical, from the stored liquid.
The result, the team said, is a completely emission-free, “circular” concept capable of applications including domestic heating. Moth-Poulsen said there is nonetheless “a lot left to do,” adding: “We have just got the system to work. Now we need to ensure everything is optimally designed.”
The group believes that a temperature increase of 110ºC will be possible and that it could be in commercial use within 10 years.
The research was published in Energy & Environmental Science.
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