This problem has been burdening solar energy for a long time, but this can change, because it offers an ultra-intriguing way of saving solar energy.
Swedish scientists created a special fluid called "solar thermal energy". It is said that this fuel can store accumulated solar energy for more than a decade.
"Solar thermal fuels are like a rechargeable battery, but instead of electricity, you put the sun rays and get heat. It all depends on your needs," said Jeffrey Grossman, MIT engineer with these materials, NBC Nevs.
This liquid is in fact a special fluid molecule, for which scientists from the Čalmers University of Technology (Sweden) have been working for more than a year.
This molecule consists of carbon, hydrogen and nitrogen, and when exposed to the sunlight, it starts to behave unusually: the connections between the atoms are reset and the molecule becomes an isomer.
Like robbery in the trap, so solar energy is trapped in isomes with strong chemical bonds. And energy remains locked even when the molecule is cooled to room temperature.
When it comes to energy – for example, at night or in winter – the liquid is exposed to the catalyst, which returns the molecule to its original state and thereby relaxes energy.
"The energy in these isomers can be stored for up to 18 years," says one of the team's members, a scholar at the University of Chalmers, Kasper Moth-Poulsen. "When we decided to release the locked energy, we got an increase in heat that was higher than what we dare to expect."
Such a prototype of the energy system was placed on the roof of the university building, and when the new liquid was used and received highly optimistic results, the researchers attracted many investors.
Removable and non-polluting, the new energy device consists of a concave reflector with a centered tube that catches the sun's rays and acts as a kind of satellite antenna.
The MOST system works on a closed circuit. Allowed liquid through transparent tubes warmed the sun, and the so-called. Norbornadiene molecules in liquids are converted into isomeric quadricyclones that block heat. This liquid is then stored at room temperature to reduce energy loss.
When energy is needed, the liquid passes through a special catalyst, which returns the molecules back to its original shape, and this liquid increases to 63 degrees Celsius. It is therefore believed that this heat can be used in various heating systems in buildings.
The researchers repeatedly used the fluid 125 times – collecting sun heat, protecting and abandoning – and not noticing that this would damage these molecules.
"We recently made many important discoveries, and today we have an energy system that operates throughout the year and does not pollute the environment," said Moth-Poulsen.
According to NBC, scientists have made some discoveries that allowed their special liquid to store 250 watts per kilogram, which is twice the capacity of the Tesla Povervall battery system.
But there are still many opportunities for new achievements. Scientists believe that with the appropriate tools for manipulation they can get even more heat from such a system – at least 110 degrees Celsius.
"There is still a lot of work to do, and we have only managed to make this system functional. Now we have to ensure that everything is optimally engineered," says Moth-Poulsen.
If everything is planned, Moth-Poulsen believes that this technology can be started commercially for commercial purposes in the next 10 years.
Recent research results have been published in the journal Energi & Environmental Science.