

Furthermore, the system was previously reliant on the liquid being partly composed of the flammable chemical toluene. But now the researchers have found a way to remove the potentially dangerous toluene and instead use just the energy storing molecule.



Taken together, the advances mean that the energy system MOST now works in a circular manner. First, the liquid captures energy from sunlight, in a solar thermal collector on the roof of a building. Then it is stored at room temperature, leading to minimal energy losses. When the energy is needed, it can be drawn through the catalyst so that the liquid heats up. It is envisioned that this warmth can then be utilised in, for example, domestic heating systems, after which the liquid can be sent back up to the roof to collect more energy – all completely free of emissions, and without damaging the molecule.



“We have made many crucial advances recently, and today we have an emissions-free energy system which works all year around,” says Kasper Moth-Poulsen.



The solar thermal collector is a concave reflector with a pipe in the centre. It tracks the sun’s path across the sky and works in the same way as a satellite dish, focusing the sun’s rays to a point where the liquid leads through the pipe. It is even possible to add on an additional pipe with normal water to combine the system with conventional water heating.



The next steps for the researchers are to combine everything together into a coherent system.

“There is a lot left to do. We have just got the system to work. Now we need to ensure everything is optimally designed,” says Kasper Moth-Poulsen.



The group is satisfied with the storage capabilities, but more energy could be extracted, Kasper believes. He hopes that the research group will shortly achieve a temperature increase of at least 110 ° Celsius and thinks the technology could be in commercial use within 10 years.



More on: the advances behind the four scientific publications

The research group has published four scientific articles on their breakthroughs around the energy system during 2018.

1. Removing the need for toluene to be mixed with the molecule. Liquid Norbornadiene Photoswitches for Solar Energy Storage in the journal Advanced Energy Materials. https://onlinelibrary.wiley.com/doi/abs/10.1002/aenm.201703401

2. Increasing energy density and storage times. Molecular Solar Thermal Energy Storage in photoswitch oligomers increases energy densities and storage times in the journal Nature Communications. https://www.nature.com/articles/s41467-018-04230-8

3. Achieving energy storage of up to 18 years. Norbornadiene-based photoswitches with exceptional combination of solar spectrum match and long-term energy storage in Chemistry: A European Journal. https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.201802932

4. New record in how efficiently heating can be done. The liquid can increase 63C in temperature. Macroscopic Heat Release in a Molecular Solar Thermal Energy Storage System in the journal Energy and Environmental Science. https://pubs.rsc.org/en/content/articlehtml/2018/ee/c8ee01011k



